Electronic – arduino – Low power method to turn Raspberry Pi on or off using an Arduino

arduinoopto-isolatorraspberry pirelay

I want to use an Arduino to control power to a Raspberry Pi.

The power supply to this system is a solar panel with rechargeable cells, and the Arduino will turn the Pi off to preserve power in darkness or when the cells are running low.

So, I'd like to be able to switch the power as efficiently as possible.

What are my options? How much power might I lose with a suitable relay? I thought an optocoupler might be one way, but can I use one to switch around 500mA?

Best Answer

A small 5V latching relay will do it. As it latches, it consumes no power except when changing state.