Infrared automatic hand washing machine four

Circuit Operation Principle The infrared automatic hand washing circuit consists of a power supply circuit, an infrared transmitting circuit, an infrared receiving amplifying circuit and a decoding control circuit, as shown in Figure 9-122.

The power supply circuit is composed of capacitors C1, C2, a resistor R1, a Zener diode VS, and a rectifier diode VD.
The infrared transmitting circuit is composed of resistors R2, R7, an infrared light emitting diode VL, and a 5-pin internal circuit of the transistors V1 and IC2.
The infrared receiving and amplifying circuit is composed of a resistor R3-R6, a capacitor C3-C5, an infrared phototransistor V2 and an operational amplifier integrated circuit ICl.
The decoding control circuit is composed of an audio decoding integrated circuit IC2, resistors R8, R9, capacitors C6-C8, solid state relay KN and varistor RV.
After the AC 220V voltage is stepped down by Cl, VS regulated, VDl rectified and C2 filtered, 6V DC voltage is provided for the whole machine.
After IC2 is powered on, its 5 pin outputs a 6 kHz square wave pulse signal. After the signal is amplified by V1, the VL is driven to emit modulated infrared light.
Normally, V2 does not receive the infrared light emitted by VL. The 8 pin of IC2 outputs a high level, KN does not conduct, and the electromagnetic water valve YV does not work. When the hand reaches below the hand washing faucet, the infrared light emitted by the VL is reflected back by a human hand, and the V2 receives the reflected infrared light and converts it into an electrical signal, which is amplified by IC1 and decoded by lC2. , output low level from the 9 pin of IC2, so that the circuit inside KN is turned on, and YV is discharged. After removing the hand from the hand washing device, V2 can not receive the infrared light emitted by VL and is in a high resistance state. The 8 pin of IC2 becomes high level again, the circuit in KN is turned off, and YV stops working.
Component selection
Rl-R9 uses 1/4W metal film resistor or carbon film resistor.
RV uses a 390V varistor.
Cl selects a CBB capacitor with a withstand voltage of 450V; C2, C3, C7 and C8 select aluminum electrolytic capacitors with a withstand voltage of 16V; C4-C6 uses monolithic capacitors or polyester capacitors.
VD selects 1N4007 silicon rectifier diode for use.
VL uses SE303 type infrared light emitting diode.
VS selects lW, 6.8V silicon steady voltage diode, such as 1N4736 and other models.
Vl selects S9013 or S9014 type silicon NPN transistor for use; V2 selects 3DUl2 type infrared phototransistor (also can use VL and V2 together with an infrared optical coupler).
ICl selects μA741 type operational amplifier integrated circuit; IC2 selects LM567 type phase-locked loop audio decoder integrated circuit.
KN selects JGX-2FB solid state relay.
YV selects AC 220V electromagnetic water valve.