Hello again,in this section we will make a professional soldering station
Original idea was from here
the circuit is based on atmega8 from Atmel
The main idea is to observe the temperature of the soldering iron through a k type thermocouple and in proportion ,control the supply to the soldering iron.It is based on the p.i.d controller for a better and more accurate results.The circuit is power from 9-15 volts. Thermocouple is connected to MAX 6675. All compontes are very easy to find.
On each Cycle:
Error = SetPoint – Tip
Total_Error = Total_Error + Error
P = Kp * Error Or P = Kp * Error * Tip
I = Ki * Total_Error
D = Kd * ( Error – Previous_Error )
PID_out = P + I + D
PID_out is limited in range of -500 to +500
PID_out = PID_out + 500
And now we power the soldering Iron for PID_out milliseconds
Previous_Error = Error
Part list
R1 Resistor 470 Ohm 1/4 Watt 5% Carbon Film
R2 Resistor 470 Ohm 1/4 Watt 5% Carbon Film [
R3 Resistor 1 KOhm 1/4 Watt 5% Carbon Film
R4 Resistor 1 KOhm 1/4 Watt 5% Carbon Film
R5 Potentiometer 1 KOhm Linear Rotary 1/2W
R6 Potentiometer 1 KOhm Linear Rotary 1/2W
R7 Potentiometer 1 KOhm Linear Rotary 1/2W
R8 Potentiometer 1 KOhm Linear Rotary 1/2W
R9 Potentiometer 1 KOhm Linear Rotary 1/2W
R10 Potentiometer 1 KOhm Linear Rotary 1/2W
C1 Electrolytic Capacitor 470 uF 25 Volts
C4 Electrolytic Capacitor 220 uF 25 Volts
C3 Ceramic Capacitor 0.1 uF 50 Volts
C5 Ceramic Capacitor 0.1 uF 50 Volts
C2 Ceramic Capacitor 0.1 uF 50 Volts
C6 Ceramic Capacitor 0.1 uF 50 Volts
D1 1N4004
T1 2N3904 NPN
IC1 7805
IC2 ATmega8 Microcontroller
IC3 MAX 6675 Cold-junction compensated K-Thermocouple to digital converter (0°C to +1024°C) [Cold-junction compensated K-Thermocouple to digital converter (0°C to +1024°C)]
LCD 16×2 Character LCD w/ HD44780U1 controller
R1 Resistor 470 Ohm 1/4 Watt 5% Carbon Film
R2 Resistor 470 Ohm 1/4 Watt 5% Carbon Film
pot. 4.7k
T1 2N3904 NPN
IC1 MOC3021 Random Phase Optoisolator TRIAC Driver Output [Random Phase Optoisolator TRIAC Driver Output ]
Lfuse = E4h
Hfuse = D9h
Pontesiometer R5 varies the Kd factor from 0.00 to 100.00
Pontesiometer R6 varies the Ki factor from 0.00 to 100.00
Pontesiometer R7 varies the Kp factor from 0.00 to 100.00
Pontesiometer R8 varies the max temperature from 0 degrees C to 512 degrees C
Pontesiometer R9 varies the safe time from 0sec to 900sec
Hex file here:
Homemade_Soldering_Station_2_AVR_4
here is the pcd
start soldering the smd IC to the bottom side
and after that all the other components
here is the small pcb with the optocoupler and the triac
Lets continue with the soldering iron. It is a cheap soldering from ebay for around 5 bucks.I tried to place the thermocouple as closer as i could to the tip ,so that the measured temperature to be as accurate as it could be.
Next, is the wooden box