Richard Hirschmann Radiotechnisches Werk

Klaus Hirrlinger

Hans-Dietrich Mayer

Hans-Dieter Mayer

Monitoring a room is accomplished by measurement of air pressure where air passage resistance between a secured room and an outside atmosphere is measured and an alarm actuated, if the air passage resistance drops below a predetermined value. Evaluation of typical air pressure fluctuations in a frequency range between 0.01 Hz and 10 Hz is advantageous. The air pressure resistance may be determined by difference measurements of air pressure fluctuations in the outside atmosphere and the secured room, or as a singular process wherein a connecting tube is provided between the room to be secured and the outside atmosphere, where air movements varying as a function of air pressure fluctuations are measured. Devices for the carrying out of the process are described. The devices and the process provide a simple and cost effective alarm system that operates reliably and is secure against outwitting and sabotage.

Security alarm process and apparatus

A circuit layout for continuous display of power consumption of an electric device includes a light emitting diode actuated by voltage pulses, the frequency whereof corresponds to the current draw of the electric device. It is possible to determine directly whether the instantaneous power consumption of the electric device, in particular a household device, is low or high in case of varying loads as the frequency of the voltage pulses and thus the flashing frequency are below the flicker limit resolvable by the human eye. The power consumption display can be manufactured in a highly cost effective manner and in a compact configuration, so that it may be placed in an electric outlet housing.

Growing community of inventors

Esslingen, Germany

Klaus Hirrlinger