Caution

This is the documentation for the current development branch of the CometVisu. It is possible that some of the described features are not yet available in the current release.

Also there might be lots of errors in this documentation as some parts of the content have been translated by an online translation service.

CPU Temperature for Raspberry Pi

The current CPU temperature of the Raspberry Pi can be filled with this script in an RRD database. This script works like this if it is stored (and executable) under /var/www/rrd/cputemp

#!/bin/bash
#
# update .rrd database with CPU temperature
#
# $Id: update_cputemp 275 2013-05-16 05:20:56Z lenik $

cd /var/www/rrd

# create database if not exists
[ -f cputemp.rrd ] || {
/usr/bin/rrdtool create cputemp.rrd --step 300 \
DS:cputemp:GAUGE:1200:U:U \
RRA:AVERAGE:0.5:1:3200 \
RRA:AVERAGE:0.5:6:3200 \
RRA:AVERAGE:0.5:36:3200 \
RRA:AVERAGE:0.5:144:3200 \
RRA:AVERAGE:0.5:1008:3200 \
RRA:AVERAGE:0.5:4320:3200 \
RRA:AVERAGE:0.5:52560:3200 \
RRA:AVERAGE:0.5:525600:3200
}

# read the temperature and convert 59234 into 59.234 (degrees celsius)
TEMPERATURE=`cat /sys/class/thermal/thermal_zone0/temp`
TEMPERATURE=`echo -n ${TEMPERATURE:0:2}; echo -n .; echo -n ${TEMPERATURE:2}`

/usr/bin/rrdtool update cputemp.rrd `date +%s`:$TEMPERATURE

The following line must be added in /etc/crontab to call the script every 5 minutes:

*/5 *   * * *   root    /var/www/rrd/cputemp