Electronic touch switch for operating an electrical circuit uses low-tension detector with one branch in contact with sensitive article such as a plant

摘要

Touch switch incorporates a low-tension detector based on an unstable multivibrator and contains a miniature electronic card (14) with printed circuit and a spring (15) ensuring contact with a metal tip (16). The detector is connected by a sheathed and earthed cable (13) to a power controller (18) containing a micro-controller that measures variations in oscillation frequency, and a power relay. The touch switch incorporates a low-tension detector based on an unstable multivibrator and containing a miniature electronic card (14) with a printed circuit and a spring (15) ensuring contact with a metal tip (16). The detector can be set in the soil in a plant pot or in water in a vase of cut flowers, and is connected by a sheathed and earthed cable (13) to a power controller (18) containing a micro-controller that measures variations in oscillation frequency over a fixed period, and a power relay. The power controller is connected to a socket (20) into which a lamp can be plugged, enabling it to be switched on by lightly touching the plant or flower.