The sensor works on the principle of capacitive changes when a human finger is near the pad. The sensor has two types of output. The first output is called proximity output which gets activated when finger is around 2 cm above pad. Another output is touch output which gets activated when finger is just above the pad around 1mm above. Even that small distance is considered as touch. This is since your design might have a layer of plastic to protect the touch design.
You might have already seen Samsung touch mobile phone using this principle to switch off LCD to save power when you are taking phone near your ear. They use the same principle of proximity sensing using capacitive discharge. Also many modern home automation untis implements capacitive keypads which are covered by a thin plastic printed adhesive without any physical contact switch.
- Touch & Proximitiy LED Indication
- Works on 5V
- Simple to use and Low cost
- Very long operational life
- Makes excellent touch interface applications
- Capacitive principle makes it highly responsive
- Excellent alternate to mechanical switches