Newsgroups: comp.robotics
Path: brunix!sgiblab!sgigate.sgi.com!odin!twilight!sgi!wdl1!mail!cps233!dombrows
From: dombrows@lds.loral.com (Brian Dombrowski, 5424)
Subject: Re: Anemometer speed - help
Message-ID: <1994May18.132543.9059@lds.loral.com>
Sender: news@lds.loral.com
Reply-To: dombrows@lds.loral.com
Organization: LORAL Data Systems
References: <CpyEp3.8z6@massive.its.bldrdoc.gov>
Date: Wed, 18 May 1994 13:25:43 GMT
Lines: 24

In article 8z6@massive.its.bldrdoc.gov, davidson@its.bldrdoc.gov () writes:
> 
> I have just found an old anemometer to measure wind speed.  Ih has the 
> typical three cups and uses two magnets and a reed relay giving four pulses
> per revolution.  Outside of sticking it out a car window, does anyone know
> the ration of revolutions to wind speed?  Is it linear?   Do reed relay
> have contact bounce?    Thanks    Steve


I'm currently interfacing an old Heath kit anemometer to a 68HC11's pulse
accumulator input.  The Heath kit anemometer gives four pulses per revolution
using reed switches.  I run the reed switch signal though a Schmitt trigger
for buffering and have had no problems with bounce on the 68HC11's pulse
accumulator input.  I'm sure the pulse accumulator must have some debounce
circuitry in it.

I have a circuit cook book that has an anemometer circuit in it.  The
sensor is identical to the Heath kit's.  The design gives the slope equation
to convert pulses per second to MPH.  I don't have it here but I'll post
if I remember to dig it out.

Bd


