On/Off Shim + DigiAMP+


I wondered if the power on/off shim (OnOff SHIM (micro-USB)) would work with the DigiAMP+?

It has an external power supply which powers the pi.

I’m looking for a way to switch off the “hi fi” mechanically.

Cheers all!

You can have the Pi do a shut down via a button press. And boot back up via a button press. It doesn’t remove the +5V though. Do you also need to remove power?

I can leave power +5v I think. Does it work though that the USB on the shim replaces the Pi’s USB power? As with the DigiAMP+ plugged in, it supplies the power to the pi (you can’t have power from the Pi plus the power-pack for the DigiAMP+ at the same time).

The on off shim relies on the power coming in its power jack. The way it works is, it sends a signal to the Pi to shut down the OS. Once thats done, a signal is sent back to the shim to cut the power. To turn the Pi back on it toggles the power back on. The Pi is being powered via the +5V pin on the GPIO header.

If all you want is a shutdown function, all you need is a button wired up to ground GPIO 3 when pressed. And a dtoverlay entry in your config.txt.
If you shut down, and leave the Pi powered, momentarily grounding GPIO 3 will have it boot up again.
You can also set it up to use a different GPIO pin.
On my Fan Shim I use this.

Thanks, I was aware of the GPIO3 but because the DigiAMP+ also uses the pin, I assumed I couldn’t use it?

It depends on whether i2c is enabled or not. The on function works regardless. But if i2c is enabled, you can’t use GPIO 3 for shutdown. You have to specify another pin, gpio_pin=