Suggestion: make a receiver for the sensors available for the ever-popular line of GE wireless security systems, similar to the Dakota Alert receiver.
* GE’s sensors transmit only, and do not receive (no need for two-way radio)
* Their sensors are low cost and often aesthetically pleasing as well (e.g. their best door sensor has a lifetime permanent lithium battery and looks like a tampon… http://www.gesecurity.com/portal/site/GESecurity/menuitem.f76d98ccce4cabed5efa421766030730?selectedID=1277&seriesyn=true&seriesID= you embed it in a 5/8″ diameter hole in a door jamb and then can paint over it… totally invisible)
* Their sensors are reasonably low cost ($20-$60/sensor)
* Sensors include motion, contact, continuity, freezing, flood, smoke, rate-of-heat-rise, pendant/wall panic buttons, audible glass-break, and come in different sizes and types (i.e. pet-immune motion, normal motion, etc.)
* Most of those items have interlock switches and report tampering (i.e. removal from wall, opening of case)
* Implementation is likely very simple, as all the sensors send the exact same messages no matter what they sense (a hardcoded hex device serial number plus generally one of the following message codes: ACTIVATE, DEACTIVATE, TAMPER, END TAMPER, LOW BATTERY, END LOW BATTERY, or a periodic “I’M STILL ALIVE” every 60 min or so.)
* Add lots of capabilities to INSTEON system with minimal R&D.