Raspberry Pi - Touch Sensor - Piezo Buzzer
This tutorial instructs you how to use Raspberry Pi and touch sensor to control piezo buzzer. In detail:
- Raspberry Pi produces a sound when the touch sensor is touched.
- Raspberry Pi ceases making noise when the touch sensor is not engaged.
- Raspberry Pi plays a melody when the touch sensor is touched.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.
Additionally, some of these links are for products from our own brand, DIYables.
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
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!