USB extension over Cat5

I want to be able to have my arduino (duemilanove) a good ways away from my computer so I was considering buying USB over Cat5 extension dongles from Deal Extreme (I would post a link but this is my first post and YaBB 2.2.3 wont let me).

What I don't know is if I can still power the board via USB if this device is used. Could I just use battery power and still be able to send data to, let's say, Max?

The review for that device indicate that it does pass power through, however for a long run with a lot of power drawn at the other end the voltage drop over the length of the cable may become problematic. You can calculate voltage drop based on the current drawn by your Arduino and attached devices times the total resistance of the cable. (You should be able to look up the resistance per unit length of the cable you use, multiply that by the length *2 (you have to account for the cable from computer to arduino and from arduino back to computer!). )

If it looks like the voltage drop will be too great, you can always run the Arduino from an external supply. If you don't have a receptacle near the remote location you could pull a power cable alongside the cat5 (maybe 16AWG lamp cord or somesuch) from a 9V wall wart near the computer to the arduino's VIN.

Thanks a lot. So if an alternative power supply other than the usb cable is supplied, the duemilanove will automatically use it?

Have you thought about going wireless or bluetooth for your arduino? Bluetooth will be much more expensive, but some cheap wireless modules can be had. Here's some from sparkfun - You'll probably need to use the VirtualWire library with them, but they've been working for me fairly well so far. (After I found that library)

Wow, thanks. I had thought about bluetooth but those other transmitters look good. I would like to send data both ways however.... I will do some research. But thanks again!