Monday, June 27, 2011

NotesToMyself: OpenBSD sensorsd Based Battery Monitor

Setting up a plain and simple battery monitor using OpenBSD's sensorsd framework.

Get a list of sensors:

dennis@ipa:~$ sysctl hw.sensors
...
hw.sensors.acpibat0.watthour0=4.35 Wh (last full capacity)
hw.sensors.acpibat0.watthour1=0.43 Wh (warning capacity)
hw.sensors.acpibat0.watthour2=0.00 Wh (low capacity)
hw.sensors.acpibat0.watthour3=3.24 Wh (remaining capacity), OK
hw.sensors.acpibat0.raw0=1 (battery discharging), OK
hw.sensors.acpibat0.raw1=1957 (rate)
...

Configure /etc/sensorsd.conf similar to:

# alert if remaining capacity < warning capacity
hw.sensors.acpibat0.watthour3:low=0.43Wh:command=/usr/X11R6/bin/xmessage "battery is low"

Start/restart sensorsd via sudo /usr/sbin/sensorsd or sudo pkill -HUP sensorsd

Set sensorsd_flags="" in /etc/rc.conf.local to stick around on boot.

If remaining capacity goes below the warning capacity, a xmessage pop-up will interrupt you.