ronwer Posted April 25, 2006 Report Share Posted April 25, 2006 Hello,I have not been succesful finding an appropriate schematics for a small science project I want to built.It's actually very simple: I want to measure the drop time of different objects through a metallic tube (copper).The objects will vary from a stone, an ordinary magnet to the strongest possible neodymium magnet.At the top and end of the tube I want to mount IR-detectors that will respectively start and stop the counter, which result should be shown on a (old-fashioned) LED-display.I want to use as much as is possible old stuff I have lying around, or cheap CMOS IC's.An ordinary stopwatch as I found on this site isn't fast enough, but anything which comes close to one of these two schematics would be wonderful.Any help is appreciated!Ronald WernerNorway Quote Link to comment Share on other sites More sharing options...
logan_dslasher Posted April 26, 2006 Report Share Posted April 26, 2006 Hi ronwer! ;Dhttp://www.cip.physik.uni-muenchen.de/~wwieser/elec/freqcnt/oscillator.htmlwould that help? hope so.. Quote Link to comment Share on other sites More sharing options...
ronwer Posted April 26, 2006 Author Report Share Posted April 26, 2006 Hi,See what you mean. The signal could be used to drive a simple 4-digit counter (74c926) I found some place.But it's still a bit complicated. I need to find a good solution for the sensors that start and stop the counter.Accuracy is not a first concern, the osciallator could also be a 555 I adjust in such a way that the result is aceptable.It's the hopefully big difference between normal objects and the neodymium magnet that do the trick.Anyway, thanks for you help.Ronald Quote Link to comment Share on other sites More sharing options...
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