A capacitative touch sensor is simply a sensor that detects touch. Well, not actually touch. It somehow detects you and generates a response which the Pi can use anyway you want like a switch.
I’ve recently got a bunch of these.
Designed by Adafruit. They cost about £5 – £6. The one used in this project is the one on the right.
I’ve found that it’s best to connect it up and add the power supply last. It’s incredibly sensitive.
We used Conductive Paint to paint a picture.
A wire was connected to the picture. You can use conductive sheet or anything that conducts – even playdough can work.
Connect the wire to the input. On the opposite side, connect a wire to one of the Pi input pins (5,7,8, 10,19 ,21,22,23
24,26,) or one of the Arduino analog inputs.
Repeat for the other inputs. Connect the ground to the GROUND and the VCC to the Power. I’ve used 3.3 V.
To test, put your hand over the conductive device. You should see an LED come on on the device. Remove your hand and it goes out.
If you read the sensor value for the Pin, the default is 1 and if contact is made, the sensor reads 0.
Use this sensor value as you want in Scratch GPIO or Scratch for Arduino