Capacitive touch is a simple means to detect user input by measuring the dielectric constant. If it is different to a baseline measurement then it can be used as an input. In the past, we have used an MPR121 touch sensor to trigger an event using a Raspberry Pi Pico. The MPR121 is a dependable Stemma QT sensor that comes in various form factors for crocodile clips and standard wire gauges. We love it so much that we put it on our list of best Stemma QT and Grove add ons page. But is there a way to do it without using a sensor board?
Using just a piece of wire and a 1 Mega Ohm resistor in a banana, we can create our own touch interface and have a healthy snack. In this how-to, we will use the banana to toggle an LED on and off.
