Can we attach a sensor
 

Ron, We are totally new at this, but of course we are trying to reinvent everything. Question: Can we attach a sensor to one of the 2 liter bottle that will turn pump on, thus no timer and a better way of watering?? I know it probably been done and failed. Thanks, Al

I thought about the sensor idea. I even bought a rain gauge for lawn watering system to see if could covert it to my use. I wanted to find a way to shut off the pump when the water reaches a certain height in the bottles. That part is easy but when the pump shuts off and the water lowers below the sensor it would come on again to soon. You would still need some way to reset it to come on again every 30 minutes or so.