Earlier this year Arhi developed a soldering iron driver (machine translation) that works with both PTC and K-type TC temperature sensors. In this design a microcontroller implements PID temperature control of the soldering iron, and shows the relevant information on a display. His posts in the forum inspired us to build one too.
The soldering iron type is selected by jumpers. The actual temperature is read by amplifying the sensor signal with an op-amp, and feeding it to the analog to digital converter input of the uC.
Our version of his driver adds a few things to Arhi’s design. It has both a UART and USB interface that can control and monitor the soldering iron, and update the firmware. We added a button and an extra LED. The button switches the heater on and off while the driver is still on.
Our board uses a single layer and all through hole components, so it can be etched at home. The minimum trace width was set to 16mil, and the spacing to 14mil, to make it as simple as possible for people to make DIY boards.
The amplifier output, 5v power supply, ON/OFF button, and the triac jumper are broken out to allow for easier prototyping and further development.
While the current version uses the 24VAC input from a soldering station transformer, one future goal is to make our board laptop power supply friendly.
A special thanks to Arhi for releasing his open source soldering iron driver, and his help with our design.
Very nicely done!
I got so used to SMD components, that my first thought is – the board is so big :P I will be grateful for smaller version.
Laptop PSU support would be really great!
I think the highest voltage commonly seen is 19VDC. That might mean that heat up and recovery would be a bit slower than 24VAC, but the possible saving in weight and being much easier to source would make up for it.
Good job Arhi and DP team. It’s about time there was an open hardware soldering iron driver.