Soldering station for atmega16. DIY digital soldering station on ATMega8

A two-channel soldering station, with a soldering iron and a hair dryer working simultaneously, was developed by Pashap3 (see Radiokot for details) and made on ATMEGA16 with a 1602 indicator and an encoder. I made the SMPS for the soldering station on TOP250.

Assembled without errors and from serviceable parts, the PS works perfectly, maintains a temperature of +- 1 g, thanks to the author!

PS scheme

The amplifiers can be made according to one of the circuits or similar ones; I assembled them on the LM358.

Thermocouple amplifier

Thermal compensation for thermocouple

Amplifier for soldering iron thermistor

The SMPS is based on the circuit

Inside the station

PS setup:
1. We perform calibration for the first time with the heaters turned off, set the temperature of the soldering iron and hair dryer,
displayed on the display, equal to or slightly higher than room temperature;
2. Connect the heaters, turn on the machine again with the button pressed to force the hair dryer on and enter
mode for limiting the maximum power of the hair dryer,the temperature is programmed to be 200 degrees and the hair dryer motor speed is 50%,
by turning the encoder knob we increase or decrease the maximum power of the hair dryer heater,
determine at what minimum possible value the temperature of the hair dryer will reach and maintain 200g,
in the same menu you can perform more accurate calibration,
although it is better to calibrate at a temperature of 300-350, the result will be more accurate;
3. Press the encoder button and go to the mode for limiting the maximum power of the soldering iron (the same as a hair dryer);
4. Press the encoder button to go to the main menu: by default, the soldering iron is turned off, which corresponds
the inscription "SOLD OFF" turn on the soldering iron with the button (the temperature is saved from the last use)
by turning the encoder knob we change desired temperature(depending on the rate at which the knob is turned, the temperature changes
by 1 or 10g) upon reaching the set temperature, the buzzer will give a short “peak”;
5. Press the encoder button to go to the sleep timer menu, set the desired time in minutes max to 59, press the button
encoder and return to the soldering iron menu;
6. Remove the hair dryer from the stand or press the button to force the hair dryer to turn on and go to the hair dryer temperature menu
(if the soldering iron is turned on, it continues to maintain the set temperature)
by turning the encoder knob, I change the desired temperature (depending on the rate of rotation of the knob, the temperature will change
by 1 or 10g) upon reaching the set temperature, the buzzer will give a short “peak”,
press the encoder button to go to the menu for setting the hair dryer speed from 30 to 100%, pressing again returns to
previous menu, in normal mode, when laying on the stand, the hair dryer motor will be at maximum speed until the temperature of the hair dryer
will not fall below 50 degrees;
7. The set temperature is displayed for the first 2 seconds after the last turn of the encoder; the rest of the time it is real;
8. 30,20,10,3,2,1 seconds before the end of the sleep timer, a short single “peak” sounds and switches to the “SLEEP” mode
the soldering iron and hair dryer heater are turned off, the hair dryer motor will be at maximum speed
until the temperature of the hair dryer drops below 50 degrees, when you turn the encoder knob, the station wakes up;
9. Turning off the ps with a toggle switch - the heater of the soldering iron and hair dryer are turned off, the hair dryer motor will be at maximum speed
The ps continues to work until the temperature of the hair dryer drops below 50 degrees.

I'm attaching my stamps.

Good day to all, dear radio amateurs! I offer everyone a simple diagram of a soldering station with a hair dryer. I've had an idea for a long time to make a soldering station, with my own hands. It was not advisable for me to buy in a store, since I was not satisfied with the price, quality, management, or reliability. After a long search on the Internet, I found, in my opinion, the best and one-of-a-kind circuit using an atmega8 microcontroller and a WH1602 two-line LCD display, with encoder control. The project is new and is not a clone of the same “worn out” schemes; in general, it has no analogues.

Device Features

The station has the following advantages:

1. Settings menu.
2. Two “memory” buttons, that is, two preset temperature conditions for soldering iron and hair dryer.
3. Sleep timer, you can set the timer in the settings.
4. Digital calibration of the soldering iron is also found in the settings.
5. Built on budget components.
6. I designed the printed circuit board for the PC case from the PSU, so there won’t be any problems with the case either.
7. To power the station, you can use the same board from the PC unit, slightly altering it to the required 20-24v (depending on the transformer), fortunately the dimensions of the case allow this. We can shorten the radiators a little, since we only need 24v and 2-3 amperes for power supply and there will be no strong heating of the power transistors and diode assembly.
8. The firmware contains a “Pi” algorithm for regulating the heating of the hair dryer, which provides uniform heating of the hair dryer coil and cuts off IR radiation when the hair dryer is turned on. In general, if you use a hairdryer skillfully, not a single part will be “fried” ahead of time.

Schematic diagram

Initially, in the author's version, the circuit was made entirely on SMD components (including atmega8) and on a double-sided board. It is not possible to repeat it for me, and I think for most radio amateurs. Therefore, I translated the circuit and developed a board based on DIP components. The design is made on two printed circuit boards: the high-voltage part is made on a separate board to avoid interference and interference. The soldering iron is used with a thermocouple, 24v 50w from the "Baku" station.

The hair dryer is from the same company, with a thermocouple as a temperature sensor. It has a nichrome heater with a resistance of about 70 ohms and a 24v “turbine”. The screen displays the temperature: set and actual for the hair dryer and soldering iron, the strength of the air flow of the hair dryer (displayed as a horizontal scale in the bottom line of the screen).

To increase or decrease the temperature and air flow of the turbine: move the cursor by briefly pressing the encoder, and turning left or right sets the desired value. By holding the first or second memory button, you can remember the temperature that is convenient for you and the next time you use it, pressing the memory will immediately heat up to the values ​​​​set in the memory. The hair dryer is started by pressing the "Fen ON" button, which is located on the front panel, but you can display it on the handle of the hair dryer using the wiring going to the reed switch, since it is not used in this station. To switch the hair dryer to sleep mode: you also need to press the “Fen ON” button, this will stop heating the hair dryer, and the hair dryer’s turbine will cool it to the set temperature (from 5 to 200 degrees), which can be set in the settings.

Station assembly

1. We manufacture the main board according to folk recipe " "
2. We drill and tin the finished scarf.
3. We solder in the 7805 stabilizer, shunt capacitors, a jumper under the socket for the MK and the rest of the jumpers, the socket and shunt capacitors near the socket.
4. We connect the 24v power supply, check the voltage after 7805 and on the MK socket. We make sure that there is +5V on pins 7 and 20, and minus 5v on pins 8 and 22, that is, GND.
5. We solder the direct connection between the MK and LCD 1602, which is necessary for the first launch of the circuit. And these are: R1, R2, trimmer (to adjust the screen contrast, there is on printed circuit board), an encoder with buttons S1 and S2 (these components are soldered on the track side).
6. We solder the wires to the screen, 10 wires in total. The contacts on the screen itself: VSS, K, RW - must be connected together using wires.
7. Flashing atmega8. Configuration bytes: 0xE4 - LOW, 0xD9 - HIGH
8. We connect the power, the circuit is in sleep mode. When you briefly press the encoder, the backlight should light up and a greeting message should appear. If this does not happen: look at the 2nd leg of the MK after switching on there should be a stable +5V. If not, look at the atmega8 harness and fuses. If there is +5v - wiring the indicator. If there is a backlight, but no characters, turn the screen contrast adjuster until they appear.
9. After a successful test run: we solder everything except the high-voltage part on a separate board.
10. We launch the station with a soldering iron connected and admire the result.
11. We make a scarf for the high-voltage part of the circuit. We solder the parts.

Starting the soldering station

First start with high voltage part:

1. We connect the thermocouple of the hair dryer and the impeller to the main board.
2. We connect a 220v incandescent lamp, instead of a hair dryer heater, to a high-voltage socket.
3. Turn on the station, start the hair dryer with the "Fen ON" button - the lamp should light up. Turn it off.
4. If it doesn’t “bang” and the triac is not hot (it is advisable to attach it to the radiator) - connect the heater of the hair dryer.
5. We are launching a hairdryer station. We admire the work of the hairdryer. If there is an extraneous sound (squeaking, grinding) in the triac area, select capacitor C3 in the triac snubber, from 10 to 100 nanofarads. But I’ll be honest and say right away - bet 100n.
6. If there is a difference in the temperature readings of the hair dryer, you can correct it with resistor R14 in the op-amp harness.

Replacing parts

Some substitutions of active and not so active components:

• Op-amp - Lm358, Lm2904, Ha17358.
• Field-effect transistors - Irfz44, Irfz46, Irfz48, Irf3205, Irf3713 and the like, suitable for voltage and current.
• Bipolar transistor T1 - C9014, C5551, BC546 and the like.
• Optocoupler MOC3021 - MOC3023, MOC3052 without zero crossing (without zero cross according to the datasheet).
• Optocoupler PC817 - PC818, PC123
• Zener diode ZD1 - any for stabilization voltage from 4.3 - 5.1V.
• I used an encoder with a button from a car radio.
• The capacitor in the triac snubber is required for 400v and 100n!
• LCD WH1602 - look carefully at the location of the contacts when connecting to the main board; it may differ from different manufacturers.
• For food the best option there will be a stabilized power supply at 24V 2-4A, from one large eastern store or a converted ATX power supply. Although I used 24V 1.2A from the printer, it gets a little warm when using a soldering iron, but it’s enough for me. At worst, a transformer with a diode bridge, but I don’t recommend it.

Station body

I have a PC case from a PSU. The panel is made of plexiglass; when painting, it is necessary to leave a window for the screen by gluing masking tape on both sides. The body is painted with one coat of primer and two coats of matte black spray paint. The soldering iron uses a Soviet five-pin plug from a tape recorder. The hair dryer is not disconnected; it is connected directly to the main board with pins. The soldering iron socket, hair dryer cord and power cord are located on the rear wall of the case. The front panel contains only controls, a screen, a power switch and an indicator for the hair dryer. My first design was with a panel made of textolite, with etched inscriptions, but unfortunately there are no photos left. The archive contains drawings of printed circuit boards, a drawing of a panel, a diagram in Splan and firmware.

Video

P.S. The station is called " Didav" is the pseudonym of the person who created the circuit and firmware for this device. Happy soldering to everyone without "snot". Addition on the circuit and firmware. Especially for the site - Akplex.

Discuss the article HOT-AIR SOLDERING STATION "DIDAV"

Hi all! I'll start with a little background. Once upon a time I was working on a project called “Automatic Caller” for my educational institution. At the last moment, when the work was nearing completion, I calibrated the device and corrected the jambs. In the end, one of my mistakes burned the chip on the programmer. Of course, it was a little disappointing, I only had one programmer, and the project needed to be completed faster.

At that moment I had a spare SMD chip for the programmer, but you couldn’t unsolder it with a soldering iron. And I started thinking about purchasing a soldering station with a hot air gun. I went to the online store, saw the prices for soldering stations, and was amazed... The poorest and cheapest station at that time cost about 2800 UAH (more than $80-100). And good, branded ones are even more expensive! And from that moment I decided to take on the next project of creating my own soldering station from scratch.

For my project, the microcontroller of the AVRATMega8A family was taken as the basis. Why pure Atmegu and not Arduino? “Mega” itself is very cheap ($1), but ArduinoNano and Uno will be much more expensive, and I started programming on MK with “Mega”.

Okay, enough history. Let's get down to business!

To create a soldering station, the first thing I needed was the Soldering Iron itself, the Hot Air Gun, the Housing, and so on:

I bought the simplest soldering iron YIHUA – 907A ($6) which has a ceramic heater and a thermocouple for temperature control;

Soldering gun from the same company YIHUA ($17) with a built-in turbine;

“Case N11AWBlack” ($2) was purchased;

LCD display WH1602 for displaying temperature and status indicators ($2);

MK ATMega8A ($1);

A pair of micro toggle switches ($0.43);

An encoder with a built-in clock button - I picked it out from somewhere;

Operational amplifier LM358N ($0.2);

Two optocouplers: PC818 and MOC3063(0.21 + 0.47);

And the rest of the various loose stuff that I had lying around.

And in total the station cost me about $30, which is several times cheaper.

The soldering iron and hair dryer have the following characteristics:

*Soldering iron: Supply voltage 24V, power 50W;

*Soldering Hair Dryer: Spiral 220V, Turbine 24V, Power 700W, Temperature up to 480℃;

A not too sophisticated, but, in my opinion, quite good and functional circuit diagram was also developed.

Schematic diagram of the Soldering Station

Station power supplies

A 60W step-down transformer (220V-22V) was taken as a source for the soldering iron.

And for the control circuit, a separate power source was taken: a charger from a smartphone. This power supply has been slightly modified and now it produces 9V. Next, using the EH7805 step-down voltage stabilizer, we lower the voltage to 5V and supply it to the control circuit.

Management and control

To control the temperature of the Soldering Iron and Hair Dryer, we first need to take data from the temperature sensors, and this will help us operational amplifier L.M.358 .Because The EMF of the TCK thermocouple is very small (several millivolts), then the operational amplifier removes this EMF from the thermocouple and increases it hundreds of times to perceive the ADC of the ATMega8 microcontroller.

Also, by changing the resistance of the trimming resistor R7 and R11, you can change the gain of the feedback loop, which in turn, you can easily calibrate the temperature of the soldering iron.

Because addiction optocoupler voltage from soldering iron temperature u=f(t) is approximately linear, then calibration can be done very simply: put the soldering iron tips on the thermocouple of the multimeter, set the multimeter to the “Temperature measurement” mode, set the temperature at the station to 350℃, wait a couple of minutes until the soldering iron heats up, and start comparing temperature on the multimeter and the set temperature, and if the temperature readings differ from each other, we begin to change the gain on the feedback (with resistors R7 and R11) up or down.

We will use a soldering iron to control the power field-effect transistor VT2 IRFZ44 and optocoupler U3 PC818 (to create galvanic isolation). Power is supplied to the soldering iron from a 60W transformer, through a 4A diode bridge VD1 and a filter capacitor at C4 = 1000 μF and C5 = 100 nF.

Since the hair dryer is supplied with an alternating voltage of 220V, we will control the hair dryer using Triac VS1 BT138-600 and optocoupler U2 M.O.S3063.

You definitely need to install Snubber!!! Consisting of a resistor R 20 220 Ohm/2W and ceramic capacitor C 16 at 220nF/250V. The snubber will prevent false openings of the triac BT 138-600.

In the same control circuit, LEDs HL1 and HL2 are installed, signaling the operation of the Soldering Iron or Soldering Hair Dryer. When the LED is constantly on, heating occurs, and if they blink, the set temperature is maintained.

Temperature stabilization principle

I would like to draw your attention to the method of adjusting the temperature of the Soldering Iron and Hair Dryer. Initially I wanted to implement PID control (Proportional Integral Derivative controller), but I realized that it was too complicated and not cost-effective, and I just settled on Proportional control using PWM modulation.

The essence of the regulation is as follows: When you turn on the soldering iron, maximum power will be supplied to the soldering iron, when approaching the set temperature, the power begins to decrease proportionally, and when the difference between the current and set temperature is minimal, the power supplied to the soldering iron or hair dryer is kept at a minimum. This way we maintain the set temperature and eliminate the inertia of overheating.

The proportionality factor can be set in program code. The default is "#define K_TERM_SOLDER 20"

"#define K_TERM_FEN 25"

Development of printed circuit board

And appearance station

For the Soldering Station, a small printed circuit board was developed in the Sprint-Layout program and manufactured using the LUT technology.

Unfortunately, I didn’t tin anything, I was afraid that the tracks would overheat and they would peel off from the PCB

First of all, I soldered the jumpers and SMD resistors, and then everything else. In the end it turned out something like this:

I was pleased with the result!!!

Next I worked on the body. I ordered myself a small black case and started racking my brains over the front panel of the station. And after one unsuccessful attempt, I was finally able to make straight holes, insert the controls and secure them. It turned out something like this, simple and concise.

Next on back panel cord connector, switch, fuse were installed

A transformer for a soldering iron was placed in the case, on the side of it there was a power source for the control circuit and in the middle a radiator with a transistor VT1 (KT819), which controls the turbine on the hair dryer. It is advisable to install a larger radiator than mine!!! Because the transistor gets very hot due to the voltage drop on it.

Having collected everything together, the station acquired this internal appearance:

Stands for soldering irons and hair dryers were made from scraps of PCB.

Final View of the Station

Good day everyone! I would like to present a very interesting and useful, in my opinion, project: “Digital soldering station”. On radio engineering sites I have seen many designs and circuits of soldering stations, so I won’t discover America. But I think I will help those who have questions or difficulties figure it out... Because when problems arise when assembling and setting up a device, it is not always possible to read a bunch of forum pages and find the answer to your question. That is why I decided to write this article, to help beginners, and everyone else who is interested in this project, to assemble a really good, working soldering station that will help you in your endeavors. I have nothing against the project on Radio Kota, but it’s better to do it yourself. I took the diagram from the website and did everything else myself. Actually, this is where the similarities end. I collected it not only out of interest in assembling a reliable, inexpensive, small-sized (compact), beautiful-looking device. The fact is that my soldering iron has become unsuitable for soldering, not to mention tinning thin tracks and soldering SMD elements... Scheme of the “Digital Soldering Station”. radiokot.ru/lab/controller/32/05.gif radiokot.ru/lab/controller/32/06.gif Who needs a version of my printed circuit board, write.
Here I am tweaking a version of the printed circuit board from yademon: depositfiles.com/files/23qguj431
Firmware: radiokot.ru/lab/controller/32/02.rar
If you are doing a project, download this document: http://depositfiles.com/files/u3ejohp50
The purpose of the buttons is as follows: The first two buttons are to increase and decrease the temperature by 10 degrees. The other three are memory buttons. When you first turn on the temperature in memory is 250, 300, 350 degrees. The station has protection against forgetting to turn it off. If you have not performed any manipulations with the buttons for 1 hour, the soldering station goes into sleep mode. And if the temperature of the soldering iron is 400 degrees, then after 10 minutes the station will also go into sleep mode. And of course, the beeper beeps when turned on, when buttons are pressed, before going into sleep mode.
Now I will talk about all the elements in detail: For the station, I took a spare soldering iron from Lukey stations. Soldering iron Lukey-SENSOTRONIK with a heater with a built-in thermocouple. It is advisable to take it with a stand, it will be more convenient. Before connecting the soldering iron, you need to determine where you have a thermocouple and where the heating element is. Otherwise, the consequences will be disastrous... It will burn out and you will need to buy a new soldering iron. To determine where you have a thermocouple and where the heating element is, you need to take a tester and measure the resistance. Where there will be less - a thermocouple, where there will be more - a heating element.
A transformer is needed for about 50 watts, or a little more since I have a 50-watt soldering iron. If you apply less to the soldering iron than it “eats”, then nothing will happen to it, but it will take longer to heat up. So it's up to you to decide. Transistor IRFZ44N and linear stabilizer 7805 (5 volts), for convenience, I installed on a common radiator (everything is visible on the printed circuit board) a 6 ampere KBU6M diode bridge, capacitors of 220uf * 25v and 1000uf * 50v. The resistors were all set to 0.125 watts. Solder the ATmega8 chip without a socket without fear, as well as the operational amplifier LM358. A few words about the LM358: You should not mix up the legs of the LM358, otherwise the readings will be incorrect, and as a result you can burn it. The figure shows that 4 leg is ground, 1 is output, 2.3 is input, 8 is power plus. The remaining legs are not used. The position of the legs LM358:

The beeper, who needs it, connects + to the 14th leg of the ATmega8, and - to the ground. And the beeper should also have a built-in generator. Any 7-segment, 3-digit indicator, with both a common anode and a common cathode. I have one with a common cathode. For convenience, the values ​​of the elements are all on the printed circuit board. Also added an indicator of the heating element operation. To avoid all sorts of glitches, temperature fluctuations, etc. never lead the ground to the field switch (soldering iron power supply) through the measuring part! It is better to route the ground from the power supply to the consumers (in the form of a star). To set up the device you will need a thermometer. Without it, it will be difficult to set up... If you are interested, ask questions, I will write.
Here's what happened: Front Panel













Put it all together



Placed it in the case.



The soldering station is working and ready for use.

Now the “Digital Soldering Station” is adapted for spare soldering irons from Lukey 702/898/852D stations (I have the same one) and is ready for further use. All that remains is to calibrate the temperature readings using a thermometer. And then enjoy doing your new projects. Since this project turned out to be interesting not only for me, but also for the other participants, I will write the second part before the “Digital Soldering Station” project, where I will take into account all your questions and wishes... And of course, thank you to everyone for your comments and questions, I’m glad you liked it . Continuation is written in the article “Digital soldering station part 2. (setup and calibration)”