A soldering station is probably one of the first things a maker should invest in. The ability to build your own equipment is what quilifies you as a maker. Building my own soldering iron controller was in my To-Do list for months. I found a cheap chinese clone of the Hakko 907 iron and discovered that there are a lot of diy controllers for this iron out there.
I used an Arduino pro mini compatible board to keep it simple and open source so other makers could build it and improve it. I discovered Kuro’s soldering station and decided to build my controller based on his with a few additions. I used his firmware to control the temperature with PID. Also I use an RGB LED and a bar graph on the screen to visualize the tip temperature. The extra buttons on my board are used to control the screen brightness and enable/disable rounded temperature. The brightness value and the P, I, D parameters are stored in the EEPROM.
I have made a few changes in the firmware. Some of them require changes or additions on the PCB and inside the iron’s handle.
– I added a buzzer that beeps on every button press and when the station enters sleep mode or turns off. I soldered it directly on pin 13 of the arduino pro mini.
– A lot of people were asking for sleep mode. I added a function that turns off the heater after a predefined time period but that wasn’t enough. I soldered a reed swith inside the iron’s handle. It’s connected between Analog 4 (Digital 18) and ground pins of the pro mini. I added a magnet on my base. When I leave the iron on the base, the reed switch closes and it enters sleep mode after 30″ (target temperature: 150°C). After 5′ in sleep mode the heater turns off.
-For safety reasons the heater turns off if something goes wrong and the temp exceeds the MAX temp + 30°C for more than 5″.
-I added a new progress bar on the screen and a new temp icon. Also the duty cycle is shown on the screen.
-As you can see on the video below there is a boot screen that goes away when I put the iron on the base. That way I always remember to put it on the base before turning it on for the first time and prevent entering sleep mode before reaching the target temperature.
I still have to calibrate it by measuring the actual temperature of the tip with an external device but that would be as easy as changing two parameters.
If you need the PCB files send an empty email at solderingfiles [at] hackermagnet [dot] com. (The email address is not monitored. You will get a respond with download links for all the necessary files.)