“Candle” — light bulb with a power of 50-60 watts. “Pistol” — a tube-tube in which is placed the photodiode, and the handle with the trigger button. The photodiode and the lamp are connected through the electronic circuit.
Task arrow to bring the gun on the burning lamp and press the button KN1. Triggered time relay transistor T4 and the contacts R2/1 connect the output of the amplifier, assembled on transistors T1, T2, to the input of the AC relays (T3). When the light from the lamp falls on the photodiode, the collector of T2 there is an alternating voltage of 100 Hz frequency (the lamp is fed with alternating current). Relay R1 and its contact R1/1 closes the feed circuit of the relay R3. The contacts R3/2 immediately turn off the lamp “candle” is extinguished.
Scheme reset button Кн2: the relay R3, and the lamp-the candle lights up again.
The design of the pistol may be any. It is important that diode was lit for accurate aiming. The lamp power determines the limit distance shooting. For example, the lamp power of 100 W can “hit” from a distance of 15-20 m.
A few words about the details. As T1—T4 can use any low power low frequency transistors: МП39—МП42, MP20, P13—R16. Diodes D1—D4 D226, D7; D5, D6 — point D2, D9 with any alphabetic indexes. P1—P3 — relay РЭС6 RES9, РЭС10 or the other with a trigger voltage of 9 to 15 V. the Transformer TR1 is step-down. Its secondary winding is designed for a voltage of 12 V.
An electronic circuit is mounted in a small housing, on which is mounted a lamp receptacle.
It is best to use the light bulb Mignon: its easier to “make up” of a candle.
“Candle” can be placed on the tree. Then the box with the electronics installed in inconspicuous place. The gun is connected to the circuit with shielded wire, making sure no interference from the network.
R. SALAVATOV, Novosibirsk, Russia