#flybackdiode

We're testing out an I2C-to-solenoid driver today. It uses an MCP23017 expander. We like this particular chip for this usage because it has push-pull outputs, making it ideal for driving our N-channel FETs and flyback diodes. The A port connects to the 8 drivers, while the B port remains available for other GPIO purposes. For this demo, whenever we 'touch' a pin on port B to ground, the corresponding solenoid triggers provide an easy way to check speed and power usage.

Terminal blocks allow for quick wiring to power and each high current output, including one chunky block for the power input. The other 8 expander I/Os are exposed if you want buttons or simple LEDs. The breakouts have stemma QT for fast chaining/control over I2C.