On Sat, May 31, 2008 at 8:13 PM, Jinx wrote: > Honestly, I think sound detection is too problematic I think that too, but it can be tried and if successful then it's very cheap and dead easy to install. A microphone based glass break sensor that works in rooms of all sizes, with different types of windows, and can tell the difference between a glass cup breaking and a window break uses an 8 bit micro. So I imagine there's a way... > How about .... > > IR transmitters on the doors. Their outputs are picked up by > a centrally-located receiver. If a door opens, its transmitter > will no longer be received, as it's now pointing outside the car. > Could all be fixed in place with magnets > The prototypes will have pressure, light, microphone, acceleration, GPS, and switch inputs for testing various algorithms and combinations. If needed, the production part will have multiple methods, but going from ideal to non-ideal: 1. Just a box that plugs into a 12V outlet 2. A box that plugs into a 12V outlet with a single device (light or switch) that can be placed very non-critically and still sense the desired status change (dome light going on, driver door opening, etc) 3. A box that plugs into a 12V outlet with several light or switch sensors taped and wired to various locations 4. A box that plugs into a 12V outlet that also taps vehicle wiring elsewhere, or requires removal of any part/trim/etc to place a sensor. The IR transmitters sound interesting, and would lie somewhere between 1 and 2 above, but might be tricky to place so that they aren't also blocked by the passengers or cargo. Could have other drawbacks, but I'll keep it in mind. Given that we have a GPS on the final device, then some situations can be filtered (during movement you don't need a trigger, so can ignore wind gust on the freeway for a microphone or pressure sensor, for instance). -Adam -- EARTH DAY 2008 Tuesday April 22 Save Money * Save Oil * Save Lives * Save the Planet http://www.driveslowly.org -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist