Features:
1) MAXIMUM TIME: 99 MIN, 99.9999999 SEC ...Really just a display limitation
2) MINIMUM TIME: 0.0000522 SEC also a display limit at 9999.999998 MPH
3) Time Resolution: 200 nS = 0.0000002 SEC
4) Input single PULSE to Pin RC2
5) Displays Measurement and resets awaiting next pulse.
6) Data is sent out to 57600 N-8-1 Serial terminal on Pin RC6
7) Status LED shows when pulse is being timed.
Comments:
This was an experiment in precision of the code.
No oscillator is really this accurate.
Probably pretty close for relative measurements.
But Not for absolute measurements
Currently the speed is based on fixed distance of the optical sensors.
they are fixed and hard coded at 6.000 inches.
The circuit I use to derive the pulse is here:
http://www.picbasic.co.uk/forum/showthread.php?t=12614
Future Plans:
1) Add additional speed units (M/S, KMH)
2) Add user menu to set gate distance and displayed units
3) Add an oscillator correction factor after comparing it to bench-top timer.
4) Write settings to Onboard EEPROM
5) Try a 40 MHz crystal oscillator or other High accuracy clock
6) Build a thermal oven for crystal oscillator ...
Enjoy,
--Bob
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