Raspberry Pi - Touch Sensor - Piezo Buzzer

This tutorial instructs you how to use Raspberry Pi and touch sensor to control piezo buzzer. In detail:

Hardware Preparation

1×Raspberry Pi 4 Model B
1×Touch Sensor
1×Piezo Buzzer
1×Breadboard
1×Jumper Wires
1×(Optional) Screw Terminal Adapter for Raspberry Pi

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Overview of Piezo Buzzer and Touch Sensor

If you are unfamiliar with piezo buzzer and touch sensor (including pinout, functionality, and programming), the following tutorials can help:

Wiring Diagram

The wiring diagram between Raspberry Pi and Touch Sensor Piezo Buzzer

This image is created using Fritzing. Click to enlarge image

Raspberry Pi Code - Simple Sound

In this section, we'll program Raspberry Pi to trigger a piezo buzzer to generate a simple sound whenever you touch your finger on the touch sensor.

Detailed Instructions

  • Make sure you have Raspbian or any other Raspberry Pi compatible operating system installed on your Pi.
  • Make sure your Raspberry Pi is connected to the same local network as your PC.
  • Make sure your Raspberry Pi is connected to the internet if you need to install some libraries.
  • If this is the first time you use Raspberry Pi, See how to set up the Raspberry Pi
  • Connect your PC to the Raspberry Pi via SSH using the built-in SSH client on Linux and macOS or PuTTY on Windows. See to how connect your PC to Raspberry Pi via SSH.
  • Make sure you have the RPi.GPIO library installed. If not, install it using the following command:
sudo apt-get update sudo apt-get install python3-rpi.gpio
  • Create a Python script file touch_sensor_buzzer.py and add the following code:
# This Raspberry Pi code was developed by newbiely.com # This Raspberry Pi code is made available for public use without any restriction # For comprehensive instructions and wiring diagrams, please visit: # https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-touch-sensor-piezo-buzzer import RPi.GPIO as GPIO import time # Set the GPIO mode (BCM or BOARD) GPIO.setmode(GPIO.BCM) # Define the GPIO pin number to which the buzzer is connected BUZZER_PIN = 18 # Define the GPIO pin number to which the touch sensor is connected TOUCH_SENSOR_PIN = 16 # Set up the GPIO pins GPIO.setup(TOUCH_SENSOR_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) # Input with pull-up resistor GPIO.setup(BUZZER_PIN, GPIO.OUT) # Output try: while True: touch_state = GPIO.input(TOUCH_SENSOR_PIN) if touch_state == GPIO.HIGH: print("The sensor is touched") GPIO.output(BUZZER_PIN, GPIO.HIGH) # Turn the buzzer on else: print("The sensor is untouched") GPIO.output(BUZZER_PIN, GPIO.LOW) # Turn the buzzer off # Add a slight delay to debounce the touch sensor (optional) time.sleep(0.1) # Allow the user to stop the buzzer by pressing Ctrl+C except KeyboardInterrupt: GPIO.output(BUZZER_PIN, GPIO.LOW) # Turn off the buzzer GPIO.cleanup()
  • Save the file and run the Python script by executing the following command in the terminal:
python3 touch_sensor_buzzer.py
  • Place your finger on the touch sensor and hold it there for several seconds.
  • Listen to the sound coming from the piezo buzzer.

The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Raspberry Pi plays the melody of the song

In this section, we'll program Raspberry Pi to trigger a piezo buzzer to play the song "Jingle Bells" when you place your finger on the touch sensor.

Detailed Instructions

  • Create a Python script file touch_sensor_buzzer_Jingle_Bells.py and add the following code:
# This Raspberry Pi code was developed by newbiely.com # This Raspberry Pi code is made available for public use without any restriction # For comprehensive instructions and wiring diagrams, please visit: # https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-touch-sensor-piezo-buzzer import RPi.GPIO as GPIO import time # Set the GPIO mode (BCM or BOARD) GPIO.setmode(GPIO.BCM) # Define the GPIO pin number to which the buzzer is connected BUZZER_PIN = 18 # Define the GPIO pin number to which the touch sensor is connected TOUCH_SENSOR_PIN = 16 # Set up the GPIO pins GPIO.setup(BUZZER_PIN, GPIO.OUT) GPIO.setup(TOUCH_SENSOR_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) # Constants for note names and their corresponding frequencies C4 = 261 D4 = 293 E4 = 329 F4 = 349 G4 = 392 A4 = 440 B4 = 493 # Dictionary to map numeric values to note names note_names = { C4: "C4", D4: "D4", E4: "E4", F4: "F4", G4: "G4", A4: "A4", B4: "B4", } # List of notes in the "Jingle Bells" melody melody = [ E4, E4, E4, E4, E4, E4, E4, G4, C4, D4, E4, F4, F4, F4, F4, F4, E4, E4, E4, E4, E4, D4, D4, E4, D4, G4 ] # List of note durations (in milliseconds) note_durations = [ 200, 200, 400, 200, 200, 400, 200, 200, 200, 200, 200, 200, 200, 400, 200, 200, 200, 200, 200, 200, 200, 200, 200, 400, 200, 200 ] # Pause duration between notes (in milliseconds) pause_duration = 300 def play_tone(pin, frequency, duration): # Calculate the period based on the frequency period = 1.0 / frequency # Calculate the time for half of the period half_period = period / 2.0 # Calculate the number of cycles for the given duration cycles = int(duration / period) for _ in range(cycles): # Set the GPIO pin to HIGH GPIO.output(pin, GPIO.HIGH) # Wait for half of the period time.sleep(half_period) # Set the GPIO pin to LOW GPIO.output(pin, GPIO.LOW) # Wait for the other half of the period time.sleep(half_period) def play_jingle_bells(): for i in range(len(melody)): note_duration = note_durations[i] / 1000.0 note_freq = melody[i] note_name = note_names.get(note_freq, "Pause") print(f"Playing {note_name} (Frequency: {note_freq} Hz) for {note_duration} seconds") play_tone(BUZZER_PIN, note_freq, note_duration) time.sleep(pause_duration / 1000.0) GPIO.output(BUZZER_PIN, GPIO.LOW) try: while True: touch_state = GPIO.input(TOUCH_SENSOR_PIN) if touch_state == GPIO.HIGH: play_jingle_bells() # Allow the user to stop the buzzer by pressing Ctrl+C except KeyboardInterrupt: GPIO.output(BUZZER_PIN, GPIO.LOW) GPIO.cleanup()
  • Save the file and run the Python script by executing the following command in the terminal:
python3 touch_sensor_buzzer_Jingle_Bells.py
  • Touch your finger on the touch sensor.
  • Hear the tune from the piezo buzzer.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Video Tutorial