Heat Waves Set Off New Thief Alarm (Apr, 1932)
Heat Waves Set Off New Thief Alarm
THE heat from a burglar’s body, even the gentle warmth of his breath, may now be detected by science’s latest contribution to crime prevention, the “heat radio.”
The heart of the “heat radio” is a very tiny and very delicate thermocouple, which is mounted at the focal point of a large metallic reflector. This reflector, shown in the accompanying illustration, collects the feeble heat waves and concentrates them on the super-sensitive thermocouple.
An amplifier connected to the thermocouple amplifies the current generated about one million times, making it strong enough to operate a recording instrument at police headquarters or an alarm bell.