Switching high currents and voltages from an Arduino requires additional components to work around the low voltage and current levels an Arduino can handle. This shield provides four MOSFET driven outputs that are isolated from the Arduino digital pins, two isolated digital inputs, and appropriate power input connections. The isolation ensures that no high voltages or currents can be sunk into your Arduino.

This project was a collaboration with Haldey Rich at nicegear.co.nz.

Current Build

The latest design is version 1.1. It has not yet been tested. Version 1.1 has known problems with where the optoisolator sources power from, expect a 1.2 revision soon.

Changes made in 1.1:

  • Space for an 78XX pin-out LDO, or drop-in replacement of a similar function, along with input and output smoothing capacitors
  • Bypass jumper for the LDO, VIN terminals then act the same as 1.0
  • Wider traces on the high power side, to support higher currents
  • 5.0mm pitch terminals on the high current side

The 1.0 revision has been assembled and tested. Like 1.1, it has problems with where the optoisolator sources power from.


Schematics and PCB layout

The schematics for 1.1 are below:

The schematics for 1.0 are below:


Schematics and PCB design are released under the Creative Commons BY-SA license.