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Bell Dashboard 100, re-enter odo numbers?



 
 
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  #11  
Old July 29th 17, 07:09 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Bell Dashboard 100, re-enter odo numbers?

On 2017-07-29 10:44, AMuzi wrote:
On 7/29/2017 11:34 AM, Joerg wrote:
On 2017-07-29 09:16, AMuzi wrote:
On 7/29/2017 10:19 AM, Graham wrote:

"Joerg" wrote in message
...
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.
[snip]

No you miss my point. I am not suggesting you
design/build a new unit
simply knock up a simple circuit to mimic the magnet
driven switch
opening and closing and connect it to the appropriate
terminals on the
head unit. If the unit can respond to switching rates up
to say 1kHz
then the job should be reasonably quick and could be left
to run for a
known period of time to get the mileage back to where you
want it. At
10m per switch cycle you would advance the reading
36kms/hr at 1hz so
100Hz which should be possible would give you 3600kms/hr
1KHz would
look to be ideal as it would give you 36,000kms/hr.

A bench grinder would also work with a magnet fixed to it
and the
sensor held next to it. That might take a good bit longer
depending on
the speed of the grinder.


Ah, yes, clocking it all back in by pretending a 4120mi
ride. Good idea. I could take an old printer motor, mout a
wooden disc, glue a little magent on that and strap the
whole thing into the spokes.

It would probably take days though since the speedometer
will peg somewhere. And eat a lot of the new battery's juice
which would kind of defeat the purpose.


There are sensors which can read 1720~1760rpm (grinder
speeds) but a
copper-steel reed switch is not one of them.


Reed switches would be way too expensive for such products.
It's usually just a coil. Almost has to be because it must
generate a voltage that triggers the turned-off meter
circuitry to turn on upon wheel rotation.


Except for rare exceptions (ex: defunct Avocet), almost all bicycle
computers use that type of switch to iterate wheel or crank rpm.


Interesting, I didn't know that. I develop similar stuff for industrial
purposes such position and rotation sensors. I'd never use Reed or
anything mechanical in those, especially in an environment that is prone
to vibration. Like ... a mountain bike.

--
Regards, Joerg

http://www.analogconsultants.com/
Ads
  #12  
Old July 29th 17, 08:16 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,345
Default Bell Dashboard 100, re-enter odo numbers?

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.
  #13  
Old July 29th 17, 08:18 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,345
Default Bell Dashboard 100, re-enter odo numbers?

On Saturday, July 29, 2017 at 9:34:42 AM UTC-7, Joerg wrote:
On 2017-07-29 09:16, AMuzi wrote:
On 7/29/2017 10:19 AM, Graham wrote:

"Joerg" wrote in message
...
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.
[snip]

No you miss my point. I am not suggesting you design/build a new unit
simply knock up a simple circuit to mimic the magnet driven switch
opening and closing and connect it to the appropriate terminals on the
head unit. If the unit can respond to switching rates up to say 1kHz
then the job should be reasonably quick and could be left to run for a
known period of time to get the mileage back to where you want it. At
10m per switch cycle you would advance the reading 36kms/hr at 1hz so
100Hz which should be possible would give you 3600kms/hr 1KHz would
look to be ideal as it would give you 36,000kms/hr.

A bench grinder would also work with a magnet fixed to it and the
sensor held next to it. That might take a good bit longer depending on
the speed of the grinder.



Ah, yes, clocking it all back in by pretending a 4120mi ride. Good idea.
I could take an old printer motor, mout a wooden disc, glue a little
magent on that and strap the whole thing into the spokes.

It would probably take days though since the speedometer will peg
somewhere. And eat a lot of the new battery's juice which would kind of
defeat the purpose.


There are sensors which can read 1720~1760rpm (grinder speeds) but a
copper-steel reed switch is not one of them.


Reed switches would be way too expensive for such products. It's usually
just a coil. Almost has to be because it must generate a voltage that
triggers the turned-off meter circuitry to turn on upon wheel rotation.


No, it has to be a switch because a coil would have ****-poor battery life.
  #14  
Old July 29th 17, 08:31 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Bell Dashboard 100, re-enter odo numbers?

On 2017-07-29 12:18, wrote:
On Saturday, July 29, 2017 at 9:34:42 AM UTC-7, Joerg wrote:
On 2017-07-29 09:16, AMuzi wrote:
On 7/29/2017 10:19 AM, Graham wrote:

"Joerg" wrote in message
...
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.
[snip]

No you miss my point. I am not suggesting you design/build a new unit
simply knock up a simple circuit to mimic the magnet driven switch
opening and closing and connect it to the appropriate terminals on the
head unit. If the unit can respond to switching rates up to say 1kHz
then the job should be reasonably quick and could be left to run for a
known period of time to get the mileage back to where you want it. At
10m per switch cycle you would advance the reading 36kms/hr at 1hz so
100Hz which should be possible would give you 3600kms/hr 1KHz would
look to be ideal as it would give you 36,000kms/hr.

A bench grinder would also work with a magnet fixed to it and the
sensor held next to it. That might take a good bit longer depending on
the speed of the grinder.


Ah, yes, clocking it all back in by pretending a 4120mi ride. Good idea.
I could take an old printer motor, mout a wooden disc, glue a little
magent on that and strap the whole thing into the spokes.

It would probably take days though since the speedometer will peg
somewhere. And eat a lot of the new battery's juice which would kind of
defeat the purpose.


There are sensors which can read 1720~1760rpm (grinder speeds) but a
copper-steel reed switch is not one of them.


Reed switches would be way too expensive for such products. It's usually
just a coil. Almost has to be because it must generate a voltage that
triggers the turned-off meter circuitry to turn on upon wheel rotation.


No, it has to be a switch because a coil would have ****-poor battery life.


Not if it's designed right and the impulse triggers a dormant circuit
which then starts the whole speedometer. A pre-bias to narrow the
threshold could be done with less than a micro-ampere. The downside is
that is doesn't work at extremely slow wheel rotation but nobody really
needs that.

--
Regards, Joerg

http://www.analogconsultants.com/
  #15  
Old July 29th 17, 08:35 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Bell Dashboard 100, re-enter odo numbers?

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/
  #16  
Old July 29th 17, 09:46 PM posted to rec.bicycles.tech
Graham
external usenet poster
 
Posts: 206
Default Bell Dashboard 100, re-enter odo numbers?


"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.

Graham.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

  #17  
Old July 29th 17, 10:48 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Bell Dashboard 100, re-enter odo numbers?

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.

--
Regards, Joerg

http://www.analogconsultants.com/
  #18  
Old July 30th 17, 02:01 AM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 5,870
Default Bell Dashboard 100, re-enter odo numbers?

On Saturday, July 29, 2017 at 10:44:08 AM UTC-7, AMuzi wrote:
On 7/29/2017 11:34 AM, Joerg wrote:
On 2017-07-29 09:16, AMuzi wrote:
On 7/29/2017 10:19 AM, Graham wrote:

"Joerg" wrote in message
...
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.
[snip]

No you miss my point. I am not suggesting you
design/build a new unit
simply knock up a simple circuit to mimic the magnet
driven switch
opening and closing and connect it to the appropriate
terminals on the
head unit. If the unit can respond to switching rates up
to say 1kHz
then the job should be reasonably quick and could be left
to run for a
known period of time to get the mileage back to where you
want it. At
10m per switch cycle you would advance the reading
36kms/hr at 1hz so
100Hz which should be possible would give you 3600kms/hr
1KHz would
look to be ideal as it would give you 36,000kms/hr.

A bench grinder would also work with a magnet fixed to it
and the
sensor held next to it. That might take a good bit longer
depending on
the speed of the grinder.


Ah, yes, clocking it all back in by pretending a 4120mi
ride. Good idea. I could take an old printer motor, mout a
wooden disc, glue a little magent on that and strap the
whole thing into the spokes.

It would probably take days though since the speedometer
will peg somewhere. And eat a lot of the new battery's juice
which would kind of defeat the purpose.


There are sensors which can read 1720~1760rpm (grinder
speeds) but a
copper-steel reed switch is not one of them.


Reed switches would be way too expensive for such products.
It's usually just a coil. Almost has to be because it must
generate a voltage that triggers the turned-off meter
circuitry to turn on upon wheel rotation.


Except for rare exceptions (ex: defunct Avocet), almost all
bicycle computers use that type of switch to iterate wheel
or crank rpm.


I could sell him my old Avocet, and he could kludge it.

It seems to me like he could get a sharpie and write on the screen "+ [number of miles]." Problem solved. Or maybe put the number in his wallet on the back of a growler fill coupon -- or tattoo it to his forehead. Or, plan B, just look at his tires to see if they are worn -- or measure his chain. I suppose this would impede the completion of his definitive work on tire and chain wear rates by brand and model, but only for one wear cycle. A new chain or tire would have a new odometer reading. I don't think tires wear any faster if a bike has more or less cumulative miles, but I could be wrong about that. I had some high mile bikes that would just blow through tires.

-- Jay Beattie.



  #19  
Old July 30th 17, 02:20 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default Bell Dashboard 100, re-enter odo numbers?

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".
--
Cheers,

John B.

  #20  
Old July 30th 17, 02:38 AM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,345
Default Bell Dashboard 100, re-enter odo numbers?

On Saturday, July 29, 2017 at 12:31:13 PM UTC-7, Joerg wrote:
On 2017-07-29 12:18, wrote:
On Saturday, July 29, 2017 at 9:34:42 AM UTC-7, Joerg wrote:
On 2017-07-29 09:16, AMuzi wrote:
On 7/29/2017 10:19 AM, Graham wrote:

"Joerg" wrote in message
...
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.
[snip]

No you miss my point. I am not suggesting you design/build a new unit
simply knock up a simple circuit to mimic the magnet driven switch
opening and closing and connect it to the appropriate terminals on the
head unit. If the unit can respond to switching rates up to say 1kHz
then the job should be reasonably quick and could be left to run for a
known period of time to get the mileage back to where you want it. At
10m per switch cycle you would advance the reading 36kms/hr at 1hz so
100Hz which should be possible would give you 3600kms/hr 1KHz would
look to be ideal as it would give you 36,000kms/hr.

A bench grinder would also work with a magnet fixed to it and the
sensor held next to it. That might take a good bit longer depending on
the speed of the grinder.


Ah, yes, clocking it all back in by pretending a 4120mi ride. Good idea.
I could take an old printer motor, mout a wooden disc, glue a little
magent on that and strap the whole thing into the spokes.

It would probably take days though since the speedometer will peg
somewhere. And eat a lot of the new battery's juice which would kind of
defeat the purpose.


There are sensors which can read 1720~1760rpm (grinder speeds) but a
copper-steel reed switch is not one of them.


Reed switches would be way too expensive for such products. It's usually
just a coil. Almost has to be because it must generate a voltage that
triggers the turned-off meter circuitry to turn on upon wheel rotation..


No, it has to be a switch because a coil would have ****-poor battery life.


Not if it's designed right and the impulse triggers a dormant circuit
which then starts the whole speedometer. A pre-bias to narrow the
threshold could be done with less than a micro-ampere. The downside is
that is doesn't work at extremely slow wheel rotation but nobody really
needs that.


That does sound correct but that would mean that if you placed a magnet a little too far away from the detector, that it would have a stronger field with an increase in speed. So it would report speed at higher speed but not at lower. And that doesn't appear to be the case with any of my dozen or so speedos that I've used in the last five years. Usually you have to have the magnet almost touching the detector and at higher speeds a slightly too large a distance will cause the speedo to stop registering.

For such a simple device they sure are a pain in the butt.
 




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