Abstract: An apparatus for automatically controlling a watering system in response to a comparison of an ambient condition with a time-varying reference level having an adjustable maximum value is disclosed. The invention includes an electrical circuit for monitoring and sensing the magnitude of the ambient condition and for converting the sensed magnitude into a proportional electrical signal. The invention further includes a first timer circuit for generating a triggering signal when the time-varying reference level exceeds the magnitude of the proportional electrical signal. This triggering signal is applied to a second timer circuit which actuates the watering system for a predetermined period of time in response to the triggering signal.

Abstract: Apparatus for automatic control of environmental conditions in building interiors, particularly in greenhouses where exacting conditions of temperature must be met. The apparatus consists of electronic circuitry for sensing and providing output indication of temperature, incident solar radiation, daily solar radiation accumulation and nocturnal temperature modification, an executive set-point and an insecticide control set-point, all of which outputs are applied to a summation device whereupon level detection actuates control circuitry to activate heating and/or cooling apparatus, insecticide control apparatus and other attendant equipment.