Dan,

I guess you did'nt quite understand Miles' plans.
I guess, he wants to control the brightness of the Headlight with PWM.
And if that is the case  I suggest that Miles can go for an even
higher frequency. May be a couple of Khz. Since as a rule, the Higher
the frequency, the greater the efficency.

Jeethu Rao
www.jeethurao.com

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Dan Michaels
Sent: Friday, June 29, 2001 5:31 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]: Modulating a headlight


Miles McKinnon wrote:
>I am building a motorcycle headlight modulator using a PIC to monitor
>ambient light and a few other things.  Anyway, the PIC has to modulate the
>headlight ( ~ 4Amps) at a arount 240Hz or so.
>

Miles, 240 hz is a little high, if your intent is to have
people see the flicker as a warning signal. The flicker
fusion frequency of humans is about 20 hz, so even 24 hz
may be too high. Might be good for insects however.

I think somewhere around 4 hz is the most noticeable to
humans. You might do a web search on "psychophysics".

good luck,
- dan michaels
www.oricomtech.com
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