Inputs after installing Shields?

I'm new to the wonderful world of Arduino and am really enjoying the process of building my project. I'm a Solution Engineer at and am working on a demo that simulates physical events that generate processes within our applications. Think something like a temperature that rises past a certain threshold, which creates, routes and escalates a Case in Salesforce.

I've assembled and installed an Adafruit Wifi board (directly on top of my Uno) and an Adafruit RGB Display board (on the top of the stack) and everything is working perfectly, however, I now have no ability of plugging the LEDs, piezo speaker and temperature probe I'd like to use.


  • Can I install stacking headers on the display shield to use the pins I need?
  • If I install my shields on an Arduino Mega will I have physical access to the inputs/outputs I need?
  • Can any recommend a method that will allow me to plug this extra stuff in?

Any advice/suggestions are greatly appreciated!

Combining shields and Arduino boards requires to check the pins and the hardware use of the Libraries.

Could you give links to the products ?
This wifi shield ? Adafruit HUZZAH CC3000 WiFi Shield with Onboard Antenna : ID 1491 : $39.95 : Adafruit Industries, Unique & fun DIY electronics and kits
This RGB display ? RGB LCD Shield Kit w/ 16x2 Character Display - Only 2 pins used! [NEGATIVE DISPLAY] : ID 714 : $24.95 : Adafruit Industries, Unique & fun DIY electronics and kits
How did you attach the RGB display to it ?

I think that wifi shield uses SPI bus pin 10,11,12,13, and also pin 3,4,5
The RGB display uses pin SDA and SCL (they are also pin A4 and A5 on Arduino Uno).

The RGB library probably won't use any timers in the microcontroller. So those two boards should work fine.

You can use the other pins. Perhaps there are stackable prototype boards. That wifi shield has already a prototype area. You can solder extra components there.

When using the wifi library, the SD library, a DS18B20 library (the DS18B20 is the temperature sensor that you need 8) ).. That might not fit in the memory of an Arduino Uno.
The Arduino Mega has more memory, but then you should check if those shields are compatible with the Arduino Mega.

One way to connect external devices is a prototyping shield with stacking headers. You can put that below a shield that doesn't have stacking headers to gain access to any unused pins.

Or a screw shield, put above Uno/Mega and then other shields above it.

Good suggestions - thank you. I also learned that I can remove from my 'stack' and just wire a few pins plus power and ground to create a remote display.