David C. Kerber wrote: > Remember what the original suggestion was: have the device wake > up for a few seconds once a day and send a message as to where it > is (or maybe only send that message if it's not where it's supposed > to be).
Yes, I remember the original suggestion; I don't know what the GPS performance is, but most GPSs have a cold-start TTFF of a few minutes, so the "few seconds" is already "a few minutes". I'm not necessarily saying that the problems are necessarily insurmountable, just that I think that there might be a bit more of a problem with power consumption than you think. Of course, we also have the problem of getting a decent GPS fix, since if it's stolen, it will need to get enough signal to report its position, and if it's being stored inside a building, that's going to be very difficult, even before you take the possibility of a metal-framed bike into account. > Considering that a typical bike-mounted gps (Garmin Edge 305, for > example) can run for several hours on 3xAA batteries, including gps, > cadence, heartrate and speed sensors, along with a continuous display, > I think a couple of AA batteries would power this thing for several > months or even years, at a few seconds per day. I doubt that the cadence/heartrate/speed measurement is going to have any significant effect on the power consumption - most non-GPS cycle computers will do that for months if not years on a coin cell. It's the GPS and GSM that suck the power. > And if you can tie it in to Shimano's DI-2 power pack, it will have > its power routinely recharged by the user every few weeks for other > purposes any way. True, but then it becomes more difficult to hide inside the frame, and get wires into/out of the frame. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user