Detect voltage-problems

[markbaaijens]

A Pi can be under-powered to the point it is bearly useable. Many of the problems origins from an under-powered power-suppy. We must detect this situation and warn a user in the RPMS-interface.

Code to determine if there are power-problems: dmesg | grep -i undervoltage

Under Home, under Uptime:

• Power Quality
  • green checkmark if OK
  • red cross if not OK

Implement as a stand-alone API-function GetPowerQuality => boolean

Background

• https://pimylifeup.com/raspberry-pi-low-voltage-warning/
  • vcgencmd get_throttled
  • gives '0x0' when everything is ok
  • => dmesg | grep -i undervoltage
• https://forum.libreelec.tv/thread/17860-how-to-interpret-rpi-vcgencmd-get-throttled/
  • decoding vcgencmd get_throttled
• https://blog.mccormack.tech/shell/2019/01/05/monitoring-raspberry-pi-power-and-thermal-issues.html
  • some python code

Research

• test power supplies, including the 'offical' ones; when and where does under-voltage appear?
  • only the official one has no power problems
  • all other 'normal' adapters have problems, also the ones who are capable for 'turbo-charging'

[mimefly]

Pi4b 4gb, booting from sd card (RPMS), 2 usbsticks, and a wireless dongle (keyboard)

• Official power supply + cable: works (dmesg | grep -i undervoltage -> no result)
• OnePlus 3T power supply (turbo charging) + cable: appears to work (dmesg | grep -i undervoltage -> no result)
• official Samsung S10+ power supply + cable: appears to work (dmesg | grep -i undervoltage -> no result)

[mimefly]

Pi4b 4gb, booting from sd card (RPMS), 2 usbsticks, and a wireless dongle (keyboard)

• Official power supply + cable: works (dmesg | grep -i undervoltage -> no result)
• OnePlus 3T power supply (turbo charging) + cable: appears to work (dmesg | grep -i undervoltage -> no result)
• official Samsung S10+ power supply + cable: appears to work (dmesg | grep -i undervoltage -> no result)

Some off brand power supplies do not work (e.g. Action)

[markbaaijens]

Nice.. So by now you can start writing the code for this issue while having the opportunity to test the code yourself.