DIY digital soldering station (ATmega8, C). DIY soldering station with hair dryer for atmega8

SOLDERING STATION DIAGRAM

I have long dreamed of soldering station, I wanted to go and buy it - but somehow I couldn’t afford it. And I decided to do it myself, with my own hands. I bought a hair dryer from Luckey-702 and began to slowly assemble it according to the diagram below. Why did you choose this particular electrical circuit? Because I saw photos of finished stations using it and decided that it was 100% working.

Schematic diagram of a homemade soldering station

The circuit is simple and works quite well, but there is a caveat - it is very sensitive to interference, so it is advisable to add more ceramics to the microcontroller power circuit. And if possible, make a board with a triac and an optocoupler on a separate printed circuit board. But I didn’t do that to save fiberglass. The circuit itself, firmware and seal are attached in the archive, only the firmware for the indicator with a common cathode. Fuses for MK Atmega8 in the photo below.

First, disassemble your hair dryer and determine what voltage your motor is set to, then connect all the wires to the board except the heater (the polarity of the thermocouple can be determined by connecting a tester). The approximate pinout of the wires of the Luckey 702 hair dryer is in the photo below, but I recommend disassembling your hair dryer and seeing what goes where, you know - the Chinese are like that!

Then apply power to the board and use variable resistor R5 to adjust the indicator readings to room temperature, then unsolder the resistor to R35 and adjust the motor supply voltage using trimmer R34. And if you have it at 24 volts, then adjust the 24 volts. And after that, measure the voltage on the 28th leg of the MK - there should be 0.9 volts, if this is not the case, recalculate the divider R37/R36 (for a 24 volt motor the resistance ratio is 25/1, I have 1 kOhm and 25 kOhm), the voltage is 28 leg 0.4 volts - minimum speed, 0.9 volts maximum speed. After this, you can connect the heater and, if necessary, adjust the temperature using the R5 trimmer.

A little about management. There are three buttons for control: T+, T-, M. The first two change the temperature; by pressing the button once, the value changes by 1 degree; if you hold it, the values ​​begin to change quickly. The M - memory button allows you to remember three temperature values, standardly these are 200, 250 and 300 degrees, but you can change them as you wish. To do this, press the M button and hold it until you hear the beeper signal twice in a row, then you can use the T+ and T- buttons to change the temperature.

The firmware has a cooling function for the hair dryer; when you place the hair dryer on the stand, it starts to be cooled by the motor, while the heater turns off and the motor does not turn off until it cools down to 50 degrees. When the hair dryer is on the stand, when it is cold or the engine speed is less than normal (at the 28th leg less than 0.4 volts) - there will be three dashes on the display.

The stand should have a magnet, preferably a stronger one or neodymium (from a hard drive). Since the hair dryer has a reed switch that switches the hair dryer to cooling mode when it is on the stand. I haven't made the stand yet.

The hair dryer can be stopped in two ways - by placing it on the stand or by turning the motor speed to zero. Below is a photo of my finished soldering station.

Video of soldering station operation

In general, the scheme, as expected, is quite sensible - you can safely repeat it. Best regards, AVG.

Forum on homemade stations

Discuss the article SOLDERING STATION DIAGRAM

radioskot.ru

Digital soldering station (DIY) DIY digital soldering station

Before assembling the soldering station, you need to understand all the elements of the circuit. List of elements for the circuit in the application. Once all the elements were assembled, I began designing the PCB. Several versions were developed on the forum pages over almost 300 pages. I preferred the version from the user Volly, version 3.0.

Unfortunately, there was no PCB version for parts in a DIP package, but only for SMD. I don’t like to solder such small parts, but after reading the forum, I realized that sometimes there are problems with such parts (contact - not contact, short circuit, overheating, etc.), and I didn’t have a soldering iron, I still use a regular 25W soldering iron from 220V network. Found printed circuit board from one user, but more than 50% redesigned for himself. On one board I placed an operational amplifier and the control circuit itself with a microcontroller.

The pinout of this display turned out to be as follows:

I installed the relay that I found on the market. The relay is rated for 12V and can withstand a maximum of 5A and 250V. To control the relay, the diagram indicated a transistor BC879, but I couldn’t find one, so I installed BC547. But in order to know which transistor can be installed, you need to know the relay parameters. Measure or look in the datasheet the resistance of the relay winding, in my case 190 Ohms, the relay winding is designed for a voltage of 12 V, respectively, according to Ohm’s law 12V/190 Ohms = 0.063 A. This means you just need to choose an n-p-n transistor with a permissible current of at least 63 mA. On the printed circuit board, the tracks for the relay must be calculated according to yours, which you have. Therefore, the power board (in the Relay part, you need to customize it to your liking)

Soldering iron connector. This is a 5-pin connector and is somewhat reminiscent of the connectors in old Soviet tape recorders. They work in some cases, but not in mine. After much searching, I decided that I would have to replace the connector. Replaced it with this:

I bought it on Aliexpress for about $1.

When choosing a soldering iron, please pay attention to its connector.

The transformer is toroidal with two secondary windings: the first is 24V, 3A, the second is 10V, 0.7A. also purchased. I didn't want to shake mine. It’s unlikely that it would have turned out cheaper, and there’s definitely more hassle. When all the parts were ready and sealed, the first thing I did was check the board for snot, short circuit, lack of soldering. Then I plugged it into the network (without a microcontroller) and checked the voltage sources: +5V and -5.6V. Then I checked the operational amplifier. At the amplifier output itself, the voltage should not exceed approximately 2.5V, maybe less. Instead of a soldering iron, I connected a variable resistor and checked how the voltage changes depending on the position of the resistor.

After all the maneuvers, I inserted the microcontroller into the panel and turned on the network. Everything worked right away, and the display looked like this:

This is what the station looks like in the final version.

I'm more than pleased with it. All the requirements that I thought about before development were fulfilled. It's been working for over a month now.

It should also be noted that the station is turned on by the yellow button on the front panel. But it turns off with a switch on the rear panel. Since the station has a function of complete auto-shutdown from the network, this arrangement suits me for now. But that's it for now. I think in the future, near the yellow button on the front panel, I will put the same one to turn it off, as provided in the circuit.

There is also a wire going to the soldering iron stand. It is needed to reset the countdown timer for sleep mode or disconnection from the network. If you set, for example, a timer for 5 minutes and you do not work with the soldering iron (you do not remove it from the stand or do not place it on it), the station will go into standby mode. As soon as you remove the soldering iron from the stand, the timer will immediately reset to 5 minutes (which you set) and begin counting down again. For me, this is very useful feature. The soldering iron will not heat up all night if you suddenly forget about it.

The archive contains all the files, photos, printed circuit boards, firmware, diagram, parts list, instructions. The station is quite easy to repeat. The main thing is to be careful and not to confuse anything.

tarasprindyn.blogspot.com

DIY hot air soldering station

I was once thinking about purchasing a soldering station for myself. A thing, of course, necessary in work. I looked a little on the Internet and realized that, to put it mildly, they are not very cheap. So I decided to make my own. I purchased a soldering iron with temperature control even earlier. Well, it was necessary to make a thermal air vent. Well, I decided not to bother with the design of the gun itself, and purchased a ready-made gun from some soldering station on Aliexpress. It cost me around $8 back then. Plus it has 4 attachments.

As soon as it arrived, I disassembled it and found inside a turbine, heating element, thermocouple, and reed switch (to turn off the flow of hot air when installed on the original stand, which has a magnet). Instead of a reed switch, I installed a button, since it is more convenient for me.

Next it was necessary to make a control unit. It required an ATMega8 type MK, a 7-segment 4-character display, 3 buttons, an op-amp (Any with a 5V power supply), a BT136 triac, with a MOC3021 driver, and wiring components (resistors, capacitors). The diagram and firmware with sources are below. The firmware is not very well developed yet, but it works, I'll redo it someday.

After assembly and firmware, the soldering iron needs to be calibrated. We install the thermocouple from the multimeter as close as possible to the hot air outlet nozzle, turn on the soldering iron, hold down all three buttons until the word CALL appears. Then calibration begins at eight points (50,100,150,200,250,300,350,400 degrees). The +- buttons turn on/off the heating element. As soon as the multimeter readings correspond to the calibrated temperature, press the Enter button and also calibrate the next point. After calibration, all values ​​are saved to the Eeprom memory of the controller. Using a hairdryer is easy: turn it on, press Enter, set the desired temperature, Enter again and wait for the soldering iron to reach temperature. When this happens, Ok will appear on the display. The button on the handle can be used to turn the soldering iron on and off.

SOURCE FOR CVAVR AND SCHEME. DOWNLOAD.

elschemo.ru

DIY soldering stations - a practical guide with diagrams and a list of necessary parts

Any radio amateur who respects himself and his work strives to have at hand all necessary tool. Naturally, you can’t do without a soldering iron. Today, radioelements and parts that most often require attention, repair, replacement and, therefore, the use of soldering are no longer the massive boards that they used to be. The tracks and conclusions are becoming thinner, the elements themselves are becoming more sensitive. You need not just a soldering iron, but a whole soldering station. The ability to monitor and regulate temperature and other process parameters is necessary. Otherwise, there is a risk of serious property damage.

A high-quality soldering iron is not the cheapest pleasure, let alone a station. Therefore, many hobbyists are interested in how to make soldering stations with their own hands. For some, it’s even a matter of not only saving money, but also their pride, level and skill. What kind of radio amateur is he who cannot implement the most necessary thing - a soldering station?

Today, a lot of options for circuits and parts that are necessary to make a soldering station with your own hands are widely available. The soldering station ultimately turns out to be digital, since the circuits provide for the presence of a digital programmable microcontroller.

Below is a diagram that is popular among radio amateurs. This scheme is noted as one of the easiest to implement and at the same time reliable.

DIY soldering station diagram. Element base

The main working tool of a soldering station is obviously a soldering iron. If you don’t even have to buy new parts for other parts, but use suitable ones from your arsenal, then you need a good soldering iron. Comparing prices and characteristics, many highlight soldering irons Solomon, ZD (929/937), Luckey. Here you should choose based on your needs and wishes.

Typically, such soldering irons are equipped with a ceramic heater and a built-in thermocouple, which greatly simplifies the process of implementing a thermostat. Soldering irons from these manufacturers are also equipped with a connector suitable for connecting to the station. Thus, there is no need to remake the connector.

When a soldering iron is selected for a soldering station, based on its power and supply voltage, the following are selected: a suitable diode bridge for the circuit and a transformer. To obtain +5V voltage, you need a linear stabilizer with a good heatsink. Or, as an option, a transformer with a voltage of 8-9V with a separate winding to power the digital part of the circuit. The optimal microcontroller option for assembling a soldering station is ATmega8. It has built-in programmable memory, ADC and calibrated RC oscillator.

At the PWM output as field effect transistor IRLU024N has proven itself well. Or you can take any other suitable analogue. The specified transistor does not require a radiator.

At home, as a necessary element of a soldering station, it is quite possible to make a soldering iron with your own hands, which is the main element of a soldering station.

You can get tips on how to properly solder copper and other wires, microcircuits, and radio elements here.

The diagram shows 2 LEDs to indicate operating modes. You can replace them with one two-color one. Also, based only on your own preferences, you can install or not install sound indicators that sound when pressing buttons. This will not affect the functionality of the soldering station and its performance of its main tasks.

In assembling such circuits, stale but serviceable Soviet-made radioelements can be successfully used.

Some of them may require some modernization in order to synchronize and adapt them with other components. But the only criterion by which you should choose is whether the ratings comply with the necessary requirements of the circuit. Thus, transformers of the TS-40-3 type, which were previously installed in turntables for vinyl records, can be used.

Purpose of the buttons. Firmware options

The soldering station buttons will have the following functions:

• U6.1 and U7 are responsible for changing the temperature: accordingly, U6.1 reduces the set value by 10 degrees, and U7 increases it;
• U4.1 is responsible for programming temperature modes P1, P2, P3;
• buttons U5, U8 and U3.1 are responsible for individual modes, respectively: P1, P2 and P3.

Also, instead of buttons, an external programmer can be connected to flash the controller firmware. Or in-circuit firmware is being performed. Setting the temperature settings is easy. You can not flash the EEPROM, but simply connect the station with the U5 key pressed, as a result of which the values ​​of all modes will be equal to zero. Next, the settings are carried out using the buttons. When flashing the firmware, you can configure different meanings temperature adjustments. The step can be 10 degrees or 1 degree, depending on your needs.

Temperature regulator for low-voltage soldering irons

For those who are just starting their experiments in electrical engineering, assembling a somewhat simplified circuit can serve as a kind of training.

Essentially, this is also a homemade do-it-yourself soldering station, but with a few disabilities, since a different microcontroller will be used here. Such a station will be able to service both standard low-voltage soldering irons with a voltage of 12V, and hand-made copies, such as micro-soldering irons assembled on the basis of a resistor. The circuit of a homemade soldering station is based on the regulator system of a network soldering iron.

The operating principle is to adjust the input power values ​​by skipping periods. The system operates on a hexadecimal number system and, accordingly, has 16 levels of regulation.

Everything is controlled by one “+/-” button. Depending on how many times you press and what sign, the skipping of periods on the soldering iron decreases or increases, and the readings increase or decrease accordingly. The same button is used to turn off the device. It is necessary to hold down “+” and “-” at the same time, then the indicator will blink, the regulator will turn off and the soldering iron will cool down. The device turns on in the same way. At the same time, he “remembers” the stage at which the shutdown occurred. Any home craftsman or novice electrician is interested in the question: which connection diagram for a three-phase meter is most suitable in his apartment or house? In addition to this topic, here you can study in detail the principle of operation of an RCD, and this article will teach you how to accurately check a capacitor with a multimeter. You can flash the controller microcontroller using the PICPgm ProgrammerIC-Prog program, setting the fuses in the latter: WDT, PWRT, BODEN.

Video on how to make a soldering station with your own hands:

elektrik24.net

DIY soldering station. It couldn't be simpler

Regarding soldering the voltmeter. It has 3 outputs: the first and second are power supply, and the third is measuring.

You can also paint over the point on the voltmeter so that it doesn’t confuse us. To do this, we will use a black marker.

After this you can turn it on. The author takes food from laboratory block.

If the voltmeter shows 0 and the circuit does not work, you may have connected the thermocouple incorrectly. The circuit, assembled without jambs, starts working immediately. Checking the heating.
Everything is fine, now you can calibrate the temperature sensor. To calibrate the temperature sensor, you must turn off the heater and wait until the soldering iron cools down to room temperature.
Next, by rotating the potentiometer with a screwdriver, we set the pre-known room temperature. Then turn on the heater for a while and let it cool. For accuracy, it is better to calibrate a couple of times.

Now let's talk about the power supply. The finished board looks like this:

It is also necessary to wind a pulse transformer to it.
You can see how to wind it in one of the author’s previous videos. Below you can see a screenshot of the winding calculations, it may be useful to someone.
At the output of the block we get 22-24 volts. We took the same thing from the laboratory block.
Housing for the soldering station. When the scarves are ready, you can start creating the housing. At the base there will be such a neat box.

First of all, it is necessary to draw a front panel for it to give it a marketable appearance, so to speak. This can be done easily and simply in FrontDesigner.

Next, you need to print the stencil and use double-sided tape to secure it to the end and go make holes for spare parts. The case is ready, now all that remains is to place all the components inside the case. The author put them on hot glue, since these electronic components have virtually no heating of any kind, so they will not go anywhere, and will stick perfectly to the hot glue. At this point, production is completed. You can start testing. As you can see, the soldering iron does an excellent job of tinning large wires and soldering large arrays. In general, the station performs well.

Why not just buy the station? Well, first of all, it’s cheaper to assemble it yourself. For the author, the production of this soldering station cost 300 hryvnia. Secondly, in the event of a breakdown, you can easily repair such a homemade soldering station.

Thank you for attention. See you again!

usamodelkina.ru

DIY digital soldering station

Composition: ATmega8, LM358, IRFZ44, 7805, bridge, 13 resistors, one potentiometer, 2 electrolytes, 4 capacitors, three-digit seven-segment LED indicator, five buttons. Everything is placed on two boards measuring 60x70mm and 60x50mm, located at an angle of 90 degrees.

I purchased the soldering iron from soldering stations ZD-929, ZD-937.

The soldering iron has a ceramic heater and a built-in thermocouple. Soldering iron connector pinout for ZD-929:

Functionality: Temperature from 50 to 500 degrees, (heating to 260 degrees in about 30 seconds), two buttons +10 degrees and -10 degrees temperature, three memory buttons - long press (until blinking) - memorizing the set temperature (EE), short - setting the temperature from memory . After power is applied, the circuit sleeps; after pressing the button, the installation from the first memory cell is turned on. When you first turn on the temperature in memory is 250, 300, 350 degrees. The set temperature blinks on the indicator, then the tip temperature runs and then lights up with an accuracy of 1 g in real time (after heating, it sometimes runs 1-2 g ahead, then stabilizes and occasionally jumps by +-1 g). 1 hour after the last manipulation of the buttons, it falls asleep and cools down (protection against forgetting to turn it off). If the temperature is more than 400 degrees, he falls asleep after 10 minutes (to preserve the sting). The beeper beeps when turned on, buttons are pressed, recorded in memory, the set temperature is reached, it warns three times before falling asleep (double beep), and when falling asleep (five beeps).

Element ratings: R1 - 1M R2 - 1k R3 - 10k R4 - 82k R5 - 47k R7, R8 - 10k R indicator -0.5k C3 - 1000mF/50v C2 - 200mF/10v C - 0.1mF Q1 - IRFZ44 IC4 - 7805

1. The transformer and diode bridge are selected based on the supply voltage and power of the soldering iron used. For me it is 24 V / 48 W. To obtain +5 V, a linear stabilizer 7805 is used. Or a transformer with a separate winding is needed to power the digital part with a voltage of 8-9 V. I got a power supply from some old branded computer - DELTAPOVER, pulse generator, 18 volts, 3 amperes, size like two packs of cigarettes, works great, even without a cooler. 2. Field-effect transistor at the PWM output - any suitable one (I have IRFZ44). 3. The first LED I came across in a radio store, I was disappointed when I called at home and found out that the sign segments inside were not parallel, so the board became more complicated. It is marked on the side “BT-C512RD” and lights up green. You can use any indicator or three with appropriate adjustments to the board, and if the anode is common, then the firmware (firmware option below). 4. A beeper with a built-in generator, connects + to the 14th leg of the mega, - to the minus power supply (not on the diagram or board, because I came up with it later).

5. Purpose of the buttons: S1: On / -10°C S2: +10°C S3: Memory 1 S4: Memory 2 S5: Memory 3

Firmware for the controller can be done using an external programmer; the controller is installed on a socket; I didn’t bother with the J-tag. When flashing the firmware, the internal 8 MHz RC oscillator of the crystal is turned on, in AVR the value of the “set” bit corresponds to logical zero, in Pony-Prog it looks like this:

Now about the firmware. Of all those that took place during development, 2 final options are relevant: 1. For LEDs with a common cathode. 2. For LEDs with a common anode.

This is my finished design:

Another version

Download printed circuit boards (47 Kb). Downloads: 3214 Download firmware (updated versions) (10 Kb). Downloads: 2838

eldigi.ru

Simple Solder MK936. A simple DIY soldering station

There are a lot of diagrams of various soldering stations on the Internet, but they all have their own characteristics. Some are difficult for beginners, others work with rare soldering irons, others are not finished, etc. We have focused specifically on simplicity, low cost and functionality, so that every novice radio amateur can assemble such a soldering station. Please note that we also have a version of this device with SMD components!

What is a soldering station for?

An ordinary soldering iron, which is connected directly to the network, simply heats constantly with the same power. Because of this, it takes a very long time to warm up and there is no way to regulate the temperature in it. You can dim this power, but achieving a stable temperature and repeatable soldering will be very difficult. A soldering iron prepared for a soldering station has a built-in temperature sensor and this allows you to apply maximum power to it when warming up, and then maintain the temperature according to the sensor. If you simply try to regulate the power in proportion to the temperature difference, then it will either warm up very slowly, or the temperature will fluctuate cyclically. As a result, the control program must necessarily contain a PID control algorithm. In our soldering station, we, of course, used a special soldering iron and paid maximum attention to temperature stability.

Soldering station Simple Solder MK936

Specifications

1. Powered by 12-24V DC voltage source
2. Power consumption, when powered 24V: 50W
3. Soldering iron resistance: 12ohm
4. Time to reach operating mode: 1-2 minutes depending on supply voltage
5. Maximum temperature deviation in stabilization mode, no more than 5 degrees
6. Control algorithm: PID
7. Temperature display on a seven-segment indicator
8. Heater type: nichrome
9. Temperature sensor type: thermocouple
10. Temperature calibration capability
11. Setting the temperature using the ecoder
12. LED to display soldering iron status (heating/operating)

Schematic diagram

The scheme is extremely simple. At the heart of everything is the Atmega8 microcontroller. The signal from the optocoupler is fed to an operational amplifier with adjustable gain (for calibration) and then to the ADC input of the microcontroller. To display the temperature, a seven-segment indicator with a common cathode is used, the discharges of which are switched on through transistors. When rotating the BQ1 encoder knob, the temperature is set, and the rest of the time the current temperature is displayed. When turned on, the initial value is set to 280 degrees. Determining the difference between the current and required temperature, recalculating the coefficients of the PID components, the microcontroller heats up the soldering iron using PWM modulation. A simple 5V linear stabilizer DA1 is used to power the logical part of the circuit.

Schematic diagram Simple Solder MK936

Printed circuit board

The printed circuit board is single-sided with four jumpers. The PCB file can be downloaded at the end of the article.

Printed circuit board. Front side

Printed circuit board. back side

List of components

To assemble the printed circuit board and housing, you will need the following components and materials:

1. BQ1. Encoder EC12E24204A8
2. C1. Electrolytic capacitor 35V, 10uF
3. C2, C4-C9. Ceramic capacitors X7R, 0.1uF, 10%, 50V
4. C3. Electrolytic capacitor 10V, 47uF
5. DD1. Microcontroller ATmega8A-PU in DIP-28 package
6. DA1. L7805CV 5V stabilizer in TO-220 package
7. DA2. Operational amplifier LM358DT in DIP-8 package
8. HG1. Seven-segment three-digit indicator with a common cathode BC56-12GWA. The board also has a seat for a cheap analogue.
9. HL1. Any indicator LED for a current of 20 mA with a pin pitch of 2.54 mm
10. R2,R7. Resistors 300 Ohm, 0.125W - 2 pcs.
11. R6, R8-R20. Resistors 1kOhm, 0.125W - 13pcs
12. R3. Resistor 10kOhm, 0.125W
13. R5. Resistor 100kOhm, 0.125W
14. R1. Resistor 1MOhm, 0.125W
15. R4. Trimmer resistor 3296W 100kOhm
16. VT1. Field effect transistor IRF3205PBF in TO-220 package
17. VT2-VT4. Transistors BC547BTA in TO-92 package - 3 pcs.
18. XS1. Terminal for two contacts with pin spacing 5.08 mm
19. Terminal for two contacts with pin spacing 3.81 mm
20. Terminal for three contacts with pin spacing 3.81 mm
21. Radiator for stabilizer FK301
22. Housing socket DIP-28
23. Housing socket DIP-8
24. Soldering iron connector
25. Power switch SWR-45 B-W(13-KN1-1)
26. Soldering iron. We will write about it later
27. Plexiglas parts for the body (cutting files at the end of the article)
28. Encoder knob. You can buy it, or you can print it on a 3D printer. File for downloading the model at the end of the article
29. Screw M3x10 - 2 pcs.
30. Screw M3x14 - 4 pcs.
31. Screw M3x30 - 4 pcs
32. Nut M3 - 2 pcs.
33. M3 square nut - 8 pcs
34. Washer M3 - 8 pcs
35. M3 locking washer - 8 pcs
36. Assembly will also require installation wires, zip ties and heat shrink tubing.

This is what a set of all the parts looks like:

Set of parts for assembly of the Simple Solder MK936 soldering station

PCB installation

When assembling a printed circuit board, it is convenient to use the assembly drawing:

Assembly drawing PCB soldering station Simple Solder MK936

The installation process will be shown and commented on in detail in the video below. Let us note only a few points. It is necessary to observe the polarity of electrolytic capacitors, LEDs and the direction of installation of microcircuits. Do not install microcircuits until the case is completely assembled and the supply voltage has been checked. ICs and transistors must be handled carefully to avoid damaging them from static electricity. Once the board is assembled, it should look like this:

Soldering station printed circuit board assembly

Housing assembly and volumetric installation

The block wiring diagram looks like this:

Soldering station wiring diagram

That is, all that remains is to supply power to the board and connect the soldering iron connector. You need to solder five wires to the soldering iron connector. The first and fifth are red, the rest are black. You should immediately put a heat-shrink tube on the contacts, and tin the free ends of the wires. The short (from the switch to the board) and long (from the switch to the power source) red wires should be soldered to the power switch. Then the switch and connector can be installed on the front panel. Please note that the switch may be very difficult to engage. If necessary, modify the front panel with a file!

The next step is to put all these parts together. There is no need to install the controller, operational amplifier or screw on the front panel!

Assembling the soldering station housing

Controller firmware and setup

You can find the HEX file for the controller firmware at the end of the article. The fuse bits must remain factory-set, that is, the controller will operate at a frequency of 1 MHz from the internal oscillator. The first power-up should be done before installing the microcontroller and operational amplifier for a fee. Serve constant pressure supply from 12 to 24V (red should be “+”, black “-”) to the circuit and check that between pins 2 and 3 of the DA1 stabilizer there is a supply voltage of 5V (middle and right pins). After this, turn off the power and install the DA1 and DD1 chips into the sockets. At the same time, monitor the position of the chip key. Turn on the soldering station again and make sure that all functions work correctly. The indicator displays the temperature, the encoder changes it, the soldering iron heats up, and the LED signals the operating mode. Next, you need to calibrate the soldering station. The best option for calibration is to use an additional thermocouple. It is necessary to set the required temperature and control it on the tip using a reference device. If the readings differ, then adjust using the multi-turn trimming resistor R4. When adjusting, remember that the indicator readings may differ slightly from the actual temperature. That is, if you set, for example, the temperature to “280”, and the indicator readings deviate slightly, then according to the reference device you need to achieve exactly a temperature of 280°C. If you don’t have a control one at hand measuring instrument, then you can set the resistor resistance to about 90 kOhm and then select the temperature experimentally. After the soldering station has been checked, you can carefully install the front panel so that the parts do not crack.

Soldering station assembly

Soldering station assembly

Video of work

We made a short video review …. And detailed video, which shows the build process:

Conclusion

This simple soldering station will greatly change your soldering experience if you have soldered before with a regular corded soldering iron. This is what it looks like when the assembly is complete. A few more words need to be said about the soldering iron. This is the simplest soldering iron with a temperature sensor. It has a regular nichrome heater and the cheapest tip. We recommend that you immediately purchase a replacement tip for it. Any with an outer diameter of 6.5mm, an inner diameter of 4mm, and a shank length of 25mm will do.

Soldering iron disassembled with spare tip

Downloads

Printed circuit board in Sprint Layout formatFirmware for microcontrollerFile for cutting plexiglassModel of encoder handle for 3D printing

UPD

The files posted above are outdated. In the current version, we have updated the drawings for cutting plexiglass, making a printed circuit board, and also updated the firmware to remove the flickering indicator. Please note that for new version firmware, you need to enable CKSEL0, CKSEL2, CKSEL3, SUT0, BOOTSZ0, BOOTSZ1 and SPIEN (that is, change the standard settings). Printed circuit board in Sprint Layout V1.1 format Firmware for microcontroller V1.1 File for cutting plexiglass V1.1

This soldering station can also be purchased as a kit for self-assembly in our store and from our partners GOOD-KITS.ru and ROBOTCLASS.ru.

IN Soviet times The radio components of the microcircuits were quite large in size. Therefore, equipment repair technicians used a regular soldering iron for installation. Today, with the advent of SMD elements, printed circuit boards have become compact, which has reduced the size of equipment. However, this coin also has a downside - overheating of SMD elements leads to their failure, and special equipment has a high cost. A good solution would be a do-it-yourself soldering station, the production of which will not require large expenses. Today we’ll talk about such a device, let’s figure out how difficult it is to make it yourself and what it will take.

Read in the article:

Why do you need a soldering station: areas of application

A regular soldering iron can heat up to 400°C. This temperature is quite suitable for soldering wires or repairing microcircuits from the USSR era. But if you need to work with new SMD printed circuit boards, you need a completely different temperature regime– 260−280°С. Otherwise, when replacing one radio component, the technician will damage several elements around it. This is where a soldering station comes to the rescue, allowing you to set the optimal temperature.

Helpful information! Working with a soldering station (SS) requires some skills. Therefore, before choosing a soldering station and using it to repair expensive and complex equipment, it is worth practicing on unnecessary printed circuit boards. Otherwise, there is a risk of permanently damaging the equipment.

Operating principle of the PS, general characteristics of the equipment

If we exaggerate, the principle of operation of the PS can be compared with a conventional soldering iron connected through a rheostat. However, a modern soldering station is a more complex electronic device that has many additional functions. In addition, the PS can also be contactless (airborne).

The main functions of modern soldering stations are:

• possibility of adjusting the heating of the tip. The more accurately and smoothly the adjustment is made, the easier it is for the master to work;
• mandatory presence of overheating protection;
• The temperature of the tip is controlled automatically; as it cools, the power increases.

Each model has its own additional functions. If you make it yourself, you can stick to the simplest option. Especially if there is no experience in creating such devices. But the listed parameters are required. If even one of the points in the characteristics is missing, it will be impossible to call the assembled equipment a station.

Division of PS into types according to design features

The soldering station can be air (thermal air), contact, combined or infrared. Each of these types has its own area of ​​application. First, let's look at general information for each type, and then we’ll figure out how to independently make the most popular of them – thermal air and infrared.

Contact soldering station: device features

The contact PS is a regular soldering iron equipped with a thermostat. The temperature controller can be mechanical or electronic. The price of such a soldering station is significantly lower than the cost of other types. Such equipment can be purchased for 900−1000 rubles. The cost of contact PS with the function of stabilizing heating when touching surfaces is slightly higher. When the tip touches an unheated printed circuit board, the automation increases power.

Contactless infrared PS: what is it?

The most modern of all types. Thanks to infrared radiation, the device heats the surface of the printed circuit board. At the same time, the heating of radio components located on its surface is minimal. The cost of such equipment is higher than that of other types. For example, the infrared PS “TornadoInfra Pro” can be purchased at a price of 22,000 rubles.

Hot air soldering equipment

The design of the device includes a compressor. The air supplied by it passes through the soldering iron, heating up from the tip. It is this heated air flow that heats up the printed circuit board and solder.

Interesting to know! There are specialized dismantling hot air soldering stations. Their compressor works in the opposite direction - suction, which allows you to immediately remove solder particles from the surface.

The cost of a dismantling station is significantly higher. If a regular hot-air PS “Lukey 852D+ with soldering iron” can be purchased for 5,300 rubles, then a dismantling “AOYUE 701A++” will cost 13,000 rubles.

Combined substations and their features

These stations have two types - contact and thermal air. Using a hot air gun, the printed circuit board is heated, after which the elements are soldered off quite easily with a tip.

Expert opinion

Tool selection consultant at VseInstrumenty.ru LLC

“The most common operating temperature range is from +120 to +420°C. This is enough to work with all types of radio equipment that exist today.”

Examples of soldering stations of various types:

Hot air soldering station: do-it-yourself nuances

The work of making a homemade soldering station with a hairdryer with your own hands is carried out in several stages. First, a hot air gun is designed, then a control unit, and then the station is assembled and configured. At the same time, the hot air gun itself can be purchased in a store or online. Its cost is low, and such an acquisition will greatly simplify the work of producing PS. However, it is best to make your own soldering hair dryer, which does not require electronic unit management. It is quite convenient to use, and the cost of parts for its assembly tends to zero. We will need:

• glass tube from an electric fireplace;
• nichrome spiral from the same place;
• silicone hose;
• thin glass tube;
• an old, non-working soldering iron.

Let's figure out step by step using examples how this work is done.

DIY soldering station: step-by-step instructions

Illustration	Action to be performed
	Inside the glass tube from the electric fireplace we insert a nichrome spiral from the same. One side will have to be stretched so that the contacts extend to one edge of the tube.
	We secure the nichrome thread stretched from the outside along the glass tube with simple electrical tape. Now we need to put the body of the soldering iron on the side of the ends of the spiral so that there are contacts on the edge to which we will connect the power. It is better to protect the contacts themselves with insulators from the same old soldering iron, remaining after disassembling it.
	We connect the silicone and thin glass tube. We place the glass one inside the body of the soldering iron. It is through these tubes that air will flow.
	We wrap the assembled structure with a layer of varnished fabric. This is done so that you can freely hold the Nashtermofen in your hands. Similar material is sold in any hardware store.
	That's almost all, the air soldering station is ready. All that remains is to supply air (yellow arrow) and 220V power (red arrow). Air can be supplied using a regular aquarium compressor.

As you can see, the manufacturing process of such a hot air gun is quite simple at minimal cost. If we talk about factory-made equipment, you can buy a soldering station with a hair dryer for about 5,000 rubles. Agree, good savings. If you still decide to purchase such a device, before doing so, you should figure out how to solder with a hairdryer from a soldering station. Our video instructions will help with this.

How to use a soldering station with a hot air gun: video instructions

We hope that after watching the video tutorial, our readers have no questions about using the hot-air PS. To summarize this section, we suggest that you familiarize yourself with several diagrams of soldering guns that you can assemble yourself.

Simple do-it-yourself soldering gun circuits

Here the editors of the site present to your attention diagrams of the simplest hot air guns, as well as an example of how to make a housing for it.

Do-it-yourself budget infrared soldering station - is it possible?

Not everyone can easily pay 20,000 rubles. and more for similar equipment. And if, moreover, soldering is required infrequently, then there is no point in purchasing a factory-made PS. Let's try to consider the option in which you have in your hands a budget infrared soldering iron made by yourself.

Illustration	Description of action
	We will need a regular car cigarette lighter. We disassemble it, leaving only the spiral on the hairpin. It will become the basis of our IR soldering iron.
	We disassemble a soldering iron bought in a store for 100 rubles. Such a product cannot be used for its intended purpose, but for our purpose it is ideal. We leave the insulators and, having attached the cigarette lighter spiral, install the resulting structure inside the soldering iron body.
	You need to weld the cigarette lighter spiral to the body of the soldering iron. If it is not possible to use such a device, you can use “cold welding”.
	This is how our infrared soldering station works. Many may say that a voltage regulator is needed, however, this is a misconception. The editors of the site came to the conclusion that it is easier and more convenient to adjust the heating intensity by moving the spiral closer or further away. But…
	...if you think that adjustment is necessary, you can include a dimmer like this in the circuit. It is also possible to install a power button on the handle of the soldering iron, but in this case you will have to include a relay in the circuit. Otherwise, the button will instantly burn out.

A homemade IR soldering station with your own hands is very simple, as you can see.

DIY soldering station on Arduino: manufacturing features

To make such a PS we will need a soldering iron for a soldering station. Such a pen can be purchased online, just like an Arduino chip. We will not go into details because for a person far from radio engineering and digital technologies, the production of such a PS is almost impossible, and it makes no sense to explain programming and assembly technology to those who are knowledgeable in this topic. Let’s just say that on the basis of such a microcontroller you can assemble a full-fledged soldering station, which is not inferior in characteristics to a factory-made device.

Features of do-it-yourself soldering stations on Atmega8

A do-it-yourself soldering station based on the Atmega 8 microcontroller is in no way inferior to the previous version, however, there is one difference that may be decisive for some. The Arduino microcontroller costs about $3, while the Atmega 8 costs only $1. Otherwise, such PSs will be almost identical. We invite you to familiarize yourself with the diagrams of similar equipment based on Atmega 8 and Arduino microcontrollers.

Summarize

Of course, if such equipment is used at a professional level (and constantly), then it is better to purchase a factory-assembled PS. But for one-time electronics repairs, making a soldering station yourself can be an ideal solution. We hope that the information presented in today's article was useful to our readers. If you still have any questions, do not hesitate to ask them in the discussions below. Perhaps you have experience in assembling soldering stations yourself? Then we kindly ask you to share your thoughts on this topic with less experienced home craftsmen. This will help them learn something new. Write, ask, communicate. And finally, we suggest watching another short video on today’s topic.

The article discusses a homemade microcontroller control unit for a soldering station, which includes a low-voltage soldering iron and an industrial soldering iron. The block can also be used as a two-channel general purpose temperature meter with thermocouples as its sensors and as a single-channel temperature controller.

In amateur radio practice, very often there is a need for a convenient miniature soldering iron for working with small radio components, which has a low supply voltage, adjustable tip temperature and the ability to ground it. The latter significantly reduces the risk of damage to electronic components from static electricity discharges.

Many descriptions of the designs of soldering irons and soldering guns (hereinafter referred to as simply hair dryers) have been published in the literature, but self-production Most of them require special equipment, suitable materials and a significant investment of time. However, today it is possible to purchase a ready-made, easy-to-use soldering iron and hair dryer with replaceable attachments for a low price.

There are two common design options for soldering irons, differing in the methods of heating the tip and measuring its temperature. In the first version, the heater covers the soldering rod (as in classic electric soldering irons). The temperature is measured using a thermocouple pressed against its shank, opposite the tip. In this design, the heating coil is reliably protected from mechanical stress and damage. But the readings of a temperature sensor located a considerable distance from the actual soldering site have a noticeable inertia. It takes some time for the heat removal from the tip (tip) to lead to a decrease in the temperature of the shank. In practice, this disadvantage is compensated by a certain margin in the temperature of the rod and its high heat capacity, which ensures rapid heating of the soldering area. The control system detects a decrease in temperature only during prolonged continuous soldering and returns it to the set value, increasing the power supplied to the heater.

The second option differs in that the heater is located inside the rod, the temperature sensor is pressed against the heater point closest to the soldering point. This ensures a faster response to changes in tip temperature during the soldering process. Such soldering irons usually use a fragile ceramic heater, which is easily damaged when the soldering iron falls on a hard surface or in the case of other strong mechanical loads, or internal mechanical stresses resulting from uneven heat transfer (for example, when working with a non-standard tip).

Another working tool of a modern soldering station is a hair dryer. With its help, the required areas of the printed circuit board are heated without contact to the melting temperature of the solder using an air flow of a given strength and temperature. The hair dryer is also convenient for group soldering of passive electronic components. They are first laid out on the printed circuit board, covering the soldering areas with a layer of solder paste. During the soldering process, these components self-center on the board pads due to the surface tension forces of the molten solder.

The hair dryer has gained great popularity among repairmen, since it can be used to quickly desolder and solder multi-lead microcircuits with fine pin pitches. A hair dryer is also very convenient for warming up heat-shrinkable tubes and for blowing hard-to-reach areas of structures with warm or cold air.

Previously, soldering guns operated from a compressor, which was located in a separate housing and supplied air through a hose to the handle of the hair dryer, in which a heater and temperature sensor were installed. The need for a remote compressor and its high price restrained the spread of such hair dryers in the workplace of radio amateurs. With the advent of hair dryers with built-in fans, it became possible to abandon bulky compressors.

In Fig. 1 shows a photograph of a disassembled soldering iron from the Solomon SL-10/30 soldering station with a temperature sensor installed according to the first of the options described above, and a hair dryer from the soldering station Lukey station 852D+ FAN with built-in fan. It is for working with them that the proposed control unit was developed.

A nichrome heater and temperature sensor are installed in the metal casing of the front of the hair dryer. The design of the heater is similar to those used in hair dryers. The heater supply voltage is 220 V, power is about 250 W. In the extended part of the hair dryer handle there is a centrifugal fan with a supply voltage of 24 V (current consumption 120 mA). I would like to draw your attention to the fact that the outer diameter of the metal part of the nozzle of this hair dryer is 25 mm, in contrast to popular “compressor” hair dryers with an outer nozzle diameter of 22 mm. As a result, it requires special attachments, and an adapter is required to install others. A homemade nozzle with a round outlet of small diameter, shown in Fig. 2, the author made it from an old oxide capacitor K50-3 20 uF at 350 V and a car clamp.

Considering that a soldering iron and a hair dryer are usually not used at the same time, it was decided to simplify the unit being developed by combining the controls for these tools and using the same indicators to display their temperature and operating mode.

Main technical characteristics

Supply voltage and frequency, V (Hz) ...............220 (50)

Soldering iron heater supply voltage, V................24

Soldering iron heater power, W...................48

Maximum temperature

Soldering iron, oC...................420

Hair dryer heater supply voltage, V...................220

Hairdryer heater power, W...................250

Maximum temperature

Air flow, оС............480

Display resolution

Temperatures, oC................1

The diagram of the soldering station control unit with a soldering iron and hair dryer connected to it is shown in Fig. 3. The button in the hair dryer, marked SB2 in the diagram, is not used. The control unit is built on the basis of a PIC16F887 (DD1) microcontroller, which includes a ten-bit ADC and is configured to operate from a built-in clock generator with a frequency of 8 MHz. Connector X4 is provided for programming the microcontroller. Ceramic capacitors C14 and C15 are installed as close as possible to the microcontroller power pins. To supply sound signals, a sound emitter with a built-in generator HA1 is used, which is controlled by signals from pin 40 (RB7) of the microcontroller through an electronic switch on transistor VT3.

The temperature is measured using thermocouples BK1 and BK2 installed inside the hair dryer and soldering iron, respectively. Op amps DA1.1 and DA1.2 enhance their thermoEMF. The cold junctions of thermocouples are physically located in the handles of the soldering iron and hair dryer; compensation for changes in their temperature is not provided. In practice, the absence of such compensation does not cause noticeable inconvenience, since soldering is usually carried out in rooms with little changing temperature.

The microcontroller's supply voltage (5 V) was used as a reference voltage for the microcontroller's ADC. This did not lead to a noticeable error. The ADC external reference voltage input pin is left free and, if desired, can be used to connect an external reference voltage source of increased stability, for example, the MCP1541 (4.096 V) or MCP1525 (2.5 V) microcircuit. When changing the reference voltage, a corresponding adjustment of the gains of the op-amps DA1.1 and DA1.2 will be required. These coefficients are set using resistors R4, R8 for DA1.1 and R6, R9 for DA1.2. They should be selected so that at maximum temperature the voltage at the output of the op-amp does not exceed the value of the reference ADC voltage.

In the event of breaks in the thermocouple circuits (including when disconnected from connectors X2 and X3 in the plug or hair dryer), a voltage of +12 V is supplied through resistors R2 and R3 to the non-inverting inputs of the op-amp. Circuits R5C1 and R7C2 are filters that suppress high-frequency interference. Resistors R10 and R11, together with protective diodes located inside the microcontroller, protect the ADC inputs from overload.

The power control of the soldering iron heater is organized using a PWM microcontroller hardware module. It generates variable duty cycle pulses at pin 17 (RC2). Using a powerful switch on the field-effect transistor VT1, they turn the heater on and off, changing the average power consumed by it. The average voltage supplied to the hair dryer fan is changed using PWM implemented in software. Pulses from pin 16 (RC1) of the microcontroller are supplied to the fan motor M1 through a switch on the field-effect transistor VT2.

Adjusting the power of the hair dryer heater is carried out by periodically skipping a certain number of periods mains voltage. The control signal is generated by the microcontroller at pin 10 (RE2) and enters the heater power circuit through the dinistor optocoupler U1, equipped with a switch-on synchronization unit with the moment of zero crossing of the voltage applied to its output circuit, and triac VS1. The HL1 LED is designed for visual monitoring of the operation of the hair dryer heater.

The block uses a four-digit, seven-element LED indicator HG1 - RL-F5610GDAW/D15 with common cathodes of the elements of each digit. The anodes of the elements are connected to port D of the microcontroller DD1 through current-limiting resistors R24-R31, which are selected so that the total current through all pins of port D when any sign is displayed does not exceed 90 mA. The common cathodes of the indicator bits switch the switches on transistors VT5-VT8 according to the signals generated at the RC4-RC7 pins of the microcontroller.

LEDs HL4-HL11 included in common system dynamic indication as elements of an additional fifth digit, switched on by transistor VT9 based on a signal at pin RC3 of the microcontroller. LED HL4 serves to indicate that the hair dryer is turned on, and HL5 is a backup LED, it is supposed to be used when improving the unit. LEDs HL6-HL11 form a discrete scale, turning on one at a time and showing the installed this moment power level of the soldering iron heater (or hair dryer, if it is turned on) in steps of 1/6 of full power. Higher power corresponds to an LED with a lower position number.

As U2 - a converter of AC mains voltage 220 V to DC 24 V - a ready-made switching power supply PS-65-24 with a power of 65 W was used. The oxide capacitor C5 is placed next to it and from this capacitor separate wires go to each 24 V voltage consumer. To obtain 12 V voltage from it, a pulsed step-down DC-to-DC converter is used on the MC33063 (DA2) chip, similar to those described in and. The voltage divider R17R19 is selected so that the output of the converter maintains a voltage of 12 V. Its presence is indicated by the glow of the HL2 LED. Next linear integral stabilizer DA3 brings the voltage to 5 V required to power the microcontroller DD1.

The 220 V mains voltage is supplied to the power supply U2 when the SB1 button is pressed. After initialization, the microcontroller program sets its output RE0 (pin 8) to a high logical level, which opens transistor VT4. Capacitor C9 ensures that at the moment the transistor opens, a full voltage of 12 V is supplied to the relay winding and its reliable operation. Upon completion of charging the capacitor, the current through the winding is reduced to a value limited by resistor R23, which only ensures that the relay armature is kept in the actuated state. The HL3 LED indicates that voltage is applied to the relay coil.

The activated relay K1 with its contacts K1.1 bypasses the SB1 button. Now you can release it, the power of the control unit will remain on until the microcontroller closes transistor VT4.

After turning on the power, an inscription with the program version number briefly appears on the HG1 indicator and sounds sound signal. The mode of working with a soldering iron is turned on, which smoothly heats up to the temperature set in previous work sessions and recorded in the EEPROM of the microcontroller. The current temperature value is displayed on the HG1 indicator, and the level of power supplied to the soldering iron is displayed using LEDs HL6-HL11.

To prevent thermal shock, the power level is limited to 40% of the maximum until the temperature reaches 100 °C, and to 80% in the range of 100...300 °C. This increases the time it takes to reach operating temperature, but extends the service life of the soldering iron. Once the set temperature is reached, it stabilizes at that level. By rotating the S1 encoder knob, the temperature can be changed.

When you press the SB3 button, the HL4 LED turns on, the soldering iron is switched to a gentle mode (its temperature drops to 150 ° C), the hair dryer fan turns on, and then its heater. The temperature of the air flow from the hair dryer increases according to an algorithm similar to heating a soldering iron. The desired temperature is set by rotating the encoder knob S1. After pressing this knob once, you can rotate it to adjust the intensity of the air flow.

By pressing the SB3 button again, the heater of the hair dryer is turned off, and the soldering iron is switched to operating mode. The hair dryer fan will continue to operate until the air flow temperature drops to 60 °C. After that it will be turned off automatically.

When you press the encoder button successively, the HG1 indicator displays the names of the following parameters in turn:

AIR - intensity of air flow of the hair dryer (only when it is turned on);

StA0 - coefficient A0 for a soldering iron;

StA1 - coefficient A1 for a soldering iron;

FtA0 - coefficient A0 for a hair dryer;

FtA1 - coefficient A1 for a hair dryer.

Coefficients A0 and A1 are used by the microcontroller program to determine the temperature of the soldering iron tip or the air flow supplied by the hair dryer based on the number N obtained as a result of the ADC operation, which linearly depends on the thermoEMF of the corresponding thermocouple. Temperature T (in degrees Celsius) is calculated using the formula

When you rotate the encoder knob, the value of the selected parameter changes and is displayed on the indicator in a flashing form instead of its name. If you do not rotate or press the knob for several seconds, the indicator will return to the current value of the temperature of the soldering iron or the air flow from the hair dryer.

When you press the SB5 button, the microcontroller saves the current parameter values ​​in non-volatile memory and turns off the heaters of the soldering iron and hair dryer. If the hair dryer was active at this moment, blowing the heater with cold air continues until the flow temperature at its outlet drops to 60 °C, after which the microcontroller sets low level voltage at output RE0. Transistor VT4 closes and relay K1 opens its contacts, disconnecting the control unit from the power supply.

Button SB4 is a backup button. It can be used to improve and expand the functionality of the block.

Instead of the PS-65-24 (U2) power supply, any other switching or transformer mains power supply unit can be used for the soldering station control unit, which provides a stabilized DC voltage of 24 V with a load current of at least 2 A. If you use the unit as U2, Having, in addition to a +24 V voltage output, another +12 V voltage with a permissible load of at least 300 mA, the step-down converter on the MC33063AP1 chip can be excluded from the device. If this converter is used, the MC33063AP1 chip in it can be replaced with MC34063AP1.

Relay K1, optocoupler U1 and triac VS1 are located on a separate printed circuit board. This is necessary to maximize the distance of low-voltage circuits from those energized by 220 V.

A WJ112-1A relay with a 12 V winding is used. Instead, another one with contacts designed for switching an alternating voltage of at least 250 V at a current not less than that consumed by the control unit and hair dryer heater is suitable. If a relay with a rated coil voltage of 24 V is selected, it must be powered from a source of this voltage.

Instead of the MOC3063 optocoupler, you can use any dinistor that can directly control a triac with permissible voltage not lower than 600 V. In order not to increase the level of interference created in the network, it is advisable to choose a replacement optocoupler with a unit for monitoring the transition of the voltage applied to its output through zero.

The BT138X-600 triac in an insulated plastic case can be replaced with a BT138-600 similar in parameters in a conventional TO-220 case with a metal flange or another that can withstand a voltage of at least 600 V when turned off, and a current of at least 6 A when turned on. The triac works in a control unit without a heat sink.

Buttons SB1, SB3-SB5 are of the DS-502 type, but they can be replaced with others that are convenient for installation. Button SB1 must be designed for AC voltage between open contacts of at least 250 V and withstand the inrush current of the switching power supply U2. You should definitely make sure that the selected unit has a thermistor that limits the inrush current. If it is absent, be sure to install a thermistor with a cold resistance of 5...10 Ohms in series with the SB1 button or in the power supply itself (for example, SCK-052 or SCK-101).

The encoder used is ED1212S-24C24-30F - with mechanical contacts giving 12 pulses per revolution and a built-in button. Another one can be used, including an optical encoder with the corresponding power supply units and the formation of output pulses.

The RL-F5610GDAW/D15 indicator can be replaced by any other LED with common cathodes of elements of each category, for example KEM-5641.

The control unit uses a commercially available Z-1 housing. Its front panel was replaced with a transparent one cut from sheet polycarbonate. On the reverse side, a transparent film for inkjet printing is pressed against it, on which the design of the front panel is printed.

This panel has buttons SB1, SB3-SB5 and connector sockets for connecting a soldering iron (X2 - five-pin DIN 41524 or ONTs-VG-4-5/16-R, also known as SG-5) and a hair dryer (X3 - eight-pin DIN 45326 or ONTs-VG-5-8/16-R). Descriptions of these connectors can be found in. Behind the transparent panel there is a board with an HG1 indicator and LEDs. Appearance The block together with a soldering iron and a hair dryer is shown in Fig. 4.

If the soldering station control unit is assembled correctly and the microcontroller is programmed, it starts working immediately; you only need to set the coefficients A0 and A1 for the soldering iron and hair dryer. To do this, immediately after turning on the power, use the encoder to set the temperature below room temperature on the HG1 indicator. Next, by pressing the encoder button, select the setting of the coefficient A0 for the soldering iron and, by changing it, ensure that the indicator shows the current temperature in the room. Then, moving on to setting the coefficient A1, by rotating the encoder knob, its value is 1.0 on the indicator.

After this, a thermocouple or other sensor of a standard temperature meter is attached to the soldering iron tip. It is advisable to isolate the tip with an external sensor attached to it from environment any poorly conductive heat material, while complying with the requirements fire safety. Using an encoder, they set on the HG1 indicator some not very high temperature(for example, 100 °C) and wait until the readings of the standard thermometer stabilize. If it shows a temperature higher than the set one, the value of coefficient A1 should be reduced, otherwise it should be increased. By selecting this coefficient, it is ensured that the difference between the temperature measured by the reference thermometer and the set temperature does not exceed 5 °C.

The temperature of the tip should not be allowed to rise above 300...400 oC (according to a standard thermometer). If this happens, you should check the voltage at the output of op-amp DA1.2 and, if necessary, select its gain so that at the highest possible temperature of the soldering iron, the output voltage of the op-amp does not exceed the reference voltage of the microcontroller ADC. Finally, it is recommended to set the tip temperature at which most soldering is expected to be performed, and reselect the A1 coefficient.

The coefficients A0 and A1 for a hair dryer are selected in the same way. In this case, the air flow intensity is set to medium and the temperature sensor of a standard thermometer is placed at a distance of 1 cm from the hair dryer nozzle. After selecting all the coefficients, the soldering station is ready for use.

With the described control unit, you can use any soldering iron with a built-in thermocouple and a low-voltage heating element. The hairdryer must have a heating element with a voltage of 220 V and also with a built-in thermocouple. You should also make sure that the hair dryer fan is designed to operate on 24 V. Please note that the colors of the insulation of the wires going from the hair dryer to the connector, indicated in the diagram in Fig. 3 are not standardized and may vary.

Sometimes you can find soldering irons and hair dryers with thermistors as temperature sensors. They cannot be used with the described control unit without making significant changes to its measuring path (nodes on the DA1 chip) and adjusting the microcontroller program.

An alternative application of the considered design can be a two-channel temperature meter of any objects with sensors in the form of thermocouples and a single-channel temperature controller. If temperature adjustment is not required, then after setting the coefficients A0 and A1, the encoder can be removed.

The control unit microcontroller program can be downloaded

Literature

1. PS-65 series 65W Single Output Switching PowerSupply. - http://www.meanwell.com/search/ps-65/ps-65-spec.pdf.

2. MC34063A, MC33063A, SC34063A, SC33063A, NCV33063A 1.5 A, Step-Up/Down/ Inverting Switching Regulators. - http://www.onsemi.com/pub_link/Collateral/MC3 4063A-D.PDF.

3. Biryukov S. Voltage converters on the KR1156EU5 microcircuit. - Radio, 2001, No. 11, p. 38-42.

4. DIN connector. - http://ru.wikipedia.org/wiki/Connector%20DIN.

Publication date: 31.10.2013

Readers' opinions

• Sergey / 11/19/2014 - 18:58
  How can I contact the author of this article!?
• Sergey / 05.11.2014 - 18:34
  what program to open the program please tell me
• Vladimir / 09.27.2014 - 17:40
  There is a simpler and cheaper scheme, with open source (from the guys from Moscow Higher Technical School).

There are a lot of diagrams of various soldering stations on the Internet, but they all have their own characteristics. Some are difficult for beginners, others work with rare soldering irons, others are not finished, etc. We focused specifically on simplicity, low cost and functionality, so that every novice radio amateur could assemble such a soldering station.

What is a soldering station for?

An ordinary soldering iron, which is connected directly to the network, simply heats constantly with the same power. Because of this, it takes a very long time to warm up and there is no way to regulate the temperature in it. You can dim this power, but achieving a stable temperature and repeatable soldering will be very difficult.
A soldering iron prepared for a soldering station has a built-in temperature sensor and this allows you to apply maximum power to it when heating up, and then maintain the temperature according to the sensor. If you simply try to regulate the power in proportion to the temperature difference, then it will either warm up very slowly, or the temperature will fluctuate cyclically. As a result, the control program must necessarily contain a PID control algorithm.
In our soldering station, we, of course, used a special soldering iron and paid maximum attention to temperature stability.

Specifications

1. Powered by 12-24V DC voltage source
2. Power consumption, when powered 24V: 50W
3. Soldering iron resistance: 12ohm
4. Time to reach operating mode: 1-2 minutes depending on supply voltage
5. Maximum temperature deviation in stabilization mode, no more than 5 degrees
6. Control algorithm: PID
7. Temperature display on a seven-segment indicator
8. Heater type: nichrome
9. Temperature sensor type: thermocouple
10. Temperature calibration capability
11. Setting the temperature using the ecoder
12. LED to display soldering iron status (heating/operating)

Schematic diagram

The scheme is extremely simple. At the heart of everything is the Atmega8 microcontroller. The signal from the optocoupler is fed to an operational amplifier with adjustable gain (for calibration) and then to the ADC input of the microcontroller. To display the temperature, a seven-segment indicator with a common cathode is used, the discharges of which are switched on through transistors. When rotating the BQ1 encoder knob, the temperature is set, and the rest of the time the current temperature is displayed. When turned on, the initial value is set to 280 degrees. Determining the difference between the current and required temperature, recalculating the coefficients of the PID components, the microcontroller heats up the soldering iron using PWM modulation.
To power the logical part of the circuit, a simple 5V linear stabilizer DA1 is used.

Printed circuit board

The printed circuit board is single-sided with four jumpers. The PCB file can be downloaded at the end of the article.

List of components

To assemble the printed circuit board and housing, you will need the following components and materials:

1. BQ1. Encoder EC12E24204A8
2. C1. Electrolytic capacitor 35V, 10uF
3. C2, C4-C9. Ceramic capacitors X7R, 0.1uF, 10%, 50V
4. C3. Electrolytic capacitor 10V, 47uF
5. DD1. Microcontroller ATmega8A-PU in DIP-28 package
6. DA1. L7805CV 5V stabilizer in TO-220 package
7. DA2. Operational amplifier LM358DT in DIP-8 package
8. HG1. Seven-segment three-digit indicator with a common cathode BC56-12GWA. The board also provides a seat for a cheap analogue.
9. HL1. Any indicator LED for a current of 20 mA with a pin pitch of 2.54 mm
10. R2,R7. Resistors 300 Ohm, 0.125W - 2 pcs.
11. R6, R8-R20. Resistors 1kOhm, 0.125W - 13pcs
12. R3. Resistor 10kOhm, 0.125W
13. R5. Resistor 100kOhm, 0.125W
14. R1. Resistor 1MOhm, 0.125W
15. R4. Trimmer resistor 3296W 100kOhm
16. VT1. Field effect transistor IRF3205PBF in TO-220 package
17. VT2-VT4. Transistors BC547BTA in TO-92 package - 3 pcs.
18. XS1. Terminal for two contacts with pin spacing 5.08 mm
19. Terminal for two contacts with pin spacing 3.81 mm
20. Terminal for three contacts with pin spacing 3.81 mm
21. Radiator for stabilizer FK301
22. Housing socket DIP-28
23. Housing socket DIP-8
24. Power switch SWR-45 B-W(13-KN1-1)
25. Soldering iron. We will write about it later
26. Plexiglas parts for the body (cutting files at the end of the article)
27. Encoder knob. You can buy it, or you can print it on a 3D printer. File for downloading the model at the end of the article
28. Screw M3x10 - 2 pcs.
29. Screw M3x14 - 4 pcs.
30. Screw M3x30 - 4 pcs.
31. Nut M3 - 2 pcs.
32. M3 square nut – 8 pcs
33. M3 washer - 8 pcs
34. M3 locking washer – 8 pcs
35. Assembly will also require installation wires, zip ties and heat shrink tubing.

This is what a set of all the parts looks like:

PCB installation

When assembling a printed circuit board, it is convenient to use the assembly drawing:

The installation process will be shown and commented on in detail in the video below. Let us note only a few points. It is necessary to observe the polarity of electrolytic capacitors, LEDs and the direction of installation of microcircuits. Do not install microcircuits until the case is completely assembled and the supply voltage has been checked. ICs and transistors must be handled carefully to avoid damage from static electricity.
Once the board is assembled, it should look like this:

Housing assembly and volumetric installation

The block wiring diagram looks like this:

That is, all that remains is to supply power to the board and connect the soldering iron connector.
You need to solder five wires to the soldering iron connector. The first and fifth are red, the rest are black. You must immediately put a heat-shrinkable tube on the contacts, and tin the free ends of the wires.
The short (from the switch to the board) and long (from the switch to the power source) red wires should be soldered to the power switch.
The switch and connector can then be installed on the front panel. Please note that the switch may be very difficult to engage. If necessary, modify the front panel with a file!

The next step is to put all these parts together. There is no need to install the controller, operational amplifier or screw on the front panel!

Controller firmware and setup

You can find the HEX file for the controller firmware at the end of the article. The fuse bits should remain factory, that is, the controller will operate at a frequency of 1 MHz from the internal oscillator.
The first power-up should be done before installing the microcontroller and operational amplifier on the board. Apply a constant supply voltage from 12 to 24V (red should be “+”, black “-”) to the circuit and check that there is a 5V supply voltage between pins 2 and 3 of the DA1 stabilizer (middle and right pins). After this, turn off the power and install the DA1 and DD1 chips into the sockets. At the same time, monitor the position of the chip key.
Turn the soldering station back on and make sure all functions are working correctly. The indicator displays the temperature, the encoder changes it, the soldering iron heats up, and the LED signals the operating mode.
Next, you need to calibrate the soldering station.
The best option for calibration is to use an additional thermocouple. It is necessary to set the required temperature and control it on the tip using a reference device. If the readings differ, then adjust the multi-turn trimmer resistor R4.
When setting, remember that the indicator readings may differ slightly from the actual temperature. That is, if you set, for example, the temperature to “280”, and the indicator readings deviate slightly, then according to the reference device you need to achieve exactly a temperature of 280°C.
If you don’t have a control measuring device at hand, you can set the resistor resistance to about 90 kOhm and then select the temperature experimentally.
After the soldering station has been checked, you can carefully install the front panel so that the parts do not crack.

Video of work

We made a short video review

…. and a detailed video showing the assembly process:

I thought for a long time whether to write an article about this homemade product or not. On the Internet you can probably count a dozen articles on this scheme. But since, in my opinion, this particular circuit design solution is the most successful, I am sharing the design with you, dear visitors of the Technoreview website. I would like to immediately thank the author of the diagram for the work done, and for the fact that he posted it for public use. The soldering station is quite simple to manufacture and is very necessary in amateur radio practice.

When I first started my journey as a radio amateur, I didn’t think about anything. Soldered with a powerful 60 watt soldering iron. Everything was done with overhead mounting and thick wires. Over the years, having gained a little experience, the tracks became thinner and the details became smaller. Soldering irons of lower power were purchased accordingly. I once purchased a soldering iron from the LUKEY-702 soldering station with a maximum power of 50 watts and a built-in thermocouple. I picked up the diagram for assembly right away. Simple and reliable, with a minimum of parts.

Diagram of a homemade soldering station

Parts list for the circuit:

• R1 - 1M
• R2 - 1k
• R3 - 10k
• R4 - 82k
• R5 - 47k
• R7, R8 - 10k
• R indicator -0.5k
• C3 - 1000mF/50v
• C2 - 200mF/10v
• C - 0.1mF
• Q1 - IRFZ44
• IC4 – 78L05ABUTR

Power diodes B1 are used KD202K. Just suitable for this purpose. To power the MK, I took a small-sized diode assembly B2. E30361-L-0-8-W with a common cathode was used as LED indicators. I also designed my own printed circuit board for my own indicator. It turned out to be double-sided. One-sided could not. Too many jumpers. The board is not the best, but it has been tested and works. I also re-soldered the connector on the soldering iron itself. His standard one is no good. At first, the boozer was not provided on the board. I installed it after, but the board in the archive was fixed.

Soldering station - case manufacturing