Custom Dobiss master hardware

This solution to replace the master of this Dobiss lighting switch bus consists of:

• A Raspberry Pi 5 4GB

• A Raspberry Pi Pico

• A logic level shifter (Adafruit 4-channel I2C-safe Bi-directional Logic Level Converter - BSS138)

• A 1k Ohm resistor

• A SH-C30A DSD TECH USB to CAN Bus Adapter

  The Pi 5 acts as powersupply and processes the messages which are sent on the bus.

  The Pi Pico handles the low level communication. It generates the reset pulse and requests the unique ID if a presence pulse is detected. THe unique ID is communicated to the Pi 5 by using serial over USB.

  The low side of the logic level shifter is connected the 3.3 V pin (pin 1) and a ground pin (pin 9) of the Pi 5. One of its low side pins (A4) is connected to a GPIO pin (pin 20) of the Pi Pico.

  The high side of the logic level shifter is connected to the 5V pin (pin 2) and a ground pin of the Pi 5. Finally a high side pin (B4) is connected to the data wire of the bus (D).

  The bus itself (the D wire) is connected to the 5V pin with a 1K Ohm pullup resistor.