In this article, we connect an KY-031 Knock Sensor to a Raspberry Pi 4
When the KY-031 sensor is subjected to a knock or vibration, the two output pins are short-circuited.
We will use Python for the example
The sensor looks like this
Parts Required
You can connect to the module using dupont style jumper wire. There is no reason this device will not work with any Raspberry Pi hardware that you have – in this example a Raspberry Pi 4 but you can use a Zero if you want a lower cost solution
| Name | Link | |
| Raspberry Pi 4 | ||
| 37 in one sensor kit | ||
| Connecting cables |
Schematic/Connection
| Pico | SENSOR |
|---|---|
| Pin 18 | S |
| 3.3V | middle pin |
| GND | – |
Code Examples
Basic example in thonny, running on the Raspberry Pi
import RPi. GPIO as GPIO
import time
GPIO.setmode (GPIO.BCM)
# Here the input pin to which the Knock Sensor is connected
GPIO_PIN = 24
GPIO.setup (GPIO_PIN, GPIO.IN)
print ("Knock Sensor test [press CTRL+C to exit the test]")
# This output function is executed when a signal is detected
def outputFunction(null) :
print("Knock Sensor triggered")
# When a signal is detected (falling signal edge), the output function is triggered
GPIO.add_event_detect(GPIO_PIN, GPIO.FALLING, callback= outputFunction , bouncetime=100)
# Main loop
try:
while True:
time.sleep (1)
except KeyboardInterrupt:
GPIO.cleanup ()
REPL Output
Tap the sensor
>>> %Run -c $EDITOR_CONTENT
Knock Sensor test [press CTRL+C to exit the test]
Knock Sensor triggered
Knock Sensor triggered
Links
https://github.com/getelectronics/PIBits/tree/master/Sensor%20Kit/KY-031%20KNOCK%20SENSOR