You would most likely need a high speed timer to do this. The microprocessor can read the results but I’m not sure if the built in timers would be fast enough to record the events. You would have to define the parameters regarding accuracy.
What are your acceptable tolerances?
Barry
-----Original Message-----
From: William Nachefski
[mailto:slaphappysamy@yahoo.com]
Sent: Tuesday, March 09, 2004 2:27
PM
Subject: [AVR-Chat] Speed Trap
I need some way of measuring/displaying velocity of a
projectile.
This is for my coil gun experiment. Heres
how I think I might go
about it. Two matched pair
IRdiode/phototransitor sensors, placed in
a tube one inch apart. This tube is then
slipped over the end of the
barrel. Use a AVR to start timing after first LED
beam is broken and
stop timing after second is broken. Then
make some formula to calc
feet/second and display the result by either LCD
or LED display. Any
coments on what the code might look like.
Also which AVR Should I
use? Could The Tiny serries handle this?