Serarate Power for Ethernet Shield

Other Hardware General Electronics
1

I've got an Arduino Duemilanova clone connected to an Ethernet shield which serves a web page that lets me send X-10 commands from a CM17a Firecracker connected to the Arduino.

They are not stacked, but rather are connected by a ribbon cable.

The thing works great when powered from a 1 Amp 5 VDC power supply.

Issue I'm having, is that when device is powered by the computer USB port (for testing and development), there is insufficient power for effective X-10 commands to be sent. The sketch works fine and connects to the internet as desired.

Question is:

Would there be a problem if I were to power the Ethernet card separately from the Arduino.
That is: Common ground, Arduino 5 volts from USB, and Ethernet card 5 volts from it's own wall wart.

I can't see that there would be any danger to hardware, but I'm not an EE, so I thought I'd ask.

Sorry if question too elementary.

Bob W.

2

That is fine and dandy, and is common practice to boot.

3

majenko:
That is fine and dandy, and is common practice to boot.

Very odd.
With separate power supplies, web page doesn't come up on browser.

Should I be powering up Ethernet Shield first, then applying power to Arduino ?
Resets are still connected. Would think shield would reset when Arduino boots.

4

Some discussion from the past.