On 7/29/2017 4:48 PM, 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.


Or more probably the actual manufacturer may be totally
random based on being Bell's low bidder from time to time.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971