Simple medium range (portable) wireless comunicator

Hi,

I run a research study and I have a pretty straight forward idea I’d like some advice making a reality.

I have a computer room with 8 computer stations all connected to the internet. I have a research assistant who helps people as they use the computers but she works in another office 500 ft away. She also moves around a lot during the day. When people finish each computer task they have to get up, walk down the hall and then knock on her door and wait. I want to build a low cost system that allows me to put a button box next to each computer station that people can activate when they’re done, wirelessly signaling a portable unit the research assistant can carry around with her so that she knows to go and check on them. Basically a wireless flight attendant call button like they use in airplanes.

My question is, what’s the most straight forward way to do this? I’ve used arduino systems before and I imagine using a couple Xbee pro units might do the trick. How hard would it be to program these though? I’m willing to spend a bit more money to get something more robust and easy to configure. Would I need to create a mesh network of the Xbee units. It also occurs to me that I could do something via the computers stations themselves using the internet. There’s already a strong wireless network throughout the entire building. But I feel like that might get complicated.

I also thought amount trying to set up some way of sending an SMS text via the computers’ internet connection to a cell phone that the Research Assistant would carry. Would that work? How might I go about setting that up?

thanks in advance for any advice!

Is the research assistant’s PC on the same network as the others (students)?

or Do they have email to one another?

Why not use a set of small, cheap-o walkie-talkies, and fix one to the computer room wall?