Common control circuit generally have the following types: voice, light control, radio remote control.
voice is to use voice to control the object moves, the general electret microphone or piezoelectric sensor to pick up the sound as, after driving through the amplification level electronic circuit switching. In order to prevent outside interference with the audio, you can control the use of ultrasound, but there are also deliberately used to control audio, such as with a child to control the frequency of the sound of laughing and
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simple single-channel light control circuit is to use the photodiode after the resistance to change by the light that changes the state of electronic switch, sensor photodiode, phototransistor, photoresistor, light-sensitive cells, etc. (early production of glass closed-shell system transistors, scrape out the black shading the paint is a good photodiode). The light source can be either visible light, infrared, etc. can also be non-visible light, different photosensitive elements have different spectra. Complex of the light control circuit is able to complete the multi-channel analog switch or change in control, the application is extremely broad, we can say everyone has. Because the TV with remote control, stereo amplifier, VCD, VCR and
AT24C02N-10SI-1.8 suppliers and other home appliances remote control using infrared light remote control are typical cases. There are many residential building in the corridor lights are used a combination of light control and sound control circuit, the use of passing footsteps were issued, humorous Finals or other sound to trigger the voice-activated electronic switch lighting, light control circuit makes the automatically turn off lights during the day to stop responding.
radio remote control circuit or optical circuit than the voice control circuit is more complicated, but also farther away from control of its main features, light control, sound control circuit generally only a few meters to ten meters away from the role, and radio-controlled depending on the application can close the zero meters, far beyond the Earth can reach the space! It consists of transmitter and receiver circuit composed of two parts, the transmitter when the receiver receives radio waves emitted after the drive electronics switch circuit. So its transmitting frequency and receiving frequency must be identical. According to the emission of high-frequency waveform has amplitude, amplitude modulation, frequency modulation, digital pulse transmitter, according to its control of the number of single-channel remote control switch and multi-channel remote control.