Capacitive touch piezo buzzer

This project demonstrates how to set up capacitive touch sensing and simple piezo tone generation.

Here's a little Fritzing diagram that recreates Paul Badger's capacitive touch sensing tutorial on the Arduino website. I found the wiring description a little hard to follow, so hopefully this format will help others include this simple actuator in their projects.

 

Components

  • Arduino UNO (others probably work too)
  • Piezo like this one
  • 1M resistor (or higher)
  • jumper wire
  • breadboard

Instructions

  1. Wire the circuit as shown in the diagram.
  2. Download and install the Capacitive Sensing Library. (thanks kmiddleton!)
  3. Upload the code to the Arduino.
  4. Touch your finger to the resistor leg closest to pin 6. This should casue the piezo to beep.
  5. If you'd like to change the touch sensitivity, open the serial monitor while the Arduino is running this program.
  6. Touch the resistor/antenna and note the floor/ceiling of the corresponding numerical reading.
  7. Edit the sensorTrip variable in the Arduino code.

Notes

  • Badger talks about adding small capacitors but I couldn't get this to work. Check out his tutorial and see if you can figure it out!
  • Higher resistor values = more sensitivity. At the upper ranges you can get the antenna to sense at a distance, even through an insulator like paper or tape.