Jeff Geerling measured 1.8W idle power draw.
Based on my experience with previous Pis, I bet you’ll be able to drop that even further by turning off unused board components at boot time.
Based on my experience with previous Pis, I bet you’ll be able to drop that even further by turning off unused board components at boot time.
The same likely can be built on top of an RPi, using, say, wake-on-LAN signaling, or some GPIO as an interrupt source. You'll have to suspend your OS while idle for a prolonged time though.
# Disable Power LED after boot
dtparam=pwr_led_activelow=off
# Disable SD card activity led
dtparam=act_led_trigger=none
dtparam=act_led_activelow=off
# Disable the ethernet LEDs - these are Pi4 specific values.
# Look in the docs for the values for other Pi boards.
dtparam=eth_led0=4
dtparam=eth_led1=4
It appears to depend on firmware or kernel but for recent kernels (recent 6.1 or 6.2) activelow is no longer necessary [1]. It seems to work on CM4.
PS: my bad I disabled the LEDs via /sys not /proc previously:
> # for i in /sys/class/leds/*; do echo 0 > "$i/brightness"; done
The required lines were different between the Pi 2 and Pi 4 I was using at the time, and the documentation was not updated (or I'd found old docs).
An exercise in trial and error.