Children’s Circuit Learning Kit Touch Vibration Car Anti-theft Alarm Motorcycle Anti-theft Alarm DIY Kit

Product Model: TJ-56-107

Power Supply Voltage: 3V (DC power supply)

Board Size: 43*31mm

Product Description:

This circuit simulates the principle design of car and motorcycle anti-theft alarms, with touch delay alarm and vibration delay alarm functions. That is, when there is a human touch sensing signal, the alarm is triggered. After the trigger signal is cancelled, it automatically shuts down after a delay. When there is a vibration signal, the alarm is triggered. After the vibration signal is cancelled, it automatically shuts down after a delay.

The touch vibration alarm is composed of a touch trigger circuit, a vibration trigger circuit, and an alarm circuit. The 555 timer circuit U1 forms a typical monostable working mode, and its transient time is determined by the values of RP1, R2, and C2. Normally, when the circuit is in a stable state, the 3-pin output of the 555 timer circuit is at a low level, and the alarm chip does not alarm because there is no power supply. When a human hand touches the electrode piece M, the noise signal induced by the human body is injected into the trigger terminal (pin 2) of the 555 timer via C1. Alternatively, when the vibration sensor S1 is momentarily activated due to vibration, both scenarios will cause an instantaneous low level at pin 2 of U1, causing the 555 timer circuit to flip into a transient state. Pin 3 then abruptly changes to a high level, powering the alarm chip and triggering an alarm sound. Once the transient time has passed, the timer circuit flips back to a stable state and stops the alarm. The length of the alarm time can be adjusted by changing RP1. The LED is a dual-color light-emitting diode. After being powered on, the green light is on and is used as a power indicator. When the alarm is on, the red and green lights are on, and the overall appearance is orange-yellow. The resistance value of R5 determines the playback speed of the alarm sound, generally 180K-240K. Note that before installing the chip, it should be installed on the alarm chip board first. The entire circuit can work with DC3-6V.