The 8HP is the new auto transmission to swap, providing almost DCT-like shifting while retaining daily-driver refinement. See 8hp.info for a good overview of 8HP transmissions. The goal of this project is to lower the barrier of entry to 8HP swaps by providing a cheap, open-source alternative to fantastic, but ridiculously expensive 8HP TCUs such as Turbolamik or CanTCU.

The architecture of the TCU isn’t too complex, but as a MechE I’m learning a lot about embedded systems and PCB design as I lock down my scope and learn more technicals. The hardware roughly consists of:

  • Logic stage: STM32F4 MCU
  • Power stage: gate drivers, low-side MOSFETs, flyback diodes
  • Communication: MCP2515 CAN transiever
  • Analog input stage w/ RC filters
  • 12V-tolerant digital inputs & outputs

While I have rough KiCAD schematics for the hardware, I’m currently focused on learning the STM32 HAL and C++ since that’s what I know the least. So far, I’ve successfully made an LED turn on/off with a button (woo-hoo!). Next step is to control LED dimness with a potentiometer to learn PWM/timers and reading analog inputs.