Capacitive sensors, which measure the electrical capacitance of the human body, underpin the touch-sensitive displays of most modern smartphones and tablets. The way they operate can be a little hard to grasp, however, which is why we were thrilled to find a guide from Instructables user 'ohneschuh' to creating capacitive sensors for the Arduino. Built from nothing more than aluminium sheet, plywood and metal washers, the five-zone sensor provides reliable capacitance readings on both battery and mains power without the user ever having to physically contact the metal. As a low-cost alternative to a series of switches, the project shows promise and works with the official Arduino CapSense library.
Capacitive sensors are an elegant way to control an Arduino using the Capacitive Sensing Library. But the sensitivity and error tolerance depend strongly on the hardware (sensor) design.