One wanting to log periodic data on his embedded system with a standard and robust method might be interested by the following instructions.
From wikipedia: "RRDtool (round-robin database tool) aims to handle time series data. The data are stored in a circular buffer based database, thus the system storage footprint remains constant over time. It also includes tools to extract round-robin data in a graphical format, for which it was originally intended. Bindings exist for several programming languages."
$ make menuconfig
... Target packages ---> ... Graphic libraries and applications (graphic/text) ---> ... [*] rrdtool
- then reflash your rootfs
- Check your system has the correct date/time:
- If not, then set it ;-)
- Create the database:
# rrdtool create /data/battery.rrd --step 120 DS:cap:GAUGE:240:0:100 RRA:AVERAGE:0.5:1:1200
- Feed the script with data (XX):
rrdtool update /data/battery.rrd -- N: