Power Loss with each shield?

Is there a drop in voltage with each shield stacked?

I have a relay shield that powers up from the Arduino UNO, however it has an Xbee socket in which I've dropped a WiFly module. The Module does not power up, unless I move the AC power cord to the AC power socket on the relay shield.

The WiFly module needs 3.3v, and when I test the voltage at the input, it reads 2.3v when powered from the Arduino.

So, long story short: I may just have to use an Xbee shield and stack the relay shield on top. But if there's going to be a drop in voltage that causes one or the other to not operate, then I need to seek an alternative solution.

Lance

llhetlet: Is there a drop in voltage with each shield stacked?

I guess it really depends on the shield, but generally no. Most shields are just through-connections.

llhetlet: But if there's going to be a drop in voltage that causes one or the other to not operate, then I need to seek an alternative solution.

You probably have a Power issue.

Xbee, WiFi, and Relays sound like a lot of current consumption. How much current is your supply rated for and how much current do each of those modules draw?