Soldering stations are simply irreplaceable when working with electrical appliances. The main element of the device is considered to be an inductor. Additionally, some stations have special regulators installed that allow you to switch the power of the device. The main parameters should include the threshold voltage, as well as the maximum temperature of the power tool.
Depending on the area of work, the attachments of the devices may vary. Today, the most common are considered to be contact and non-contact modifications. You can assemble them at home, but you should become more familiar with the structure of the station.
Simple station diagram
The soldering station (diagram shown below) includes an inductor with a high pass threshold. Regulators, as a rule, are installed of a linear type, but digital analogues can also be found. Modulators for stations are mainly single-channel. Capacitors are used to change the maximum frequency of a power tool. Special connectors are installed to connect power and grounding cables. If we talk about contact models, then the devices additionally have pulse units. In turn, a non-contact soldering station often includes adapters of different types.
Device with hair dryer
Assembling a soldering station with a hair dryer is quite simple. Most often, these power tools are used to heat the surface. They are ideal for soldering plastic pipes. First of all, to assemble the device, you need to select a microcircuit that is designed to control the device. Most often in this situation, conventional analogues labeled PP20 are used. You can purchase such microcircuits in a store.
A soldering station with a hair dryer operates on phase-type capacitors, and they differ quite significantly in capacity. Next, for assembly, you need to install an inductor next to the microcircuit. It must withstand negative resistance at a maximum level of 2 ohms. All this will allow you to cope with sudden voltage surges. Connectors must be selected based on the existing power cables, as well as grounding. It is best to remove the nozzle from the broken station.
Infrared (IR) modification
The infrared soldering station is quite complex in structure. In this case, only varicap inductors are suitable. Finding them in our time is not difficult. It is best to use two-way modulators for the model. They are designed for three modes. All this will ultimately allow you to change the power of the device. Among other things, it is important to take care of searching for the indicator. Thanks to it, it will be possible to monitor how the IR soldering station works. It is more advisable to install the connector to the electrical network near the inductor.
Hot air stations
In order for a hot air soldering station to work, an inductor coil must have good conductivity. The nominal frequency parameter must be at 44 Hz. Additionally, you should select a high-quality regulator to change the power of the power tool. Contacts are usually used as attachments. To ensure stability of the outgoing wave, resistors are usually installed orthogonally.
Their transmission width on average reaches 55 microns. In order for a soldering station to work well, the modulator for it is selected based on the type of inductor. If you plan to make a medium-power power tool, then the modulator, as a rule, is self-regulating. The lining is used quite rarely. However, to maintain linearity, many experts advise using special operating blocks. Thus, heating of the contact occurs quite quickly. Thanks to this element, the temperature can be increased to a maximum of 200 degrees.
This will make working with steel surfaces very convenient. It is more advisable to select a multi-system connector for grounding. In this case, the negative resistance parameter should not exceed 44 Ohms. Experts do not recommend using three-core cables to supply electricity. In this regard, it is better to trust four-core types.
Analogue modifications
The analog soldering station has good reviews and is very simple in appearance. However, you must be very careful when assembling such devices. The first step is to calculate the threshold voltage in the system. If you work with conventional inductors, they can cope quite successfully with electromagnetic oscillations. It is more advisable to select capacitors for analog stations of the grid type. In turn, resistors are often advised to solder only coaxial ones.
Non-contact models
Today, a non-contact homemade soldering station is in demand. It is most suitable for soldering various plastic surfaces. However, it also copes quite successfully with metal parts. The accuracy of work in this case depends on the maximum frequency of the power tool, as well as the diameter of the nozzle. The connectors for these devices are usually three-electrode.
In turn, capacitorless outputs can be found very rarely these days. Regulators at stations are usually installed with a capacitive varicap. They cope with low-frequency interference very easily. However, it should be taken into account that it is important to mount the coil only on a plastic plate. This way, current will not flow through the bottom of the device.
Contact models
A soldering station of this type can only operate using high-frequency inductors. Additionally, adapters are used in the devices to change the phase. In this case, the threshold voltage of the power tool can reach 50 V. To solve the problem with distortion, experts advise installing capacitorless outputs. In turn, resistors for the station board are selected exclusively of the orthogonal type. All this will allow you to stably maintain the reverse output voltage at 30 V.
The average power consumption of such devices is 2 W. Modulators are used exclusively magnetic. Their current conductivity parameter is on average 44 microns. The degree to which a power tool will distort will ultimately depend on the rate at which the current is generated. Connectors for the station are often selected on an additional expansion board. The device power cable is soldered only near the adapter. The housing for this device can be completely made independently.
How to make a station for lead-free soldering?
Today, many models are manufactured with inductors in which the tetrodes are installed in a belt type. All this suggests that capacitors for power tools should be selected as capacitive ones. The accuracy of the work in this case depends on the nozzle.
If you use a four-core cable, then the maximum frequency parameter of the device can be on average at the level of 66 Hz. The problem with high resistance in the circuit can be solved using pulse resistors. Their conductivity is on average 33 microns. Kenotrons for stations are used quite rarely. However, they can significantly increase the process of phase change. The disadvantage in this case is the excessive load on the capacitors.
Combined modifications
The combined type soldering station is characterized by high soldering precision. Nowadays it is in demand, but it is quite difficult to make this power tool at home. The first problem is finding a multi-channel modulator. Only this type is suitable for power regulation. Microcircuits, as a rule, are installed with the marking PP21. They are capable of operating in half-duplex mode.
In order to increase the power of the device, multi-system conductors are used. In such a situation, you can hope for a maximum temperature of 150 degrees. In turn, the intermediate frequency parameter is on average 23 Hz. Holders for such devices are attached to two-core cables. The maximum negative resistance that they must withstand is 13 ohms.
75V model
A 75 V soldering station (made with your own hands) allows you to work with various alloys. You can also use it to heat surfaces. These stations are ideal for working with plastic materials. In order to assemble them yourself, the inductor should be selected with a high threshold voltage parameter. Adapters for power tools are used quite rarely. You can make the case yourself, or take it from an outdated broken model. Connectors for the power cable must be of a non-linear type.
Many specialists are able to increase the current conductivity in a circuit using broadband transistors. Microcircuits, in turn, can be used of various types. If you assemble devices of medium power, then synchronous capacitors can be used. Their capacitance usually reaches 15 pF. Inductors with optocouplers are used quite rarely. This is due to the fact that they have a short service life. The phase of the output signal of devices depends on the speed of current rectification. When installing connectors, copper semiconductors are used quite often.
100V station
A 100 V soldering station (made by yourself) is most suitable for working with steel surfaces. At the same time, they also cope well with aluminum. The inductor for such devices is selected with a threshold voltage of about 15 V. Multi-system capacitors are most often used. It is quite rare to find open type resistors. In this situation, it is more advisable to think about purchasing cardiode analogues. The minimum current conductivity parameter should be 34 microns.
The degree of distortion of devices depends on the board used. Models marked PP20 are ideal for these stations. However, the modulator for them should be selected separately. Many experts prefer broadband analogues. The maximum negative resistance they can withstand is 35 ohms.
I’ve been wanting a soldering station for a long time, or rather a soldering iron with thermal stabilization. Our soldering irons cost from 3500 rubles, of course it’s expensive and it’s a pity to spend that kind of money. But the soldering irons themselves are sold from the stations and they cost pennies. I bought myself the simplest soldering iron for 500 rubles LUT0035, there is nothing on the Internet about this model, only the soldering iron label says 24V 48V. I brought him home and began to wise up. First of all, I determined the parameters for my soldering station:
— Temperature adjustment 180-360C
— Limiting current consumption for a soldering iron
— Ability to put the soldering iron into standby mode
I defined the parameters and moved on to the schematic
I decided to assemble everything using a PWM TL494; it has everything you need: two error comporators and duty cycle adjustment via the 4th DT pin. I’ve already drawn up the diagram, calculated almost all the wiring around the TL494 and it turned out that it won’t be enough for me. The soldering iron I purchased uses a thermocouple instead of a thermistor to detect temperature, and I had to add a voltage amplifier using an additional LM358 op-amp. In the end, this is the diagram we got:
There's nothing special about the diagram. A voltage of approximately 0.025V at 350C is taken from the Thermocouple and multiplied by an amplifier on LM358 approximately 140 times and divided in half by a divider R6R16
Using variable resistor R8, the required threshold voltage is set on the 2nd leg of the error comporator, equal to approximately 1.75V. Until the potentials between the first and second legs are leveled, the PWM will simulate pulses on the control transistor T1. The transistor took IRF630
Button S1 is installed on the lever-stand for the soldering iron; when the button is closed, the pulse width is limited and current consumption drops by about half, which saves the life of the soldering iron
R12R13 is a divider that determines current consumption and is set to a voltage of 0.2V, which, with a shunt of 0.1 Ohm, maintains a current of approximately 2A. I wanted to limit the current in order to save the life of the soldering iron and transformer
The transformer was taken with two serial windings of 17V each with a common point and made with a filter capacity of 4700 μF. The microcircuits were powered through Kren 7812
To indicate heating, I placed a red LED parallel to the heater.
Well, a couple of photos of the soldering station
In principle, that's all, everything is elementary. The soldering iron works as expected. Heats up from room temperature to 200C in 85 seconds, to 350C in about 215 seconds
I tried to melt refractory solder, which a 25W mains soldering iron could not handle. The station melted without problems, massive tracks and parts of the KU202 type in an iron case are soldered easily
In general, I was pleased with the homemade soldering station. The only thing I’m not happy with is the soldering iron tip, I need to buy something convenient
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Due to the improvement of assembly technologies for various types of products assembled from small metal parts (electronic microcircuits), their manual soldering is causing more and more difficulties.
A homemade soldering gun will allow the operator to cope with the difficulties that arise in these situations without any special complications and eliminate the risks that arise.
So, with the help of a DIY assembly, anyone can install and dismantle parts without the threat of damaging fragile electronic elements located near the soldering site. One of the possible solutions to this problem allows you to make a hot air gun from a soldering iron, which is available in the household kit of any home craftsman.
The typical operating principle is quite simple and is as follows.
The air accelerated by a fan or compressor is pumped into a special channel made in the form of a tube with an electric spiral. Passing through this channel, the flow is heated to the required temperature (from 100 to 800 degrees) and immediately enters a plastic calibrated nozzle, which directs the hot jet onto the workpiece.
In most industrial models of soldering guns, the main parameters of the heated jet (its temperature, direction of movement, and power) can be adjusted within certain limits.
Turbine and compressor type
The circuit diagram of a DIY soldering station can be presented in the form of a main module and a terminal device (thermal hair dryer) that provides heating of the air in the soldering zone.
Before its manufacture, you need to know that according to the method of forming a forced air flow, such devices are divided into turbine and compressor type soldering devices.
In turbine units, air is supplied to the treatment zone by means of a small electric motor with a fan built directly into the hair dryer body. In products of the second class, the air flow is formed using a special compressor located in the main module (controller for a soldering gun).
When choosing the required type of station for soldering small parts, one usually proceeds from an assessment of the following multidirectional factors:
- fan soldering stations are capable of generating a more powerful air flow, which is an obvious advantage of the hair dryer built into them. However, the flow created with their help hardly passes through nozzles that are too narrow;
- compressor hair dryers, on the contrary, are more effective when working with relatively narrow nozzles used when soldering parts located in hard-to-reach places.
The choice of the optimal version of a soldering gun capable of working with a given set of plastic nozzles is carried out taking into account the specific conditions of its operation.
Cooler based
The easiest way to make a hairdryer with your own hands at home is to use the turbine principle of air injection, implemented using any small-sized fan suitable for these purposes.
A soldering hair dryer can be made with your own hands using the cooler that comes with the power supply of any desktop computer.
In this case, the fan is built into the handle of a thermal element made of a fireproof tube with an electric spiral, passing through which the air will heat up and then enter the soldering zone.
The outer part of the soldering gun body must be made airtight, which eliminates the possibility of air being sucked into the surrounding space. To assemble the heater, you will need nichrome wire wound in a spiral on a ceramic tube.
The total length of the winding is selected so that the resistance of the entire wire segment is about 70-90 Ohms.
The individual turns of the spiral wound on a ceramic base should be located at some distance from one another. For safe operation of the heater, this removal should be about 1-2 mm.
From a soldering iron and a dropper
To make a soldered hair dryer with your own hands, you can use a simple soldering iron with the protective casing removed from it.
When taking it as the basis for a future heater, it is necessary to modify the design, which consists of the following:
- First, the tip is removed from the working part of the soldering iron, after which the mica tube with the nichrome winding placed underneath it is completely pulled out of the wooden handle-holder.
- Then the power wires suitable for the heating element are disconnected and also pulled out of the wooden holder, but from the other side.
- After this, a hole of the required size is drilled in the side of the handle, into which the previously disconnected network wire is threaded (towards the working part).
- At the next step of making a soldering gun, take a dropper, from which the tip is cut off in the area where the rubber skirt is located. Then the exposed part of the tube is inserted into the network hole of the wooden handle.
- Next, the rubberized seal (skirt) of the dropper is pressed with force against the end part of the holder, ensuring reliable sealing of the docking area.
- Upon completion of these actions, the ends of the drawn power wire are reconnected to the nichrome winding and reliably insulated.
- A piece of telescopic antenna of suitable diameter is inserted into the hole where the soldering iron tip was previously located and carefully clamped with a locking screw.
The tightness of the inlet hole in the handle will ensure effective inflation with cold air coming from the compressor station.
At the final stage of assembling the soldering gun, you should return the heating tube with the nichrome winding to its place, having previously wrapped it with several layers of aluminum foil.
Then the heater prepared in this way is recessed into a wooden handle and securely fixed using a flexible copper wire wound along the entire length of the protective coating.
Self-repair of industrial designs
Before repairing a soldering gun, first of all, you need to familiarize yourself with the connection diagram of the fan and heater to the electrical network (its other name is pinout).
Knowledge of this circuit allows you to check the correctness of the power supply to each of the main elements of the thermal module and make sure that they are in good condition.
Direct repair of a non-working soldering device comes down to replacing failed or damaged parts, which can be detected by the presence of characteristic burn marks.
When operating a soldering gun, sudden changes in operating modes (heater temperature jumps, in particular) should be avoided. In addition, it is strictly forbidden to touch the working thermal element, as well as the replaceable nozzles.
Otherwise, the operator risks serious skin burns from the hot air. Changing plastic attachments is allowed only after the soldering gun has been completely turned off and all its working parts have cooled down.
A couple of months ago I didn’t even think about a homemade soldering station. I was going to buy Lukey 702, but looking at the prices, I still didn’t understand why I would pay 6...8 thousand for it.
Lukey's disadvantages:
- The transformer power is too low, the transformer is operating at its maximum capacity.
- The quality of the transformer iron is low, it heats up even at idle, and at some stations it also hums.
- Inconvenient temperature setting (impossible to quickly set 20-40-60 degrees).
- The discreteness of setting the temperature is 1 degree, which in reality is not needed.
- A signal connector (PS/2) is installed in the power circuit.
- Constant power supply from the network, even when the soldering station is not in use.
- No auto shut off feature.
- High price.
The list is not small, so I decided not to buy Lukey. I started looking towards homemade soldering irons. The finished structures were somehow not satisfactory. Somewhere the author spared transistors for indicators. Somewhere through the diode bridge 2 amperes are pumped, and the diodes become hot like irons. Somewhere the author pumps 35 volts through the cranks. In general, it was definitely decided to invent my own bicycle.
So, I present to your attention the ZSS-01 soldering station.
Main functions:
- Convenient temperature setting.
- Simultaneous indication of current and set temperatures.
- Customizable auto-shutdown timer. After the timer is triggered, the station de-energizes itself.
- Error processing and indication. After an error occurs, the station de-energizes itself.
- Zero consumption after self-de-energization.
- Saving settings using cyclic write/read.
Soldering station diagram:
Now I’ll tell you in detail about each node of the circuit.
Display unit.
Contains two seven-segment indicators. The first indicator displays the current temperature of the soldering iron, the second - the set one. Indicators can be use with both a common anode and a common cathode, installing the appropriate firmware. The indicators are connected via a buffer chipto reduce the load on the microcontroller ports. Instead of a buffer, you can put 12 transistors, but it seems to me that the microcircuit is easier to solder,and the board layout is simplified, and it costs less than a handful of transistors. The display unit also contains a buzzer that beeps whenerrors occur, and also makes clicking noises when pressing buttons. The tweeter used is a regular one, without a built-in generator. I set the squeakerfrom an ancient motherboard. The microcontroller generates a square wave, then the square wave passes through a buffer transistor and goes to the tweeter.
Power supply unit.
A special feature of this soldering station is the ability to self-de-energize. The primary winding of the transformer is connected to the network through normally open relay contacts. When the station is switched off, the relay contacts are open and the transformer is de-energized. To start the solderingstation, you need to press the “ON” button, which briefly bypasses the relay contacts. Voltage is applied to the primary windingThe microcontroller starts up. After startup, the MK turns on the relay, bypassing the button. The transformer remains energized untilThe microcontroller will not turn off the relay. Thus, after turning off the power, the device consumption becomes zero and disappearsthe need to use a standby power source (transformers with additional windings mi, etc.).
Self-de-energizing occurs when:
- Pressing the "OFF" button on the front panel.
- The auto shutdown timer is triggered.
- No heating of the soldering iron.
- Soldering iron overheating.
The secondary winding of the transformer produces 24 volts. After rectification and filtering, the voltage rises to 34 volts. For food The microcontroller uses a pulse converter LM2596S-ADJ, which reduces the voltage to 5 volts. In case of breakdown of the built-in converter key, a suppressor removed from the hard drive board is installed at the output.
Temperature measurement unit.
To assemble the station, I bought a soldering iron from Lukey 702. The original K-type thermocouple located in the tip is used as a temperature sensor heater. To amplify the voltage from the thermocouple, a consumer-grade operational amplifier LM358 is used. The op-amp gain is selectedso that the output voltage of 5 volts corresponds to 1023 degrees, while 1 quantum of the ADC will be equal to 1 degree. UsedThe op-amp does not have a Rail-to-Rail output, so the maximum measured temperature will be approximately 800 degrees. Operating temperature rangestations from 100 to 450 degrees, so measuring up to 800 degrees suits me. After assembling the station, it is necessary to calibratetemperature using a trim resistor.
Heater control unit.
Everything is simple here. The microcontroller includes an optocoupler. The optocoupler opens the triac. A triac switches the heater to the secondary winding transformer. PWM adjustment is not used, only the heater is turned on/off, the so-called “key mode”.
Push-button control unit.
For control, 1 power and 5 signal buttons are used. In order not to spoil the appearance of the soldering station, all buttons were The same ones are used - power ones. All control comes down to turning the power on/off, setting the temperature, and setting the timerauto shutdown. By holding down the buttons, values are scrolled through quickly.
Now I’ll tell you about additional functionality.
Auto shutdown timer.
Allows you to set a time interval from 1 to 255 hours, after which the soldering station will de-energize itself. It is also possible turning off the timer. To do this, you must set the time interval to 0. To enter the timer setting mode, you mustsimultaneously hold down the “-20” and “+20” buttons, and without releasing them, turn on the station with the “ON” button. The first indicator will display the letter "A",confirming entry into the auto-shutdown setting mode, and a sound signal will sound. The "-20" and "+20" buttons must be released. On the secondThe indicator will display the number of hours that can be changed using the "-5" and "+5" buttons, and the change will occur in 1 hour increments.every press. To save the changes, you must press the "OFF" button, and the soldering station will de-energize itself.
Protection against soldering iron not heating / thermal sensor short circuit.
When turned on, the soldering station counts down 1 minute, after which constant control of the soldering iron temperature is activated. If the temperature is lower 80 degrees (for example, if the heater breaks), the error “Err 1” is displayed on the indicator, a long beep sounds, and the stationde-energizes itself. This error will also occur if the temperature sensor is short-circuited.
Protection against soldering iron overheating / temperature sensor breakage.
Overheating protection can be useful, for example, in case of breakdown of the control triac. The soldering iron heats up to 470 degrees, it works protection. The indicator displays the error "Err 2", a long beep sounds, and the soldering station de-energizes itself. AlsoThis error will occur when the temperature sensor breaks, thanks to the pull-up resistor at the input of the measuring unit.
Saving settings.
The structure with settings takes 3 bytes. The ATmega8 microcontroller contains 512 bytes of EEPROM memory. Since the memory size allows you to save 170 structures, a cyclic writing/reading algorithm for settings was implemented. The algorithm works as follows. After turning on the power,In memory, the last non-empty structure is searched and the settings are read from it. Before turning off the power, the first empty structure is looked for, and into itsettings are recorded. Thus, with each save, the settings are written to the next structure, and so on 170 times. When allthe structures will fill up and the free space will run out, the memory will be completely erased, and the settings will be written to the first structure. And so on in a circle. The use of this algorithm allows you to extend the memory resource by 170 times, and also promotes uniform wear of the cells.
Now I’ll tell you a little about the insides of the station. The transformer used is like this:
Photo of the main board during assembly.
Structurally, the soldering station consists of two boards.
The display board contains only seven-segment indicators.
One wire is not connected because... dot is not used.
All other components are on the main board.
The dimensions of the boards are adjusted to use the factory B12 plastic case, which has dimensions of 200x165x70 mm.
Entrails.
This is what happened in the end. Front view.
Back view. To connect the soldering iron, I installed some kind of Soviet connector.
Setting the auto shutdown timer.
Error indication.
Let's summarize.
Overall, I'm happy with the homemade product. You can add 20...40 degrees without straining, and not worry about leaving your soldering iron on unattended. Some components were in stock I had to buy something. List of costs:
- Soldering iron from Lukey 702 === 1013 RUR
- Toroidal transformer TTP-60 (2x12V, 2.2A) === 800 RUR
- Triac BTA25-800 === 105 RUR
- Optocoupler triac MOC3063 === 26 RUR
- Seven-segment indicator FYT-3631 === 46+46 rub.
- Tip Hakko 900M-T-3C === 500 RUR
- Double-sided tape === 75 RUR
- Delivery === 189+175 rub.
As a result, the station cost me 2975 rubles.
Future plans:
- Instead of a relay, install a triac.
- Make an automatic selection of the type of temperature sensor used (thermocouple or thermistor).
- Replace the heater with a ceramic one.
- Make the front panel matte to prevent glare.
List of radioelements
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad | |
|---|---|---|---|---|---|---|---|
| Display board | |||||||
| HG1, HG2 | Seven segment indicator | FYT-3631BD | 2 | To notepad | |||
| Basic fee | |||||||
| DA1 | DC/DC pulse converter | LM2596 | 1 | To notepad | |||
| DA2 | Operational amplifier | LM358 | 1 | To notepad | |||
| DD1 | MK AVR 8-bit | ATmega8 | 1 | To notepad | |||
| DD2 | Bus Receiver, Transmitter IC | SN74HC245 | 1 | To notepad | |||
| U1 | Optocoupler | MOC3063M | 1 | To notepad | |||
| VS1 | Triac | BTA25 | 1 | To notepad | |||
| VDS1 | Diode bridge | W04M | 1 | To notepad | |||
| VD1 | Rectifier diode | FR103 | 1 | To notepad | |||
| VD2 | Rectifier diode | 1N4007 | 1 | To notepad | |||
| VD3 | Rectifier diode | BAV99 | 1 | To notepad | |||
| ZD1 | Protection diode | SMBJ5V0CA | 1 | To notepad | |||
| VT1, VT2 | Bipolar transistor | C945 | 2 | To notepad | |||
| HA1 | Sound emitter | DBX05A | 1 | To notepad | |||
| FU1 | Fuse | 5A | 1 | To notepad | |||
| FU2 | Fuse | 1A | 1 | To notepad | |||
| K1 | Relay | JW1FH-DC12V | 1 | To notepad | |||
| L1 | Inductor | 120 µH | 1 | To notepad | |||
| L2 | Inductor | Ferrite bead 0805 | 1 | To notepad | |||
| R1 | Resistor | 680 Ohm | 1 | 2 Watt | To notepad | ||
| R2 | Resistor | 3.01 kOhm | 1 | 1% | To notepad | ||
| R3 | Resistor | 1 kOhm | 1 | 1% | To notepad | ||
| R4 | Resistor | Jumper 1206 | 1 | To notepad | |||
| R5, R6 | Resistor | 360 Ohm | 2 | To notepad | |||
| R7, R18, R19, R21, R22, R24, R25, R26, R27, R28 | Resistor | 330 Ohm | 10 | To notepad | |||
| R8, R20 | Resistor | 100 kOhm | 2 | To notepad | |||
| R10, R11, R12, R13, R14, R15 | Resistor | 10 kOhm | 6 | ||||
I’ve been dreaming about a soldering station for a long time, I wanted to go out and buy it, but somehow I couldn’t afford it. And I decided to do it myself. I bought a hair dryer from Luckey-702, and began to slowly assemble 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). Approximate pinout of hair dryer wires Luckey 702 in the photo below, but I recommend taking your hair dryer apart and seeing what goes where, you understand - 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 function for cooling 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. Sincerely, AVG.
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