Have you seen the Makey touch keyboard simulation? MaKey MaKey is a very simple circuit board that can make any objects as a computing input device.That’s to say, it can make stairway into a piano, bananas into a keyboard, plasticine into a joystick or even your families into a musical synthesizer.The principle is simple. It uses ARDUINO microcontroller to simulate a keyboard, and lead out several keys, replacing the switch with touch key.This Touch Key USB Shield is developed by KEYESTUDIO.
The shield uses touch input, namely, a double-contact switch, leading out touch port and ground connected to two touch electrodes. Because of body-resistance, when you touch the two electrodes, there is certain current flowing through between them, so can detect the touch event through the current detection.
More reference see the keyestudio Maker Touch Starter Kit.

Specification

• Compatible with UNO R3 and MEGA 2560 control board.

• XP and win7 system Drive-free auto-identification.

• Identify six buttons at most.

• Operating voltage: DC 5V.

• Can set the 6 buttons output in the code.

• Onboard comes with 2 anti-reversed interfaces, used to connect other devices.