How to use a toy laser gun to remotely control a light switch

The toy laser gun is small in size, the size of a human thumb, and can be carried around. The laser emitted by this laser gun is highly directional, well focused, and does not spread. The laser point can be seen hundreds or even thousands of meters away. This laser gun is not only used as a toy for children. With a little development, its practical value can be discovered. For this reason, this article uses the toy laser gun to make a laser remote control light switch. This laser remote control light switch can remotely control lights at a long distance, providing convenience for people to turn on lights.

The circuit is shown in the figure above. The left side of the dotted line is the remote control light switch circuit. The 220V AC power supply is rectified by D1-D4 bridge, stepped down by R1, filtered by C2, and stabilized by DW to obtain 9V DC power to supply the working voltage of the control circuit. ICA and ICB are dual master-slave D-type flip-flops CD4013. I-CA and ICB are one of the D-type flip-flops. Each D-type flip-flop has an independent data input terminal D, set terminal S, reset terminal R, clock input terminal CP, and output terminals Q and Q. The role of C3 and R3 is to generate a momentary high level at the R2 terminal of ICB when the power is just turned on, so that ICB is reset, Q2 is low, the unidirectional thyristor VS is cut off, and the light bulb H is extinguished. ICA and peripheral components form a monostable trigger circuit, and ICB and peripheral components form a bistable trigger circuit.

To turn on the light, use a toy laser gun to shine on the phototransistor V, the resistance of V decreases, so that the set terminal S1 of ICA gets a high level pulse, Q1 becomes high level, this high level is added to the CP2 terminal of ICB, ICB triggers flipping, Q2 outputs high level, VS control electrode gets the trigger voltage and turns on, and the bulb H lights up. The role of R4 and C4 is that when Q1 outputs high level, after about 0.5 seconds, ICA resets, Q1 becomes low level again, so as to prepare for the next work. If you want to turn off the light, just use the toy laser gun to shine on V again, at this time Q1 outputs a high level again, ICB flips again, Q2 becomes low level, VS is cut off, and the bulb H goes out.

V uses 3DU phototransistor, VS uses MCR100-8 unidirectional thyristor, H uses 40W, 220V incandescent bulb, and other component data and models are shown in the figure above.

When making it, you can modify the commonly used 86-type switch board and make a printed circuit board. Solder the components of the remote control switch on the circuit board (see the figure below), fix the circuit board on the back of the 86-type switch board, and seal the circuit board with a small plastic box. Then make a small hole on the front of the 86-type switch board, install the V at the small hole, and use a long cylindrical filter glass to increase the anti-interference ability to prevent other light from triggering by mistake. Finally, connect the incoming and outgoing lines of the light power supply to the remote control switch board.