Parts and Designs
Letting a processor control sprinkler circuits is simple, requiring only a way to control a relay, so we started our design at the sensor end of the system.We failed to find an affordable, lowmaintenance soil moisture sensor for over a year, and were on the verge of starting to modify one of the cheap soil moisture meter probes to create a PC interface. Fortunately, we found both an inexpensive sensor and a sensor subsystem incorporating that sensor.