[Image] Automatic hand washing machine circuit diagram

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The circuit principle of the automatic hand-washing machine is shown in Figure 1. The 220V AC circuit is stepped down by transformer T to become low-voltage AC power, which is rectified and filtered to become low-voltage DC power. It is then stabilized by the three-terminal integrated voltage regulator circuit 7806 to obtain 6V DC power to supply the control circuit. H1 is a red light-emitting diode, which serves as a power indicator. N2 is an infrared receiving circuit SFH506-38, N3 is a phase-locked loop audio decoder LM567, N3 and R3, C6 form an oscillator, R3, R6 determine the center frequency of the internal voltage-controlled oscillator of N3, LM567's 3rd pin is the signal input terminal, 8th pin is the logic output terminal, and its output terminal is the OC gate output, with a maximum sink current of 100mA, LM567's operating voltage is 4.75V~9V, the operating frequency can be from a few tenths of Hz to 500 kHz, and the static operating current is 8mA. N4 is a NE555 timer, which forms a monostable timing circuit with peripheral components. Its purpose is to ensure the normal water flow of the hand washer when the human hand occasionally deviates from the infrared detection range.