AVR-Chat

A tiny26 programmed with BASCOM would do nicely.  The free demo is enough to
do it all on a Tiny26 (www.mcselec.com)  You get a semi-accurate 16mhz
internal oscillator which would give you plenty of resolution over 1"  and
Bascom has built in LCD libraries which would get your display going very
fast.

I would just spin waiting for the first event, then loop incrementing a
counter until the next event, then divide the count into some number to get
furlongs per fortnight, or whatever units you want.

You can get fancier by using a timer and grab the current count when the
events occur.  That way you get more resolution.  Say, run the timer at
clock/16, or 1us/tick.

Cheers!

-----Original Message-----
From: William Nachefski

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?