The stand-alone USB Weather Logger published in the September 2011 issue of Elektor records accurate atmospheric pressure, temperature and humidity readings from I²C-bus sensors and displays readings on a built-in LCD module. It can run for six to eight weeks on three AA batteries. Digital sensor modules keep the hardware simple, and no calibration is required.
Stored data can be read out over USB and plotted on a PC using gnuplot. The unit is able to record data at up to six records per hour, with each record containing a set of pressure, temperature and humidity readings. The data storage capacity in nonvolatile memory is 8191 records.
A complete parts kit is available from the online Elektor Shop. The bare PCB, sensor modules and preprogrammed ATMega microcontroller for the Weather Logger are also available separately.