I would like to have a stand-alone board to put in the laser tag modules instead of an arduino. This would allow students to use the arduino that they use in class for other projects while keeping the laser tag module intact. Right now I have two alternatives:
Moteino: Cost: $18.95. Uses surface mount components for a really small footprint (1.3x0.9 inches), ATMega328P processor, RFM12B tranceiver. This is the lowest cost module that I could find (as opposed to the JeeNode, which is 18 euros, and has a much larger footprint). I would need an FTDI adapter (or just use the one in the arduino to program it) to program the module, but that's fine. The Moteino also has a version without the RFM12B, which is $12.95.
Update: Low Power Lab is working on an ATMega32u4 based Moteino called the Moteeino Leo, which will probably be less expensive (since it's USB native). Keep an eye out for this.
Freakduino: Cost: $33. Freakduino is an open source arduino clone with an on board 2.4GHz radio (the Atmel AT86RF230). It has a great datasheet, and is a bit bigger than a standard arduino. It's a little pricier, but I like that it can have a longer range by adding an antenna.
miniSWARM: Cost: $25. miniSWARM is an open source arduino compatible with a 2.4GHz radio built into the chip. As of this posting, it is on Indiegogo for crowd funding. It can be used to build a mesh network and is based on the ATmega128RFA1. They are also giving away some miniSWARMs away on their website. This module has much more capability than I need for my application, but it may be useful if I want a mesh network and a much more complicated game.
Note: Both of these alternatives have built in radios for communicating with a central hub, which would keep track of tags. I could not have a wireless module and have all the communication between the central hub, bases, etc be done through IR. It'd be more protocol to write, but I can do it. Just not sure if I want the added flexibility of getting data from players as they play the game.
Later Note: The Waspmote is a commercial wireless sensor node based of the ATMega1281, which is arduino compatible. ATMega processors can be used for real, commercial applications. Fun fact to know.
Processor Note: So, I'm using an ATMega328p when I don't need that much functionality. I mean, I need 1 hardware timer, at least 10 I/O pins (if I put a 7-seg LED on it, or other peripherals), and some program space. But switching to an ATTiny could prove prohibitively complicated in the context of an introductory course. I don't want to have people programming an AVR with an arduino just to get a smaller microprocessor. It's a nice thought to use something with less capability because I don't need the capability, but if I end up expanding this project, it'll be nice to have excess program space and I/O pins to play around with. And who knows, maybe I'll need another hardware timer.