This shouldn't be too hard with a PIC 16F84.  I have the Matrix Multimedia
development system with the C2C compiler.  In this system is a tutorial
program that takes the student through progressively more difficult examples
with a 16F84.  Anyway there is an example of a stopwatch program that
displays the running clock count in seconds and tenths of seconds on a four
digit 7 segment LED display.  It uses an interrupt from a timer that is
scaled to generate an interrupt every 0.1 seconds.  The time is counted up
at each interrupt and then displayed in four digits.  I have verified that
it is a rather good and accurate stopwatch.  The code is written in the C
language but you should be able to convert it to basic.  Contact MM at
http://www.matrixmultimedia.com/  and ask for a copy of the "EX 4.7
Stopwatch with stop/start" by Rob Miles.  MM is located in the UK.

Marlowe Cassetti
Penrose, CO  USA


"dario" <keygrand@libero.it> wrote in message
news:5ad82989.0409200057.5f149877@posting.google.com...
> Hi,
>
> I want read precise time elapsed between two flash of a red led and
> show this time on a 8/16 char matrix display. The value has to be very
accurate.
> Time range goes from 0.2 sec to 15 sec.
>
> I would like do this by a 16F84 in basic language  (picbasic pro
> compiler)
>
> Im a VB programmer and Im a newbie in a microcontroller programming
>
> Any suggestion for code and circuit for phototransistor ???
>
>
> Thanks

Hi,

I want read precise time elapsed between two flash of a red led and
show this time on a 8/16 char matrix display. The value has to be very accurate.
Time range goes from 0.2 sec to 15 sec. 

I would like do this by a 16F84 in basic language  (picbasic pro
compiler)

Im a VB programmer and Im a newbie in a microcontroller programming

Any suggestion for code and circuit for phototransistor ??? 


Thanks