Smart Sensor For Shock And Vibration Detection

The Smart Sensor for Shock And Vibration Detection operates as a discrete analog circuit powered by a 3V CR2032 coin cell battery. The core of the detection mechanism is the SW18015P vibration sensor switch (SEN1), which acts as a mechanical switch that closes or breaks contact when subjected to physical movement, shock, or vibration. When undisturbed, the sensor remains in its default state. Upon experiencing physical shock, the internal spring mechanism touches the inner pole, momentarily completing the circuit path. This triggers the discrete transistor switching stage. The 2N2222 NPN transistor (T1) functions as a solid-state switch. When a vibration event triggers the input, base current flows through resistor R2 (3.3-kilo-ohm), which limits the current into the base of T1. Once the base-emitter junction is forward-biased, the transistor turns on, allowing current to flow from the collector to the emitter. This completes the circuit for the 5mm yellow LED (LED1) and its current-limiting resistor R1 (330-ohm), causing the LED to light up and visually indicate the detection of a shock event. Electrolytic capacitors C1 (10μF) and C2 (4.7μF) are placed across power rails to help stabilize the supply voltage and filter out high-frequency electrical noise, ensuring reliable switching behavior from the transistor without false triggers.