In some areas of the apartment (kitchen, hall) door, usually left open. And fix it in this position will help ordinary magnet, mounted on the wall, but if the handle is steel. The magnet can be embedded or simply stick to the wall, opposite the door handles. A. LATYSHEV, G. Almalyk
Recommend to read
TEMPORARY! ON WEDGES
Not always rack shelves require a stationary position. Temporarily any of them can be attached using derevyannyh wedges placed in the gap between the flange and the wall of the Cabinet.
THE LIGHT WILL ACTIVATE THE SIREN
The proposed German magazine "Funkamateur" light relay is activated when light falls on the photoresistor R1 (see diagram) — when this occurs, a loud siren sound. Transistors VT1, VT2...
