Smoke Detector

In the late 1930s, Swiss physicist Walter Jaeger tried to invent a sensor for poison gas. He expected that gas entering the sensor would bind to ionized air molecules and thereby alter an electric current in a circuit in the instrument. His device failed: small concentrations of gas had no effect on the sensor's conductivity. Frustrated, Jaeger lit a cigarette and was soon surprised to notice that a meter on the instrument had registered a drop in current. Smoke particles from his cigarette had apparently done what poison gas could not. Jaeger's experiment was one of the advances that paved the way for the modern smoke detector. The first truly affordable home smoke detector was invented by Duane D. Pearsall and Stanley Bennett Peterson in 1965, featuring an individual battery powered unit that could be easily installed and replaced.[6] These first units, dubbed "SmokeGuard 700," were made from strong fire resistant steel and shaped much like bee hives. The idea for mass production came from Peterson, working at Pearsall’s company, Statitrol Corporation, in Lakewood, Colorado in 1975.