Arduino Workshop

Chapter 9. Numeric Keypads

In this chapter you will

• Learn how to connect numeric keypads to your Arduino

• Read values from the keypad in a sketch

• Expand on decision systems with the switch-case function

• Create a PIN-controlled lock or switch

Using a Numeric Keypad

As your projects become more involved, you might want to accept numeric input from users when your Arduino isn’t connected to a PC—for example, if you’d like to have the ability to turn something on or off by entering a secret number. One option would be to wire up 10 or more push buttons to various digital input pins (for the numbers 0 through 9); but it’s much easier to use a numeric keypad like the one shown in Figure 9-1.

Figure 9-1. Numeric keypad

One of the benefits of using a keypad is ...