Abstract: A sensor control device for controlling the operation of a device such as an air blower, including a sensor capable of sensing a change in the environment from a predetermined level and providing a signal corresponding to the change and a logic means capable of receiving the signal and based upon this signal control the operation of the blower device in such a manner that its operation is in proportion to the change in the environment while inhibiting small changes from affecting the operation of the blower. The sensor device is particularly advantageous in controlling the amount of circulation provided by a blower device interposed between a thermal collector and a building so as to provide the circulation of thermal energy therebetween.