A keypad is often needed to provide input to an Arduino system, and membrane-type keypads are an economical solution for many applications. They are quite thin and can easily be mounted wherever they are needed.
This is a very simple example, but I think you can see how easy it is to get keypad input to your Arduino program. You can use this type of input for many different projects, including:
- Door lock
- Input PWM
- Alarm clock
- Security lock