Remote control circuit integrating light, magnetism and touch control

This is the schematic diagram of the power-saving switch circuit integrating "three controls". After power on, the three-control switch is in the waiting state, the IC (NE555) outputs
low level , and the relay K has no power, HI. not bright.
    1) Light control principle: Rl; is a photosensitive resistor. Under strong light irradiation, it has low resistance and large photocurrent. If the ⑥ terminal is high level, about
7.8V, and the ③ terminal is low level, the light not bright. When there is no light (at night), the dark resistance of the photoresistor Rc is very large, and the dark current is very small, so that the ⑥
terminal of NE555 is low level, about 1.8V, then the ③ terminal is high level, and K has electricity, then the The normally open contact K on T-time is connected and HL lights up.
    2) Magnetic control principle: The magnetic control circuit uses a magnetic reed tube. Under the action of magnetic force, the spring leaf is attracted and short-circuited RP2, so that the ⑥ terminal of NE555 is
low level, about 1. 2V, then the output terminal ◎ terminal is High level leads to conduction, making the relay K coil energized, and the normally open contact K turns on the lamp
HL and lights up.
    3) Touch control principle: The frequency range of the electrical signal emitted by the human body is 0-5kHz, and the output voltage is from microvolts to millivolts. It is a weak
voltage. After observation with an oscilloscope, there are many harmonic components. When a person touches the metal sheet M with his hand, it is equivalent to providing a signal to the VT base.
After the current is amplified, it is sent to the TWH8778 high-power drive switch integrated circuit, so that the ⑥ terminal of the NE555 is low current, and the ③ terminal is high voltage. Peace ,
the future working status will be the same as before. Therefore, in daily use, it lights up when touched by hand, and can also be used as an alarm.
    (2) Component selection transformer T is 200V/20V; K is made of JRX-13F, the DC voltage is 12V; S is a switch button, and other
components are shown in Figure 9-17.
    (3) Production and debugging According to the circuit schematic shown in Figure 9-17, a matrix printed circuit board can be purchased in the market
. The components are welded in the corresponding order according to the schematic diagram, and the transformer is fixed on the bottom plate of the chassis. The power switch S, the metal piece M, the photoresistor and the reed switch K are fixed on
the front panel. The fuse tube is fixed on the back panel, the power incoming wire is connected to the bulb, and the outgoing wires are introduced or led out through holes on the back panel.
    This circuit can generally work normally as long as the components are of qualified quality and the welding is correct. When debugging, first turn on the power switch S,
operate the three switch circuits respectively , use a multimeter to measure the voltage of each key point, and if possible, use an oscilloscope to observe the waveform of each point. The delay time can be changed by adjusting the RP value
. This circuit has diversified control methods, uses low voltage to control high voltage, and works stably, reliably, responds quickly, and operates without errors.
The prototype has been made and is working well.