[Spridgets] New Smiths 130 MPH 3.5" Speedo, $50

[David Lieb]

>       i see some of the sigma bicycle computers are even wireless!!!! 
> which
>       model(s) do you use/recommend?..

I use the BC1200, but I believe it has been discontinued. I do not recommend 
the wireless, since there is a significant amount of groundplane between 
source and reader. I tried several different mountings to read the wheel 
rpm. First attempt was inside the brake drum, but it did not account for the 
amount of lateral motion of the hub and did not read consistently in corners 
and curves. The second attempt went to reading the driveshaft rotation at 
the diff. Nice consistent readings, but the pulses per second were too high 
for the computed functions... speed readout was perfect, but odo readings 
did not increment properly when you were over 60mph or so. When a 750 mile 
drive registerd as 400 miles, I figured I ought to correct something. 
Fortunately, the trip gave me plenty of time to figure out what might be 
causing it... I ended up using JB Weld to attach the magnet to the rear 
brake drum and mounting the reed switch on a metal strap attached to the 
backing plate. Works good.
I am told that dollhouse wiring works well for extending the distance.
David Lieb