To get it calibrated you might be able to take advantage of the tripset on
the unit. Set the circumference to an approximate value then take the car
out on a measured course (around here we have sections of highway with a
stretch that has signs indicating the actual distance traveled from point to
point). Drive for a measured mile then compared the distance reading on
your tripset. Adjust your circumference setting up or down based on whether
your tripset reading was higher or lower than the correct distance traveled.
Repeat the process until you get as accurate as possible.
Let's say you set the circumference to 50 inches to start out. Assume at
the end of the mile your tripset reads .9 mile instead of the correct 1
mile. This means your reading is low so change your circumference to 55.5
inches (50/.9 not 50*1.1).
Graham
68 1600
----- Original Message -----
From: Dan Neuman <dneuman@stars.sfsu.edu>
To: <VulForge@aol.com>; <datsun-roadsters@autox.team.net>
Sent: Thursday, June 15, 2000 2:31 AM
Subject: Re: Bike speedometers in the roadster
> Hi Russ,
> I think the driveshaft is the best idea. I just need to figure out how
> to mount the sensor... Hmmmm the driveshaft will move through an angle
> as the rear end moves over bumps... maybe if I put the magnet on the
output
> shaft of the transmission. Then I still have to figure out a way to mount
the
> sender within ~5mm. Oh, a trick a lot of MC guys use is to go to radio
shack
> abd buy the strongest rare earth magnet possible, this will give a better
> signal and allow a slightly sloppier alignment. Another drawback is, is
that it
> will probably take two people to do the circumfrence measurement-one to
> watch the wheel and one to watch the drive shaft-since you need to know
how
> far forward the car went in one revolution of the drive shaft...maybe I
can
> get this done this weekend.
> Daniel 69 2000\
>
> At 11:29 PM -0400 6/14/00, VulForge@aol.com wrote:
> >In a message dated 6/14/00 6:39:59 PM Central Daylight Time,
> >dneuman@stars.sfsu.edu writes:
> >
> ><< Now I jsut gotta find a place to mount it. The tolerances between the
> > magnet and the sender are very small. ~5mm. I need to mount it
somewhere
> > where that can happen and somewhere that will not get very hot. Any
> > suggestions?? >>
> >
> >How about the driveshaft? That would be the shortest possible point, and
the
> >circumference won't vary. Of course it will read high when you spin the
> >tires!
> >
> >Russ
> >67 1600
>
>
>
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