Circuit sharing: sound and light control power switch circuit design

The power-saving switch introduced in this time, when the daytime or the light is bright, the power-saving switch is turned off, the light is not bright; when the night or the light is dark, the power-saving switch is in a preparatory working state, when someone passes near the switch, The footsteps, the voice, the clapping, etc. can all turn on the power save switch. After the light is on, the delay power-saving switch is turned off automatically after about 40 seconds, and the light is off.

Mechanical manual switches are commonly used in public buildings and public corridors in residential areas. Due to various reasons, many light bulbs are often brightened, which results in short lamp life and waste of electricity, causing economic losses for countries, units and individuals. Designing and researching an energy-saving dual-control incandescent lamp energy-saving automatic switch with novel circuit, safe power saving, simple structure and convenient installation is quite necessary.

The power-saving switch introduced in this time, when the daytime or the light is bright, the power-saving switch is turned off, the light is not bright; when the night or the light is dark, the power-saving switch is in a preparatory working state, when someone passes near the switch, The footsteps, the voice, the clapping, etc. can all turn on the power save switch. After the light is on, the delay power-saving switch is turned off automatically after about 40 seconds, and the light is off.

The power-saving switch also has the following major features: single-line access, which can directly replace the original manual control switch, without additional wiring, convenient for installation. The voice control sensitivity is high, and the footsteps, voices, etc. in the vicinity thereof can activate the switch. The power-saving switch adopts non-contact components and has a long service life. The power-saving switch itself consumes less than 0.5W, which is equivalent to saving electricity.

Circuit principle

The microphone MIC1 and VT1, R1~R3, and C1 constitute a sound pickup amplifying circuit. In order to obtain higher sensitivity, the β value of VT1 is selected to be greater than 100. The microphone MIC also uses high sensitivity. R3 should not be too small, otherwise the circuit is prone to intermittent oscillation, C2, D1 and D2, C3 constitute a voltage doubler rectifier circuit. Turn the sound signal into a DC control voltage. R4, R5 and photoresistor R11 form a light control circuit. When light is irradiated on R11, the resistance becomes small, and the DC control voltage is greatly attenuated. The electronic switch composed of VT2, VT3 and R7, D3 is cut off, there is no charge in C4, the one-way thyristor MCR is cut off, and the bulb is not bright. When the MCR is turned off, the DC high voltage is stepped down by R9, R10, and D4 and then applied to the upper ends of C3 and CW1 (stabilized tubes). C3 is the filter capacitor, CW1 is a Zener diode with a voltage regulation value of 12~15V, ensuring that the voltage on C3 does not exceed 15V DC voltage.

When no light is irradiated to R11, R11 has a large resistance value, and the DC control voltage is weakly attenuated. The electronic switches composed of VT2 and VT3 are turned on, and D3 is also turned on to charge C4. R8, C5 and unidirectional control MCR, D5~D8 form delay and AC switch. C4 applies the DC trigger voltage to the MCR control terminal through R8, the MCR turns on, and the bulb lights up. The length of time the lamp is illuminated is determined by the parameters of C4 and R8. According to the component values ​​given in the figure (R8 is 22K), after about 30 seconds of illumination, the MCR is turned off and the lamp is extinguished. C5 is an anti-interference capacitor used to eliminate bulb illuminating jitter.

Sound and light control power switch control board physical map

Editor's conclusion

The editor believes that this power-saving switch is more suitable for public places such as corridors, corridors, washrooms, toilets, etc. It can save electricity and extend the service life of the bulb. And it just makes up for the shortcomings of ordinary mechanical manual switch bulbs, which has short life and wastes power, and has high practical value. If you have good insights, please feel free to discuss in the comments section below. If you like DIY, you can try it, but pay attention to safety!