Arduino Workshop, 2nd Edition

11 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 statement
• 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 device with a keyboard. For example, you might like 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 11-1.

Figure 11-1: A numeric keypad

One of the ...