ITEM NAME:1Pcs Knock Sensor Module With Led Ky-031 For Arduino Pic Avr Raspberry MO FT Knock sensor module and a digital 13 interface, built-in LED build a simple circuit to produce percussion flasher. Interface comes with digital LED, will knock sensor connected digital 3 interface, when percussion sensor senses measure to percussive signals, LED flashing light. Routines source code: int Led = 13;// define LED Interface int Shock = 3;// define the percussion Sensor Interface int val;// define numeric variables val void setup () void loop () { val = digitalRead (Shock) ;// read digital interface is assigned a value of 3 val if (val == HIGH) // When the percussion when the sensor detects a signal, LED flashes { digitalWrite(Led, LOW);.Knock sensor module and a digital 13 interface, built-in LED build a simple circuit to produce percussion flasher. pinMode (Shock, INPUT) ;// define knock sensor output interface. pinMode (Led, OUTPUT) ;// define LED as output interface.