If you need a lot of inputs and/or outputs, this is your solution! The Mux (Multiplexer) Shield adds the capacity for up to 48 inputs or outputs on the Arduino and Arduino Mega. Using three Texas Instruments CD74HC4067 Analog Multiplexers, the Mux Shield makes it possible to have 48 analog/digital inputs or digital outputs in many combinations. The Mux Shield comes with 5V and Ground headers so you'll have power available to each input or output and comes with stackable headers installed. The source code below will get you started!
• 48 analog inputs/digital inputs/digital outputs (in combination)
• Vcc and Ground header strips (each input/output pin has a dedicated Vcc and Ground)
• Reset button
• PIN 13 LED and Power LED
• Stackable headers (plug directly into Arduino and add more shields on top)
• Arduino Mega compatible
• Requires digital pins 2,3,4,5 and analog pins 0,1,2 – 48 inputs/outputs for the price of 7 pins