wrote:
On Saturday, July 29, 2017 at 6:20:47 PM UTC-7, John B. wrote:
On Sat, 29 Jul 2017 14:48:23 -0700, Joerg
wrote:

On 2017-07-29 13:46, Graham wrote:

"Joerg" wrote in message
...
On 2017-07-29 12:16, wrote:
On Saturday, July 29, 2017 at 7:06:59 AM UTC-7, Joerg wrote:
On 2017-07-29 02:14, Graham wrote:

"Joerg" wrote in message
...
Had to change the battery again on my Bell Dashboard 100
cycling speedometer. Or what they call "cycle computer" In
the manual it says one can re-enter the odometer reading
but nowhere it says how. When I contacted Bell years ago
they said "no, you can't". Does anyone know a secret trick
Bell doesn't know?

I keep a log but it gets old having to calculate to see
when the rear tire or other stuff is nearing end-of-life.
Mainly to avoid a *KAPOW* surprise way out in the boonies.
Many tires don't have TWI.

-- Regards, Joerg

http://www.analogconsultants.com/

Looking at your day job from the above link why not just
design a circuit to replicate the job of the magnet which is
only a switch which is creating a pulsed current/voltage read
by the head unit electronics. Then set the tyre size to
maximum and determine the maximum response frequency of the
head unit circuitry and simulate pulses at that frequency. If
the frequency is reasonably high it should not take too long
to reset the mileage. With a tyre circumference of 9999mm, if
it will take that, then you are looking at 10m per Hz.


Sure I could design a meter that works better than commercial
one. However, I've got enough electronics projects as it is.
When I am fully retired, maybe. But then I want to ride instead
of build replacements for messed-up commercial designs. On the
bikes I already had to do that for lighting but there it was a
necessity.

If I ever build my own it will be like what cars have since
over 100 years. A speedometer that is backlit at night, works
off the central battery and most of all never forgets its
odometer info.

I think that he was suggesting that you pulse the meter until it
reaches the mileage you originally had.


Yes, I misunderstood Graham. If almost all brands contain Reed
switches like Andrew said that might not be so great for the
lifetime of that switch. Also, it would eat up battery because
there will be a limit in the speed and I guess that's not the same
at on a Ferrari Testarossa. So I'd have to let that artificial
wheel run a long time in order to get the usual 4000+ miles back
in, and next time 8000+, then 12000+ and so on. Most likely that
takes weeks.

-- Regards, Joerg

http://www.analogconsultants.com/

It looks like you still have not got it. Lets forget the grinder idea
as I agree with Andrew about the read switches and that does tend to
rule that idea out. My first idea was to do it electronically with a
simple circuit that would send relatively high frequency pulses to
the appropriate terminals on the head unit to simulate the action of
the switch. From your decription of your background surely this is a
trivial exercise and I am sure you will have the required circuit
components lying around on your bench. See my earlier posts as to how
long it would take at different frquency pulsing if you set the tyre
circumference to 9999mm. 4000 miles would take around 180 hours at
1Hz, 18 hours at 10Hz etc and my guess is that the head unit circuit
should at least cope with that. Any higher frequecy response would be
a bonus.


Yeah, I could hack the cable aoart, roach on a MOSFET, wrap the whole
enchilade with duct take and feed pulses from a function generator :-)

I think in that case the better alternative would be to buy a better
designed meter like the one I have on the MTB (Cateye Padrone) that does
allow odometer re-entry.

I only started this thread to see if someone knows a trick. There is a
discrepancy between the Bell manual and what Bell's customer service
says. The manual explicitly says you should write down the odometer
value before a battery change and then re-enter it after installing a
new battery. Their customer service said that it cannot be done. So one
of them is wrong.

Early on in this thread you mentioned that you "kept a log". If so why
can't you simply add the previous mileage to the present (post battery
change) reading of your bike meter to get total mileage?

I have an annual log application that I wrote and that is what I do.
Simply enter the last year's total at the top of the new log and the
computer shows the current "lifetime total".

That wouldn't work with me because with the medication I would forget to do it.


That's one of the advantages of using Garmin (or similar) with Strava (or
similar) in that it just happens no or little interaction needed, and then
it logs for you mileage of various bike parts.

It's a handy little tool really, I mostly use it since I like the mapping.

Roger Merriman