In this post I will present the finished firmware, its features, and two small hardware changes I made.
I made two controllers, one for the JBC tips and one for the Hakko T12. The original controller used a sort of sensor on the handler which woke up the station when shaken. This would not work with the JBC tips due to the lack of space on the handler for the sensor, and also even with the T12 handle the system requires a vigorous shake to make it work.
I decided to make a small change on the hardware so that the wake function works similar to the original JBC stations. The iron stand is weakly pulled up and goes to ground when the handle is resting on it. This signal is fed into the controller which then handles the wake functionality accordingly.
For this to work the tip ground must be connected to the the tip chassis. Although this rarely presents a problem I used a switch on the back of the case to undo this connection if needed.
One other small change I made was to place the ntc temperature sensor used for cold junction compensation inside the T12 handle, ideally it should be placed as closed to the tip termocouple as possible.
On the JBC handle this mod is impossible due to the small size of the handle.
Connections to the tips
IMPORTANT – According to Stefan Trethan this connections are wrong for JBC T245 tips. I use T210 and just assumed they were all the same, but it appears they aren’t. Please refer to this for a workaround.
Custom firmware features
- PID for temperature control
- Cold junction compensation
- Memory for 10 different tips
- Per tip PID constants
- Per tip termoucople calibration
- Boost mode (used when one requires a temporary boost in temperature, triggered by the press of a button, resumes normal temperature after an amount of time defined by user)
- User defined boost time and temperature
- User defined sleep time and temperature
- User defined stand by time
- Set temperature saved between uses
- 3 point calibration values
Made a quick video showing the firmware, it was made with the JBC tip
Source is available from GitHub
Compiled ELFs available here