... for temperature sensors.
* Soil Moisure Sensors are responsible for sensing if the soil of irrigated flowers are wet or not. These sensors are attached to the Sensor Controller Module via slow speed I2C bus. The modules use 2-pin probes and drives them with 4 kHz square wave in order to avoid oxidating the probes.
In my implementation I used these small water pumps from Conrad: http://www.conrad.hu/conrad.php?name=Products&pid=539090
The whole system is powered by a 12V / 4A SMPS.