My challenge to solve:
- 6 solenoid valves working at 9V which I need to switch on and off based a schedule.
- 4 wires to reach the valves
- Use an old Core or an Argon which cannot be placed near the valves
- Somehow need to extend the digital outputs only using the 4 wires
- The 4 wires should carry also the 9V power for the solenoid valves to run
My initial idea was to extend the output of the Core via I2C with an MCP23017 (4 wires): 9V and GND
with a step-down to 3.3V and than the SCL and SDA.
Maybe using a step-down like this
Would this work, or is conceptually wrong?
How long max can the 4 wires be teoretically: 5m, 10m, 20m?