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
To simplify and organize your wiring setup, we recommend using a Screw Terminal Block Shield for Raspberry Pi. This shield ensures more secure and manageable connections, as shown below:
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!