Markets is often found in children's toy - "cell phone". With one of its buttons, in my instance is "1", has an interesting logic. While on the button is not pressed three times, the ringtone will not play. This option allows to turn the toy on the combination lock call.
The essence of the alteration is clear from the figure: you need to solder to the printed conductors coming to the button "1", the two wires in the insulation and connect them with door bell button (SB1). To use such a device need to warn my friends and acquaintances about "code" call. Then the first two presses of the button to nothing lead, and after third in the apartment you will hear a melodic sound. Only the third time the button should be pressed no later than two seconds after the second press. Otherwise the whole procedure you will have to repeat.
Author: Vladimir Smirnov