Today I will try to tell you about our friend’s project, which I personally enjoy using to this day - this is a soldering station with a hair dryer and a soldering iron on an Arduino controller. I myself am not very versed in radio electronics, but I have the basic concepts, so I will talk more from the point of view of a layman rather than a professional, especially since the author himself has no time to talk in detail about this project.
The main purpose is convenient and high-quality soldering at a soldering station using a soldering iron and a hair dryer. The hair dryer and soldering iron are turned on and off using separate buttons, and can work simultaneously.
The main difference between our soldering iron (and hair dryer) and a regular one is constant temperature control! If I set the temperature to 300 degrees, then exactly this temperature will be maintained on the soldering iron tip with the slightest deviations. This soldering iron does not need to be regularly removed from the socket like a regular one, and it does not need to be plugged back into the socket when it has cooled down. A hairdryer also has the same function.
The station is equipped with an LCD screen that displays the set temperature for the soldering iron and hair dryer, as well as the current measured temperature on these devices. When observing these readings, you can notice that the measured temperature constantly tends to the set temperature and deviates from it only for fractions of seconds and a few degrees. The exception is the moment of switching on, when the device is just heating up.
In addition to the power buttons and screen, there are three more potentiometer knobs on the external panel of the station. They can set the temperature of the soldering iron and hair dryer, as well as the rotation speed of the hair dryer fan. The temperature is measured in degrees Celsius, and the speed of the hair dryer is measured in percentage. At the same time, 0% does not mean the fan is turned off, but simply the minimum speed.
The hair dryer is equipped with a protective blowing function. If you were using a hair dryer and turned it off with the button, the heating element of the hair dryer will turn off, and its fan will continue to rotate, blowing air through the hair dryer until its temperature drops to a safe 70 degrees. To prevent the hair dryer from malfunctioning, do not unplug the station from the outlet until the blowing is complete.
I consider the basis of the device to be a printed circuit board developed and manufactured by comrade Kamik. In the center of this board there is a block in which the Arduino Nano V3 controller is installed. The controller supplies signals to three MOSFET transistors, which smoothly control three loads: the heating elements of the soldering iron and hair dryer, as well as the hair dryer fan. Also on the board there are trimming resistors for setting the thermocouples of the soldering iron and hair dryer, as well as many pads and connectors for connecting a hair dryer and soldering iron (via GX-16 connectors), a screen, buttons for turning on the hair dryer and soldering iron, and potentiometers. Also, a step-down module LM2596 is glued directly onto the board to reduce the voltage from 24V to 5V to power the arduino itself and the LCD screen. The fan and heater of the hair dryer operate from 220V, the soldering iron - from 24V. To power the soldering iron there is a separate power supply 220V->24V, ordered from China. Five-volt consumers are powered by a step-down switch LM2596.
The hair dryer and soldering iron are connected to the soldering station using GX16 connectors with eight and five contacts, respectively. To connect a 220V power cord, a special socket with a built-in switch and fuse is provided.
My friends and I decided to assemble several of these soldering stations at once, so we were able to save on some parts from China due to small wholesale lots: we specifically looked for lots where the parts we needed were sold in 5 pieces and in some cases (for example, potentiometers) - in 20 pieces. As a result, the cost of one station (without housing) was about 40$.
Very often, avid radio amateurs are faced with such a problem as soldering irons that do not meet their requirements, or simply burn out during operation. In addition, the soldering iron tip is not always suitable for micro work and requires adjustments to its diameter.
Today, the situation with commercially available soldering irons is simply catastrophic. Good, high-quality soldering irons are expensive, and cheap Chinese ones burn out during the first day of use.
In order not to waste extra money, you can try to make a soldering station yourself.
A soldering hair dryer is similar to an ordinary household product that is used to dry hair. Its main difference can only be called the operating temperature. It is thanks to the power, which is much greater in a soldering hair dryer, that with the help of this product it is possible to solder various radio components. And also, using this item you can collect diagrams.
Brief description of the device for beginners:
It is because of this that specialists readily use soldering stations. In other words, this semi-professional heating equipment, which includes a welding heating element and a convenient soldering iron, is excellent for soldering small parts. This cool modern soldering station is perfect for painstaking work with electrical circuit blocks and networks. Sometimes, thanks to such a device, you can heat treat small elements. However, you need to know that each model, which is called a soldering gun, is individual in its technical parameters and has a nozzle diameter from 2 to 6 mm. power within 500 watts; maximum fan performance up to 32 liters per minute; and operating temperature up to 550 degrees.
Simple soldering irons are mainly used by beginner radio amateurs. Those who professionally repair equipment, or who simply often have to do soldering, buy special universal soldering stations. But a good soldering unit is expensive these days, and Chinese consumer goods don’t last long.
The way out of the situation is to create a simple soldering station at home based on an Arduino module, which will work flawlessly, performing any tasks of the master. The diagram and drawings of this homemade product are quite simple.
It contains the following details:
To make a soldering station based on Arduino, you will need the following parts: toroidal transformer, triac, diode rectifier, Arduino Pro Mini, MAX6675 chip, capacitor, resistors, 51K potentiometer, compressor.
The contact method of heating the soldering tip is becoming a thing of the past. It is used in classic circuits of universal soldering stations, but is imperfect. This can be noticed by low efficiency, high power consumption, local overheating of the tip at the contact area and other inconsistencies
An induction soldering station eliminates such disadvantages. When high-frequency voltage enters the induction coil, a conventional alternating magnetic field is formed. Since the outer layer of the tip is made of natural ferromagnetic material, during operation the process of magnetization reversal of the element begins, which is accompanied by eddy currents. This leads to a noticeable release of heat energy.
The advantages of the simple induction soldering method are as follows:
Stations equipped with a temperature sensor are significantly cheaper than conventional ones, which makes them accessible to both professionals and amateurs. The accuracy, practicality and reliability of this equipment directly depend on the digital control unit.
The main advantage of a homemade soldering station is its lower cost than that purchased on the market. In addition, by making a soldering iron and a tip for it, you can make them exactly as you need. After all, only you know which devices you have to repair most often, and which tips will come in handy more often.
To make a soldering iron tip you will need the following tools and materials:
The first thing you need to do is make sure that any bent areas on the tube are straightened out and any unevenness is removed. Cut the tube into pieces, adjusting the length with a hacksaw or pipe cutter. When performing these manipulations, protect your hands with special gloves.
To make it convenient to work, cut a piece of wire 16-25 cm long. Then we proceed to making the casing. To do this, take pieces of tube 25x8 mm and make marks every 25 mm.
For casings, experts recommend using scraps of tubes 2.5 cm long and 8 mm in diameter (5/16 inches). Carefully measure the pieces of the required length, make marks on each section after 2.5 cm (with a nail or a sharp hacksaw blade. Using a hacksaw, we saw off the tubes along the mark. This must be done carefully, so that the work is done flawlessly.
Once you have sawed off the top casing, you will have to begin the process of removing small metal “rags” that got inside the tube during sawing. Use a screwdriver to clean the cut area, turning it from time to time and checking the inside of the tube. Don't forget that you don't need to widen the holes. After stripping the tube, take a soldering iron and thread it into the casing. It should fit perfectly, as if you had an original sting in your hands. Having achieved successful fitting, file the casing, smoothing the edges. However, there is no need to overdo it. There is no need for you to grind off an extra piece of material now.
By nickel-plating the tips of your soldering iron, you can not only improve their appearance, but also extend the life of the product. Nickel will be able to protect copper tips from corrosion in the future, and will avoid tin deposits.
On the modern market, nano soldering stations are represented by such models as Encoder and Atmega 8, but their prices are quite high. By making a blowtorch for your own needs with your own hands, you can not only save money, but also make an infrared device that will serve you for a very long time and faithfully. You can also make conductive gas glue or paste yourself for soldering.
I have long wanted a hot-air soldering station, but I was stifled by the toad and depressing portability, because the old Soviet 40-watt soldering iron easily fit in a backpack, and I soldered quite well with it, the last straw was that I ran out of solder and I bought a coil of another one at the nearest stall solder, and for some reason it didn’t melt from the word at all, it just refused, I made a claim to the seller, to which he said, “I’m fine, it’s your soldering iron that’s crap,” I was of course offended, as it worked fine for 25 years and then stopped , well, okay, you still need to solder, I bought another solder at another stall, and again nothing, it just doesn’t melt, I thought about it and went to buy a brand new soldering iron, I turned it on right in the store and checked it, the second solder melts and the drops are flying, I think the heater has been around for many years my favorite soldering iron became unusable, but what’s interesting is that the solder that I bought at the first stall still didn’t melt, as I later found out it starts to melt at 300 degrees.
But another thing came out: the tip of a new-made soldering iron burns out in 10-15 minutes, either because the temperature there is higher or the tip is made of crappy metal, but the point is that I tinned the old soldering iron once and there were no problems during many hours of work, but here’s the soldering It turned from a pleasant pastime into a torment; I constantly had to clean the tip with a steel sponge. 
In general, the time has come to look for a normal soldering iron, but again under the pressure of a toad, and since I’ve already started choosing a soldering iron, a hairdryer would be good, otherwise it’s not very convenient to solder microcircuits with a rose alloy, and repairing a phone, even with a well-sharpened tip, is a tedious and painstaking job.
I looked at different options, but some were too expensive, some were not very flexible, and then I came across this video - Arduino soldering station for $10(and here my inner Jew rejoiced) although the real cost turned out to be more than $25 for components, it is still cheap and I gained a lot of experience working with arduino and microelectronics.
I ordered a bunch of components, which in the end were also not enough and I had to buy more from a radio shop at an inflated price, but I couldn’t bear it anymore, and enduring the pain of using a burning soldering iron, I began to assemble the circuit.
The main elements of the station are bought assembled, namely an arduino, a power supply unit, a soldering iron and a hair dryer, but small things like a hair dryer dimmer and a control transistor had to be dealt with on your own.
First of all, I took up the amplification board for the thermocouple on the LM358N 
The first time I assembled something on a breadboard, I tried to make everything as compact as possible, but it didn’t turn out neatly, the soldering iron was terribly inconvenient... 
Then, at an accelerated pace, I learned the principles of working with seven-segment indicators, after which I realized that the Arduino’s outputs were not enough; I also had to master shift registers. 
Having learned all the intricacies of working with LED displays (it turns out that all the diodes need to be extinguished after each run to avoid the ghousting effect), I realized that I need 2 displays, for a soldering iron and for a hair dryer, and the leads of the arduino are already running out, and then either make a cascade of shift registers or install them in parallel + 2 arduino legs, but I thought what kind of logic would have to be implemented to separately control two displays by sending one sequence of bytes... well, what the hell, in general, I decided to pick up a ready-made display module. 
Of the two options, laziness won, the graphical interface looks cooler, you can draw all sorts of funny things, but I’m too lazy to mess around with this, which is why 16X2, which is simple both in appearance and in learning, suited me better.
The soldering iron control part is an IRFZ44 transistor and a pair of resistors.
But with the hair dryer dimmer the situation is more interesting, there are many implementations: , , , , , , , , , , , , , .
I implemented the simplest circuit with a zero detector. 
Software control of the dimer is based on the library CyberLib.
To begin with, after experimenting with a light bulb, I caught some mistakes, then you can hook up a hairdryer. 
I assembled the circuit on the same breadboard (I have all the elements on separate boards to be modular) between the high-voltage tracks, I cut off the spots from the breadboard so that the chance of breakdown was less. 
Tirak from the light bulb heated up to 32 degrees, from the hair dryer to 70, so I sat him on the radiator from the diode assembly (donor laser printer).
To control the fan, I simply duplicated the soldering iron control circuit (there are a lot of such powerful transistors, but I was too lazy to start a zoo). 
I wanted to make active elements on the beds, but unfortunately there were no 6-pin ones, I had to take what I had and order in reserve from China.
All the necessary modules are ready, now it’s time to put them together, the heart of the entire unit is the Arduino Pro Mini V3 clone, it’s good because it has 4 additional pins (there can never be too many faults).
I figured out the location on the board so that everything would fit. 
I added a speaker (to blink and beep), connectors all from the same printers, a resistor for adjusting the display contrast, and a bunch of resistors for the buttons.
The buttons are series-connected resistors connected to an analog input, by reading which you can distinguish which button is pressed. 
The disadvantage of this approach is that only one button is normally processed at a time, but the advantage is that for a huge number of buttons (8 in the final version) only one Arduino input is used.
Having collected all this stuff on the table, I realized that I needed to think about the case. 
The first version is assembled in a cardboard box, just not on the table. 
And immediately went to the construction store for containers.
What happened to be cut out of plastic was terrible... 
After one fall, the corner cracked and then I had to make another body.
The choice fell on an old CD drive, the drive is old, the walls are thick and strong. 
I drilled holes and covered the bottom with plastic from the packaging.
The front panel is made from a plug from the same case, and there are more hot snot. 
The front panel is quite small, and I had to arrange the controls and connectors very tightly; at first I thought of placing the soldering iron and hair dryer connectors on the sides of the station, but in this case it becomes difficult to access one of the nodes, so the connectors are maximally to the left, then the display and then 2 row of controls, top soldering iron, bottom hair dryer, everything is software configured.
Initially, I thought of making beautiful colored buttons, but I need at least 6 of them, which is quite a lot and there is no room for them, I also rejected the idea with two encoders since the implementation of the code is quite complicated (counting changing levels) and it’s better to spend time on something more useful, I settled on ordinary clock buttons by soldering them on a breadboard, the buttons themselves are short, I used short bolts with a nut from the inside as pushers, it didn’t turn out very smooth, but the click click is quite distinct, as the first implementation will go.
The installed 24-volt fan is more likely to ease the conscience, there are almost no very hot elements inside, only the tire and the diode bridge are heated under load, so the fan is connected in parallel to the hair dryer turbine, and there is a switch (jumper from the same drive) to switch the fan to constant work or turn it off completely.
When the hair dryer is running, you can't hear the fan in the case.
The Arduino is powered by my favorite DC-DC converter (the smaller one). 
It is a little redundant (can provide up to 3 amperes) but there were no alternatives to it, I tried installing micro DC-DC but it got very hot since it is designed for a maximum of 23 volts and operates at the limit, but a 5 volt linear stabilizer will output 19 volts in the heat, which is also too much.
As far as the hardware implementation is concerned, that's probably all, the rest is a matter of firmware, I uploaded all my work to GitHub, including the full diagram in eagle, there are a lot of errors in the code, I'll try to find time and bring the code into a more appropriate form, but at least everything works at this stage, although there are a couple of uncaught bugs that need to be worked on.
Calibration was carried out using a K-thermocouple and a calibration sketch, all tables and sketches are on GitHub, the calibration does not pretend to be ideal, but in the operating ranges + / - it is accurate (when calibrating the soldering iron, one tip burned to hell with excessive temperatures, be careful and calibrate with a tip that no pity).
That's probably all; at the time of writing, the station worked for about 10 hours (mostly on little things) so far without any major complaints.
In this article I want to talk about my version of a soldering station based on a microcircuit ATmega328p, which is used in arduino UNO. The project was taken as a basis from the website http://d-serviss.lv. Unlike the original, the display was connected using the i 2 c protocol: firstly, I had it, I ordered several pieces on AliExpress for other projects, and secondly, there were more free MK legs that could be used for some other functions. Photo of the display with an adapter for the i 2 c protocol is below.
The temperature of the soldering iron, hair dryer and cooler speed are regulated by encoders:
The soldering iron and hair dryer are turned on and off by pressing the encoder, and after turning it off, the temperature of the soldering iron, hair dryer and cooler speed are stored in the MK memory.
After turning off the soldering iron or hair dryer, the temperature is displayed in the corresponding line until it cools down to 50 0 C. After turning off the hair dryer, the cooler cools it to 50 0 C at 10% speed, which makes it almost silent when turned off.
To power the circuit, a 24V and 9A switching power supply was purchased on Aliexpress, which, as I later realized, was too powerful. It’s worth looking for one with an output current of 2-3 A - this is more than enough, it will be cheaper, and it will take up less space in the case.
To power the circuit, I used a DC-DC converter on LM2596S, connect it to 24V and set the construction resistor to 5 volts.
I also purchased a soldering iron and a hair dryer on aliexpress. It is IMPORTANT to choose them with a thermocouple and not with a thermistor. The hair dryer was chosen from stations 858, 858D, 878A, 878D and 878D, the soldering iron from stations 852D +, 853D, 878AD, 898D, 936B, 937D. If you use a thermistor, the circuit and firmware need to be modified. I bought a set of 5 tips for the soldering iron. The soldering iron was defective; a wire was broken somewhere inside. I had to change it, the cable from the USB extension cord fit well.
You will also need additional connectors GX16-5 and GX16-8 to connect a soldering iron and hair dryer to the device body.
Now the case: I spent a lot of time with the problem of choosing a case; at first I used a metal one from a computer power supply, but later abandoned it, because... There was interference from the UPS, which caused the MK and LCD to freeze. I tried shielding the power supply, main board and display. The MK stopped freezing, but the display periodically showed incomprehensible hieroglyphs. I decided to use a plastic case, all problems with interference went away immediately, I didn’t shield anything. I also decided to purchase the case from the Chinese. I got a little carried away with the dimensions and took what turned out to be a very small one (150 mm x 120 mm x 40 mm), of course I fit everything there, made a special board for it, but on the front panel everything turned out to be too compact, and it’s not very convenient to adjust the hair dryer especially .
The modified circuit and printed circuit board are shown below in the picture; it differs from the original by connecting the display, replacing variable resistors and power buttons with encoders. Also in the diagram I removed the 12 volt stabilizer, because... My hair dryer runs on 24V, and I removed the 5-volt stabilizer, replacing it with a DC-DC converter.
The printed circuit board was made in the classical way - tinned with rose alloy in a solution of citric acid.
I placed the triac on a small radiator, power mosfets without a radiator, because No heating was noticed behind them. The pins had to be removed due to poor contact; the wires were soldered directly to the board. I recommend using multi-turn variable resistors for smoother temperature adjustment.
The microcontroller was flashed via Arduino UNO, we connected the MK according to the classical scheme: 1 MK pin to 10 Arduino pin, 11 MK pin to 11 Arduino pin, 12 MK pin to 12 Arduino pin, 13 MK pin to 13 Arduino pin, 7 and 20 pins to + 5 volts, 8 and 22 to GND, to 9 and 10 we connect 16 MHz quartz. The connection diagram is below.
Connection diagram
All that remains is to program the MK.
1) Go to the website https://www.arduino.cc/en/main/software, selecting your OS, download the ARDUINO IDE program, and then install it.
2) After installation, you need to add libraries from the archive; to do this, in the program, select Sketch - Connect library - Add.ZIP library. And we connect all the libraries one by one.
3) Connect the Arduino UNO and the MK connected to it to the computer via USB; the first time you turn it on, the necessary drivers will be installed.
4) Go to the program File – Examples – ArduinoISP – ArduinoISP, in the Tools section, select our board and the virtual port to which the Arduino is connected, then click upload. With these actions we turn our Arduino into a full-fledged programmer.
5) After loading the sketch into the Arduino, open the sketch from the archive, select Tools - write bootloader. Of course, we don’t need the bootloader itself in the MK, but with these actions the fuses will be flashed into the MK and our microcontroller will operate from an external quartz at a frequency of 16 MHz.
To make it easier to understand the process of building a soldering station, you need to understand the functional purpose of the main components.
This processor, installed on a small printed circuit board, has a certain amount of memory. Holes are made around the perimeter of the board, and contact panels are installed for connecting a wide variety of electrical elements. These can be LEDs, sensors of various designs and purposes, relays, electromagnetic locks and much more that operate from power and are controlled by electrical signals. In our case, it will be a soldering station assembled on Arduino.
The peculiarity of the Arduino processor is that it is easily programmed to control connected devices according to an established algorithm. This allows you to independently design automatic control systems for household electrical appliances and other electrical elements.
For working with printed circuit boards of electronic circuits, models of Mosfet soldering irons, made in China with handles of the 907 A1322 939 series, are in great demand among consumers; they are inexpensive, reliable and convenient.
Characteristics:
In this mode of warming up and maintaining temperature, the control devices will switch a current of 2-3 A, but this requires an appropriate power supply.
Note! Some soldering iron designs have a thermocouple as a temperature sensor; such options are not suitable; there must be a thermistor (resistance). You must carefully read the technical documentation and consult the sellers when purchasing.
There are 5 wires in the soldering iron connector:
You can determine the purpose of the wires with a multimeter by measuring the resistance between the wires from a temperature sensor of 45-60 Ohms. The resistance of the heating element is several ohms. In this way, you can distinguish a thermocouple from a sensor and a heating element; its resistance is several ohms and when measuring, if you swap the probes, the readings will differ. The latest models are usually standardized: red-white - sensor wires, black and blue - from the heater, green - grounding. The mating part for the soldering iron cord connector is supplied as a kit; if necessary, both components of the connector are sold in radio parts stores.
Some craftsmen use power supplies from a PC; for 12V they use adapters to increase the voltage to 24V. In these cases, the control circuit works normally, but there are problems of long heating due to low current.
It is more reliable to use industrial products; the 24V 60W Venom Standart is ideal, which provides a current for a load of 2.5 A. It has small dimensions and a durable metal plate housing, easily mounted in a common housing for a soldering station with Arduino.
The proven and reliable Flex Link scheme is widely used by many craftsmen. It is relatively simple and has accessible elements; novice amateurs are able to assemble such a circuit with their own hands.
In addition to the Arduino circuit (UNO), power supply and soldering iron, some more elements will be needed as part of the overall circuit:
There are several options for powering the Arduino and individual circuit elements; you can set the output of the stabilizer to 5V and feed it to the Arduino input via USB.
Another option is to install 12V at the output and feed it through a classic cylindrical connector. 5 volts for the circuit can be taken from the stabilizer built into the Arduino.
In our case, the Arduido board is used as a controller, the control buttons are connected from a +5V power supply through a 10kOhm resistance. A three-digit (each digit has 7 segments) LED indicator allows you to clearly monitor the temperature of the soldering iron.
Important! When connecting an indicator to a board, you must definitely understand its characteristics; manufacturers make different models. It is important what currents the segment LED can withstand, and which pin corresponds to which segment. Successful pinout of contacts depends on correct understanding of the design.
In our case, the segments are connected through 100 Ohm resistances, Pinout of contacts occurs in the following sequence:
Anodes:
Cathodes:
To simplify, the buttons are connected to analog pin A3, A2, and the memory and processor speed are sufficient to note this in the program. On the Arduino UNO board, it is difficult for amateurs who do not have sufficient practical experience to identify the digital pins: 14, 15, 16.
To ensure that the heating element does not overheat at the maximum permissible temperature, the circuit must automatically control the heating process in PWM modulation mode. At the initial stage, 24V is turned on at full power to quickly reach the set temperature. After reaching the set temperature value, the power is reduced to 30-45% with minimal deviation. For example, at 10 °C from the set temperature, the soldering iron will turn off or turn on depending on whether the temperature is higher or lower than the set one, this mode allows you to use 30-35% of the power to maintain the soldering station in operating mode, the inertia of overheating is removed.
To maintain this mode by the circuit, a simple program is written and the processor is flashed. Writing programs requires detailed consideration in a separate article. When there are problems, you can turn to specialists who, for Arduino blocks, will write a program in a few minutes that sets the operating algorithm of the controller for the soldering station. Many sites publish various options for using Arduino, presenting circuit diagrams, printed circuit board options and software. You can buy a program for 1-5 dollars, an Arduino with a processor stitched for a given circuit with a specific algorithm, and assemble the circuit yourself. On this site http://cxem.net/programs.php you can order the production of a printed circuit board, Arduino with a firmware program for an order of $5. On this site, calculations are made, a diagram is drawn up, all the necessary parts are selected and sent to the customer as a kit with a description of the assembly process. As a do-it-yourself designer, the customer has the opportunity to evaluate his abilities, choose what he will make with his own hands, what he will buy and assemble the station himself.
The peculiarity of this option is that the soldering station on Arduino is made on separate blocks. Printed circuit boards (blocks) are easily placed in a common housing; individual elements, such as an LED indicator, a connector for connecting a soldering iron, and buttons are displayed on the front panel.
On a separate board you can place additional elements, the IRFZ44 transistor, the LM358N operational amplifier, with all the capacitors, resistances and a connector for turning on the soldering iron. All connections between blocks are made according to the diagram through connectors.
This example considers a specific assembly option with certain elements. There are various power supplies, stabilizers, Arduino, indicators and other elements; when assembling, it is imperative to take into account the compatibility of parameters changes in pinout and programming. But the general algorithm for selecting elements and checking and writing a control program remains the same.
