>From: Midgley John >John Midgley wrote ... >I've an idea for a few PIC based toys (all non-commercial!) that I've >been thinking about for a while. They all depend on an pressure sensor >of some kind, but which?. Suggestions and comments (from part numbers >upwards!) would be more than welcome:- > >2. For free-fall parachuting - you just passed 3,000' (2,000', whatever) >going too fast - BEEP! pull now! I understand that skydivers use barometric altimeters already. Anything you built would want to be VERY secure in its operation. Not subject to temperarture, EMI, flat battery, (altitude :-)) , .... I'd give this one a miss as an amateur. >3. I have a friend into model rockets - how high do they get? Estes type rockets with essentially black powder motors go from a few hundred feet with small motors and a single stage to say 5000 feet odd for a good multi stage design with multiple D motors. Then there are codes with bigger motors, e, f, g, .... (the sky's the limit :-)) then there are the reloadable chlorate motors and hybrids and finally the high performance model rocketry fans with custom built motors and even fully liquid propellants. These get (very very best case) to around 80,000 feet (one has reached about 120,000 I think). These are such expensive items that they would use time proven existing electronics. People are aiming at an amateur orbital device some time soon but pressure altimeters don't work up there :-). Most estes type rockets would be covered by a 5000' altimeter system.