Schematic, PCB files, firmware and 3d models for creating the IoT12 solder iron temperature controller for T12 compatible tips.
IoT12
IoT12 is a portmanteau: IoT because the controller talks WiFi, T12 for the tip. It is a soldering iron controller you build from three PCBs, firmware and a 3D-printed case. I made it because the closed commercial stations annoyed me - every layer here is open and hackable, and the ESP32 exposes the iron over the network.
The build
- Three PCBs. Control Board, Power Supply, Display Adapter.
- KiCad schematics, ATOOMNETKICAD library.
- Firmware for ESP32 and SAMD21.
- 3D-printed case, FreeCAD source and STLs.
How the iron stays hot
The T12 tip is the heater and the thermocouple at once. The Control Board pulses +24 V through it, then reads the tiny voltage the tip produces when the power is off - that is the temperature. A SAMD21 runs that loop. The NTC on the handle gives a second temperature, the tilt sensor detects shake-to-wake. The ESP32 does the WiFi, the display and the speaker. Power comes from a dedicated supply board delivering +24 V and +5 V.