Sparkfun Button Pad 2x2

This is sample code to drive the Sparkfun Button Pad 2x2 from an Arduino.

It lights up the LEDs different colors each time you press it.

Hardware

You will need:

• Button Pad
  • Button Pad 2x2 (silicone pad): Sparkfun || Little Bird
  • Button Pad 2x2 PDB: Sparkfun || Little Bird
  • RGB LEDs (Common Cathode): Sparkfun || Little Bird
  • Diodes 1N4148: DX
  • Top bezel: Sparkfun || Little Bird
  • Right angle pin headers: Little Bird
• On the breadboard
  • 100 Ohm Resistors x4: DX
  • Arduino (I used a Nano): DX
• Wires: DX
  • What you get for this depends on your use case, but I used these to plug into my breadboard.

Theory

To drive the LEDs we are going to use PWM/AnalogWrite to drive the common pin on each LED, then cycle through each color one at a time. You need to put the resistors where it will not be supplying current for more than one LED at a time, so we put it on the common pins of each LED.

For reading the buttons, I used the Keypad library. It handles all the debouncing and pin IO for you, which is handy.

Wiring

PCB Label	Arduino Pin
SWITCH	A0
SWT-GND1	A1
SWT-GND2	A2
SWT-GND3	A3
SWT-GND4	A4
LED-GND1	3
LED-GND2	5
LED-GND3	6
LED-GND4	9
RED	4
GREEN	7
BLUE	8