It occurred to me tonight that I have a solution for monitoring temperatures that some others here may appreciate.

I use an iButton plus thermometer to monitor and control the temperature in my bird room. This same technique could be used to monitor the heat inside a projector and to shut the projector down when temperatures exceed a specified amount.

Here's what I'm using:
1. iButton reader (I use an older serial model but the thermocron kit should work also.
2. thermometer button (the thermocron can get the current temp also but I think the non-thermocron slightly more accurate)
3. mtempd (a UNIX daemon that monitors the reader and takes action on alarms. Technically, it's used primarily for graphing the temp stats to MRTG (multirouter traffic grapher) but it the action on alarm feature is awesome.)
4. X-10 interface (either firecracker or other computer x-10 interface works)
5. x-10 on-off device (can be either regular wall plug, lightswitch, etc.)

basically, the thermometer ibutton is read by mtempd. If mtempd senses an alarm condition, it can execute an external program. This external program would send an x-10 signal to power off the projector.

Since I have all the parts handy, I'll build it into my pj as I go along. If anyone here is in NoVA or the Rockville, MD area, send me a message if you want help integrating this into your own projector.

For an example of my current use of it, check out http://birds.chasingashley.com/

Cheers,
WH