Re: Question: How to make a counter/timer using PC mouse input

From: Kitchen Man (nannerbac_at_yahoo.com)
Date: 02/27/05 

Date: Sun, 27 Feb 2005 16:52:05 -0700

On Sun, 27 Feb 2005 00:03:39 -0600 in sci.electronics.basics, Randy Day
<ruthal@sasktel.nex> wrote msg <1122oo72qghioa6@corp.supernews.com>:

>irving@outgun.com wrote:
>> I would like to count the number of wheel revolutions of my indoor bike
>> during training indoors, and don't know anything about electronics.
>> I've taken apart an old, $2.99 mouse from an older PC and was able to
>> "read" when the mouse buttons were clicked using javascript. I'd like
>> to use that concept to make a bicycle wheel counter and write a
>> javascript to keep track of speed. Any suggestions on how I'd do it?
>
>If the bike wheel has spokes, mount a
>lever-action microswitch on the fork so
>that it depresses when a spoke goes
>by. Wire the switch in parallel with
>your mouse button.

That's going to be a tremendous amount of wear on the switch, there will
be dozens of mechanical actions for each revolution. This type of
operation would be implemented much more reliably with a magnet on the
rim and a stationary hall-effect sensor. There are already many such
devices available on the marketplace (bikenashbar.com for one), and the
inputs from the device could be wired in parallel to the mouse input, as
well as the original equipment. That would give a double-check that the
numbers are accurate. 

-- 
Al Brennan
http://www.xmission.com/~tiger885/motorbike/NART/nart.html
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