conduction sensors, trigger controllers

Makey Makey, I-PAC, and Bare Conductive are all trigger controllers: devices that let you turn everyday actions into digital inputs, connecting the real world to your computer. They are often used  because they make interaction tangible and playful.

• Makey Makey works like a keyboard or gamepad. By connecting alligator clips to conductive objects (fruit, foil, people), touching those objects completes a circuit. Each touch becomes click on the computer.

• I-PAC (Interface for PC to Arcade Controls) is like a MakeyMakey but with all the options your keyboarrd has.

• Bare Conductive lets surfaces themselves become interactive — conductive paint, materials or objects objects -Touching or even approaching the area sends signals that can be used to trigger sounds, visuals, or other digital outputs. 
  

BC sends values whereas MakeyMakey & Ipac send trigegr signals (0/1).
What they share is the principle of conductivity: the body or a conductive material closes a circuit, creating a trigger.