On Sun, 12 May 2019 06:27:51 -0700, sms
wrote:

On 5/12/2019 1:29 AM, Tosspot wrote:
Anyone know of some 'decent' ones.* The Sigma supplied ones won't
attract a whore in a crack house.* The Bosch type ones always seem to
corrode and fall off, and on top of that are easy to X-Thread.* The
Cat-Eye ones don't seem to stay put[1].* The Echowell/Yamaha ones seem
pretty decent but are like rocking horse **** this side of the pond. Any
other ideas?

[1] Yes, it is getting OCD!

When I lost the cadence magnet on my crank I used a hard-drive magnet,
i.e. https://www.ebay.com/itm/173209158372 but I got some used ones
from someone I knew at a disk drive company. I heat shrinked it over the
crank. I guess for a wheel magnet you could use some cable ties or some
baling wire and attach one of these to the spokes. The pick-up doesn't
have to be so close to the magnet when you use a disk drive magnet.

I tried a disk drive magnet and had problems. The typical magnet is
not a single piece of iron with a single pair of poles, but rather two
magnets with two pairs of poles:
https://physics.stackexchange.com/questions/12283/if-you-place-a-spring-on-a-neodymium-hard-drive-magnet-it-appears-to-vibrate-in
By adjusting the position and orientation, it worked quite well.
However, if the magnet moved, I would get erratic operation. I got my
best resuls by breaking a magnet in half, resulting in (mostly) one
pair of poles. I don't recall which brand of bicycle computah I used,
but I think it may have been a Sigma.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558