Reduce energy consumption

[redfast00]

See for example https://blues.com/blog/tips-tricks-optimizing-raspberry-pi-power/

We have a USB power meter in the kelder

[redfast00]

On the Pi, there are possible power savings; but there might also be possible power savings on the switch: it might not need the full 9 volts (possibly the main circuitry is behind a linear regulator). We should measure the current consumption, and if it is high enough, look at the circuit and see if voltage reduction would be possible

[redfast00]

Francis had an interesting idea: eliminate the switch altogether, replace it with a USB ethernet dongle. Some tradeoffs worth considering:

• maybe less energy consumption, maybe more (since we then have to power the USB hub in the pi instead of being able to turn it off; but we get to eliminate the switch)
• more complexity: we will need to configure the dongle to be bridged to the built in port of the pi; this needs to be done in software instead of in hardware. More chance that something goes wrong, I guess.
• more flexibility (but not sure what we can do with it)
• the dongles will need to be bought; this money could also be invested in better/bigger batteries?