Spoke sensor for bicycle...

[Ricky]

On Tuesday, June 14, 2022 at 3:04:05 PM UTC-4, whit3rd wrote:

On Tuesday, June 14, 2022 at 11:32:03 AM UTC-7, Ricky wrote:
On Tuesday, June 14, 2022 at 2:21:58 PM UTC-4, whit3rd wrote:
... a reluctance
sensor on a gear-cluster tooth? There\'s some DC insensitivity, unlike with Hall
sensors, but maybe a low-speed signal dropout isn\'t going to be a bother.

Does it have to be magnetic? A conductor moving in a magnetic field creates a current which also creates a magnetic field which can be detected, no?
A nonmagnetic gear tooth will (in motion) disturb a magnetic field, and make a pulse.
The eddy current response, though, is less than a ferromagnetic material\'s, and has a time decay
of its own, added to the coil\'s DC insensitivity.

An IR (modulated? polarized?) source, aimed at a retroreflector on a spoke, has good range and sensitivity, at a cost
of some power usage. Rejecting ambient light and dirt are other issues there.

I know they use induced currents in aluminum cans to separate them using a magnet. The magnet spins under the conveyor belt making the cans jump off the end, while the rest of the stream simply falls off. A friend who worked in the industry complained that my crushing cans made this not work as well. But my cans are sold as aluminum, not mixed into the all-in-one stream..

--

Rick C.

--- Get 1,000 miles of free Supercharging
--- Tesla referral code - https://ts.la/richard11209

 

[Don Y]

On 6/14/2022 6:07 PM, whit3rd wrote:

On Tuesday, June 14, 2022 at 5:22:18 PM UTC-7, Don Y wrote:
On 6/14/2022 1:39 PM, whit3rd wrote:

A better solution would be to instument a hub and axle, but the axle diameter is fixed by the bicycle frame, and
the hub by the wheel-builders. That means redesigns of the mechanical bits unless one lucks out and
finds a compatible generator hub off-the-shelf.

The biggest win is it gets you away from the wheel. E.g., you could affix a
bar magnet to the end of the cable-in-cable and detect it\'s rotation (to
whatever extent you desire) as well as using its motion to generate *power*
for the circuit (esp with the ultra low power technologies now available;
think about the tire-rubbing generators that used to power headlamps...)

Yeah; those delivered 2 or 3 watts; enough for a halogen flashlight lamp,
and to charge a 6V lead/acid battery for standstill lighting.

I\'ve not seen one in decades. They seem to predate the \"10 speed\" time in
my life.

But, I recall them as putting lots of drag on the wheel. And, as a
\"rotation sensor\", they would be inadequate as I doubt the signal
would \"integrate\" well.

If you use
one built into a wheel hub, the dynamo pole count determines the AC cycles per mile travelled.

OK. That would be similar to my \"spinning magnet\" idea.

The friction type can be precalibrated easily (the drive drum circumference is better known
than the tire\'s) if it engages the tread rather than the sidewall of the tire.

I don\'t think the output would translate into \"revolutions\" well, across the
range of possible speeds. Likewise, I imagine it would still produce an
output when the wheel moved *backwards* (?)

 

[Don Y]

On 6/14/2022 7:03 PM, rbowman wrote:

On 06/14/2022 06:22 PM, Don Y wrote:
The biggest win is it gets you away from the wheel. E.g., you could
affix a
bar magnet to the end of the cable-in-cable and detect it\'s rotation (to
whatever extent you desire) as well as using its motion to generate *power*
for the circuit (esp with the ultra low power technologies now available;
think about the tire-rubbing generators that used to power headlamps...)

What a wondrous invention they were... All that aggro for a one candlepower
headlamp. Somehow I associate those with the Sturmey-Archer three speed hubs.

I suppose driving a generator that way is better than driving the bicycle with
a 26cc motor in a similar way:

http://bumblebeebolton.com/front_instructions.html

I thought the concept might have been relegated to the trash bin of history but
I\'ve seen a similar design for a DIY low rent eBike.

I\'ve been looking for an \"alternate\" form of transportation for the
little jaunts -- to the library, post office, etc. Just a couple of
miles, likely off-road.

Things like bicycle, Segway, one-wheels, etc. come to mind. But, none
have really checked all the boxes (e.g., carrying a bag of groceries
on a bike or Segway is really not ideal).

But, recently, I\'m liking the idea of a small gas powered generator
tucked in the battery compartment of my electric wheelchair (!).
This would eliminate the maintenance issue of the batteries
($400/set) as well as increase the possible RELIABLE range of
the chair. (of course, you couldn\'t use it indoors but that\'s fine)

Building on that idea, a gas powered Segway? <grin>

 

[Clifford Heath]

On 15/6/22 16:02, Don Y wrote:

On 6/14/2022 7:03 PM, rbowman wrote:
On 06/14/2022 06:22 PM, Don Y wrote:
The biggest win is it gets you away from the wheel.  E.g., you could
affix a
bar magnet to the end of the cable-in-cable and detect it\'s rotation (to
whatever extent you desire) as well as using its motion to generate
*power*
for the circuit (esp with the ultra low power technologies now
available;
think about the tire-rubbing generators that used to power headlamps...)

What a wondrous invention they were... All that aggro for a one
candlepower headlamp. Somehow I associate those with the
Sturmey-Archer three speed hubs.

I suppose driving a generator that way is better than driving the
bicycle with a 26cc motor in a similar way:

http://bumblebeebolton.com/front_instructions.html

I thought the concept might have been relegated to the trash bin of
history but I\'ve seen a similar design for a DIY low rent eBike.

I\'ve been looking for an \"alternate\" form of transportation for the
little jaunts -- to the library, post office, etc.  Just a couple of
miles, likely off-road.

Things like bicycle, Segway, one-wheels, etc. come to mind.  But, none
have really checked all the boxes (e.g., carrying a bag of groceries
on a bike or Segway is really not ideal).

Cargo bike? Or trike? Possibly electric?

But, recently, I\'m liking the idea of a small gas powered generator
tucked in the battery compartment of my electric wheelchair (!).
This would eliminate the maintenance issue of the batteries
($400/set) as well as increase the possible RELIABLE range of
the chair.  (of course, you couldn\'t use it indoors but that\'s fine)

Building on that idea, a gas powered Segway?  <grin

You could carry a genset on a cargo bike.

Ch

 

[Jan Panteltje]

On a sunny day (Tue, 14 Jun 2022 21:00:44 +0300) it happened Dimiter_Popoff
<dp@tgi-sci.com> wrote in <t8aicd$2uq$1@dont-email.me>:

On 6/14/2022 20:43, Jan Panteltje wrote:
On a sunny day (Tue, 14 Jun 2022 18:51:21 +0300) it happened Dimiter_Popoff
dp@tgi-sci.com> wrote in <t8aapr$ab6$1@dont-email.me>:

I started cycling again (used to as a kid...) some 4 years ago.
And while I know there are plenty of super cheap \"bicycle computers\"
I have been thinking of making my own.
Thus so far 4 years no speed/mileage indicator for me, obviously.
While this may likely remain the case forever I am still thinking
about it - not the obvious things like the MCU, display etc., just
the rotation sensor. They all use a magnet placed somewhere on one
of the wheels and some sensor, I have used a Hall sensor for
pretty precise positioning of the rotor of our TLD reader etc.,
but I only still keep on thinking of making the thing because I
imagine it sensing just the spokes, i.e. making some inductive sensor.

I know what I will try out etc., I may even get to designing one before
the millennium is over but well, these thoughts seem to be on topic and
I am sure there are people with more experience making inductive
sensors than I have.

Or you could make something like my gm_pic2:
http://panteltje.com/panteltje/pic/gm_pic2/

It uses GPS and writes to SDcard or EEPROM where you were at any time, logs radiation there too
There is software to replay the trip on google maps.
After all the GPS talk here ..
Simple maaz using the space and time between data points will allow you to find speed and distances.
A GPS module and a Microchip 18F14k22 + EEPROM is all you need.
Oh and a battery...
Now been working 24/7 for 8 years... As clock mostly.
No tinkering with your bike needed.
Also logs trips per bus or train.



Is the GPS accuracy/latency of the speed measurement close to that of
a car\'s speed indicator?

You will have to average here and there I suppose.
Seems reasonabale to me, but have not tried on a bike.
Latency is very low.

 

[Jan Panteltje]

On a sunny day (Tue, 14 Jun 2022 22:01:01 +0300) it happened Dimiter_Popoff
<dp@tgi-sci.com> wrote in <t8altd$uqm$1@dont-email.me>:

The Hall sensors I have \"in the drawer\" are some with hysteresis though,
they need such a magnet really close (within 1mm if not less) to work,
would need some other kind but that should be the easiest part.
But well, it looks I am not going to start the project any time soon.
And I did download some biking app to the phone, this makes the
project\'s prospects even more bleak...

An other way would be a laser diode shining through the spikes and a photocell picking it up on the other side.
Be careful not to burn out eyes of some kids.
The acceleration sensor would work nice too,
some code is on my site that uses a 6 axis accelerometer but not for speed.. math seems easy enough though.
Did I not write code for a navigation system using only such accelerometers, yes,
needed an oven, some uni redid the experiment .. its on Usenet..

 

[Jan Panteltje]

On a sunny day (Tue, 14 Jun 2022 17:56:50 -0400) it happened Joe Gwinn
<joegwinn@comcast.net> wrote in <4a0iahhpmhi9ocv7ig0k1nidjn95mqbbg1@4ax.com>:

Well, there is also Wiegand-wire sensors:

.<https://en.wikipedia.org/wiki/Wiegand_effect

.<https://en.wikipedia.org/wiki/Wiegand_Sensor

But as others have noted, the spokes may be non-magnetic. This can be
solved by adding a bit of zinc-plated mild steel tubing (automotive
brake line) glued to at least one spoke with a silicon rubber
adhesive. The spoke would pass through an inch of tube, with silicon
rubber filling the gap between tube and spoke.

Joe Gwinn

Just thinking, use a camera looking down
The speed can be derived from the moving pattern it sees
Almost like a computah mouse...

 

[Clive Arthur]

On 14/06/2022 18:09, Dimiter_Popoff wrote:

<snipped>

Hmmm, but will that work at really low speed (like when pushing the
bike uphill)? It is an idea to do it this way (I did not even know the
name of the method so the idea is more than welcome), yet what I was
thinking was more in the line of changing some oscillation frequency
(thus detecting the spokes also  \"at DC\").

A former colleague used a clever method for an impeller type flow
sensor. He used a small unshielded inductor with a parallel capacitor
connected to a PIC pin. Set the pin to be an output, kick the LC with a
pulse, then set the pin to be an input and count oscillations. In air,
you get a few counts, near metal, you get fewer counts. I don\'t know
details, but he was able to sample sufficiently quickly for it to work.

My guess is that it wouldn\'t be practical over the clearance distance
you\'d need for a spoke, but it\'s a neat method.

--
Cheers
Clive

 

[rbowman]

On 06/15/2022 12:02 AM, Don Y wrote:

Things like bicycle, Segway, one-wheels, etc. come to mind. But, none
have really checked all the boxes (e.g., carrying a bag of groceries
on a bike or Segway is really not ideal).

There are quite a few cargo bikes or if you already have a bike,
trailers. A friend has a BOB Yak that worked out well. It\'s easy to
disconnect if you don\'t need it and the single wheel means it tracks on
the same path as the bike if you ride single track.

The low cost solution would be looking for one of those child trailers
at a yard sale.

There are also bike panniers but you wind up repacking the groceries to
get everything to fit. Two wheeled grocery shopping on either a bicycle
or motorcycle tends to limit impulse purchases.

 

[Ricky]

On Wednesday, June 15, 2022 at 2:56:59 AM UTC-4, Jan Panteltje wrote:

On a sunny day (Tue, 14 Jun 2022 22:01:01 +0300) it happened Dimiter_Popoff
d...@tgi-sci.com> wrote in <t8altd$uqm$1...@dont-email.me>:
The Hall sensors I have \"in the drawer\" are some with hysteresis though,
they need such a magnet really close (within 1mm if not less) to work,
would need some other kind but that should be the easiest part.
But well, it looks I am not going to start the project any time soon.
And I did download some biking app to the phone, this makes the
project\'s prospects even more bleak...

An other way would be a laser diode shining through the spikes and a photocell picking it up on the other side.
Be careful not to burn out eyes of some kids.
The acceleration sensor would work nice too,
some code is on my site that uses a 6 axis accelerometer but not for speed.. math seems easy enough though.
Did I not write code for a navigation system using only such accelerometers, yes,
needed an oven, some uni redid the experiment .. its on Usenet..

Optics get dirty and stop working. They also are impacted by precipitation.. No one wants an intermittent speed-o-meter.

I think the clear winner in this contest is the playing car against the spokes.

Actually, I think people have trivialized away the variable reluctance sensor. While the spoke may not be magnetic, it\'s no trouble adding a small piece of metal to the spoke or spoke nipple or even the hub. I believe spokes on most bikes are arranged to cross and form an X. The crossing point may be a good place to put the metal badge.

--

Rick C.

--+ Get 1,000 miles of free Supercharging
--+ Tesla referral code - https://ts.la/richard11209

 

[bob prohaska]

Dimiter_Popoff <dp@tgi-sci.com> wrote:

I started cycling again (used to as a kid...) some 4 years ago.
And while I know there are plenty of super cheap \"bicycle computers\"
I have been thinking of making my own.

Can any of the commercially available bicycle odometer/speedometers
use the output from a hub dynamo for measuring distance/speed? The
Shimano DH3N72 gives, I think, 14 cycles per turn. Using a diode to
half-wave rectify it would make 7 pulses per turn.

Thanks for reading,

bob prohaska

Thus so far 4 years no speed/mileage indicator for me, obviously.
While this may likely remain the case forever I am still thinking
about it - not the obvious things like the MCU, display etc., just
the rotation sensor. They all use a magnet placed somewhere on one
of the wheels and some sensor, I have used a Hall sensor for
pretty precise positioning of the rotor of our TLD reader etc.,
but I only still keep on thinking of making the thing because I
imagine it sensing just the spokes, i.e. making some inductive sensor.

I know what I will try out etc., I may even get to designing one before
the millennium is over but well, these thoughts seem to be on topic and
I am sure there are people with more experience making inductive
sensors than I have.


======================================================
Dimiter Popoff, TGI http://www.tgi-sci.com
======================================================
http://www.flickr.com/photos/didi_tgi/

 

[Joe Gwinn]

On Wed, 15 Jun 2022 06:52:43 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Tue, 14 Jun 2022 17:56:50 -0400) it happened Joe Gwinn
joegwinn@comcast.net> wrote in <4a0iahhpmhi9ocv7ig0k1nidjn95mqbbg1@4ax.com>:

Well, there is also Wiegand-wire sensors:

.<https://en.wikipedia.org/wiki/Wiegand_effect

.<https://en.wikipedia.org/wiki/Wiegand_Sensor

But as others have noted, the spokes may be non-magnetic. This can be
solved by adding a bit of zinc-plated mild steel tubing (automotive
brake line) glued to at least one spoke with a silicon rubber
adhesive. The spoke would pass through an inch of tube, with silicon
rubber filling the gap between tube and spoke.

Joe Gwinn

Just thinking, use a camera looking down
The speed can be derived from the moving pattern it sees
Almost like a computah mouse...

Need to also block the view beyond those spokes, or nearby scenery can
affect speed readings.

Joe Gwinn

 

[Don Y]

On 6/15/2022 6:50 AM, rbowman wrote:

On 06/15/2022 12:02 AM, Don Y wrote:
Things like bicycle, Segway, one-wheels, etc. come to mind. But, none
have really checked all the boxes (e.g., carrying a bag of groceries
on a bike or Segway is really not ideal).

There are quite a few cargo bikes or if you already have a bike, trailers. A
friend has a BOB Yak that worked out well. It\'s easy to disconnect if you don\'t
need it and the single wheel means it tracks on the same path as the bike if
you ride single track.

Bikes won\'t work well as I\'d want to be able to take the \"shortcuts\"
over dirt/gravel/grass. Something more \"ATV-ish\" is called for.
Hence the Segway option. (The Segway \"egg\" looks do-able)

[I can save half a mile on the trip to the library using \"walkable\"
shortcuts]

I also have to be wary of the laws regarding where you can operate
said \"conveyance\". E.g., I don\'t think bicycles are allowed on sidewalks.
And, the rules for ebikes might be different.

OTOH, the wheelchair probably squeaks through the legalities in the
most permissive ways. (and, I don\'t think there is anything that
says the rider must NEED the wheelchair... just like the driver of
a vehicle with disabled plates needn\'t be disabled!)

The gas-powered genset might run afoul of \"something\", though...

The low cost solution would be looking for one of those child trailers at a
yard sale.

There are also bike panniers but you wind up repacking the groceries to get
everything to fit. Two wheeled grocery shopping on either a bicycle or
motorcycle tends to limit impulse purchases.

Years ago, I tried the bike approach. Driving on the roads is just too
perilous. Having to cross 4 lanes of 45+MPH traffic several times on each
\"short trip\" left my nerves jangled.

 

[Joe Gwinn]

On Tue, 14 Jun 2022 20:03:12 -0600, rbowman <bowman@montana.com>
wrote:

On 06/14/2022 06:22 PM, Don Y wrote:
The biggest win is it gets you away from the wheel. E.g., you could
affix a
bar magnet to the end of the cable-in-cable and detect it\'s rotation (to
whatever extent you desire) as well as using its motion to generate *power*
for the circuit (esp with the ultra low power technologies now available;
think about the tire-rubbing generators that used to power headlamps...)

What a wondrous invention they were... All that aggro for a one
candlepower headlamp.

I had one of those generators as well. The drag from that generator
was quite significant. And I could see better by ambient (street
lamp) light. I went to using an ordinary flashlight to warn cars of
my presence.

Somehow I associate those with the Sturmey-Archer
three speed hubs.

A blast from the past. I got very good at adjusting and repairing
them.

It took me a year to figure out why, when pedaling strongly the foot
crank would abruptly come loose, free-rotate a half-turn or so, and
then reconnect, as if nothing had happened.

It turned out that the bronze C-ring that expanded against the inside
of the hub to brake the wheel had become worn enough to allow the four
drive pins to pull out of their sockets under heavy load, rotate
sliding un till managing to drop back into the same sockets, clocked
but undamaged. Replacing the C-ring solved the problem.

Sturmey-Archer still exists, and has all the old documentation online.

..<http://www.sturmey-archerheritage.com/index.php?page=history&type=technic&era=1>

I suppose driving a generator that way is better than driving the
bicycle with a 26cc motor in a similar way:

http://bumblebeebolton.com/front_instructions.html

I thought the concept might have been relegated to the trash bin of
history but I\'ve seen a similar design for a DIY low rent eBike.

I recall similar things from the 1960s as well. Was never tempted. I
bet they sounded like an infuriated bumblebee, only higher pitched.
And LOUD.

Joe Gwinn

 

[Joe Gwinn]

On Wed, 15 Jun 2022 06:52:43 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Tue, 14 Jun 2022 17:56:50 -0400) it happened Joe Gwinn
joegwinn@comcast.net> wrote in <4a0iahhpmhi9ocv7ig0k1nidjn95mqbbg1@4ax.com>:

Well, there is also Wiegand-wire sensors:

.<https://en.wikipedia.org/wiki/Wiegand_effect

.<https://en.wikipedia.org/wiki/Wiegand_Sensor

But as others have noted, the spokes may be non-magnetic. This can be
solved by adding a bit of zinc-plated mild steel tubing (automotive
brake line) glued to at least one spoke with a silicon rubber
adhesive. The spoke would pass through an inch of tube, with silicon
rubber filling the gap between tube and spoke.

Joe Gwinn

Just thinking, use a camera looking down
The speed can be derived from the moving pattern it sees
Almost like a computah mouse...

Second answer: Ignore spokes. Looking down at the street surface
flying by? How does this work on featureless concrete or tarred
blacktop? Or a painted surface?

Or if it\'s raining or snowing?

Joe Gwinn

 

[Don]

Joerg wrote:

Dimiter_Popoff wrote:
I started cycling again (used to as a kid...) some 4 years ago.
And while I know there are plenty of super cheap \"bicycle computers\"
I have been thinking of making my own.
Thus so far 4 years no speed/mileage indicator for me, obviously.
While this may likely remain the case forever I am still thinking
about it - not the obvious things like the MCU, display etc., just
the rotation sensor. They all use a magnet placed somewhere on one
of the wheels and some sensor, I have used a Hall sensor for
pretty precise positioning of the rotor of our TLD reader etc.,
but I only still keep on thinking of making the thing because I
imagine it sensing just the spokes, i.e. making some inductive sensor.


There are at least two reasons for the magnet. One is that it triggers a
reed contact on the other side. This allows the whole speedometer to not
have to be turned off by hand for battery conservation. It simply does
that on its own and when the reed switch changes state again it turns
itself back on. So you can just park your bike and walk away. Well,
maybe not in a large city because then it gets stolen.

The second reason is that this system works down to very low speeds.
There isn\'t actually a lower limit and it will still clock the miles
correctly.


I know what I will try out etc., I may even get to designing one before
the millennium is over but well, these thoughts seem to be on topic and
I am sure there are people with more experience making inductive
sensors than I have.


I can already smell an engineer\'s solution coming up. Huge sensor,
multiple bus cables, a laptop mounted to the handlebar ...

My own mountain cycling takes place year around. Throughout the winter:

<https://crcomp.net/arts/spintale/winter.png>

as well as the summer:

<https://crcomp.net/arts/spintale/summer.png>

Here\'s a inverted perspective image of the outcrop show by the second
picture. It\'s taken from the road\'s point-of-view. The outcrop is the
smaller of the two shown. It appears to the left of the larger outcrop,
on the left summit. The photo gives you an idea of the mountain trail\'s
inaccessibility:

<https://crcomp.net/arts/spintale/invert.png>

My MP3 mod makes spins so much more enjoyable these days:

<https://crcomp.net/mp3mod/index.php>

Anyhow, long story short, a cadence sensor would theoretically work
better than a speedometer, for me personally. And a GPS solution
probably can\'t cadence count accurately.

As others already more-or-less mentioned, the industry tends to utilize
spoke magnets:

<https://heavy.com/sports/top-best-speed-cadence-sensors-bike-garmin-edge-zwift-computer/>

The frames of some bicycles accommodate optional bolt-on sensors:

<https://www.dcrainmaker.com/2011/02/look-at-trekbontrager-frame-integrated.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Don]

Addendum: My own links need to be read by me /before/ they\'re posted. It
seems GPS sensors replaced magnets.

Joerg wrote:

Dimiter_Popoff wrote:
I started cycling again (used to as a kid...) some 4 years ago.
And while I know there are plenty of super cheap \"bicycle computers\"
I have been thinking of making my own.
Thus so far 4 years no speed/mileage indicator for me, obviously.
While this may likely remain the case forever I am still thinking
about it - not the obvious things like the MCU, display etc., just
the rotation sensor. They all use a magnet placed somewhere on one
of the wheels and some sensor, I have used a Hall sensor for
pretty precise positioning of the rotor of our TLD reader etc.,
but I only still keep on thinking of making the thing because I
imagine it sensing just the spokes, i.e. making some inductive sensor.


There are at least two reasons for the magnet. One is that it triggers a
reed contact on the other side. This allows the whole speedometer to not
have to be turned off by hand for battery conservation. It simply does
that on its own and when the reed switch changes state again it turns
itself back on. So you can just park your bike and walk away. Well,
maybe not in a large city because then it gets stolen.

The second reason is that this system works down to very low speeds.
There isn\'t actually a lower limit and it will still clock the miles
correctly.


I know what I will try out etc., I may even get to designing one before
the millennium is over but well, these thoughts seem to be on topic and
I am sure there are people with more experience making inductive
sensors than I have.


I can already smell an engineer\'s solution coming up. Huge sensor,
multiple bus cables, a laptop mounted to the handlebar ...

My own mountain cycling takes place year around. Throughout the winter:

<https://crcomp.net/arts/spintale/winter.png>

as well as the summer:

<https://crcomp.net/arts/spintale/summer.png>

Here\'s a inverted perspective image of the outcrop show by the second
picture. It\'s taken from the road\'s point-of-view. The outcrop is the
smaller of the two shown. It appears to the left of the larger outcrop,
on the left summit. The photo gives you an idea of the mountain trail\'s
inaccessibility:

<https://crcomp.net/arts/spintale/invert.png>

My MP3 mod makes spins so much more enjoyable these days:

<https://crcomp.net/mp3mod/index.php>

Anyhow, long story short, here\'s 15 sensors:

<https://heavy.com/sports/top-best-speed-cadence-sensors-bike-garmin-edge-zwift-computer/>

The frames of some bicycles accommodate optional bolt-on sensors:

<https://www.dcrainmaker.com/2011/02/look-at-trekbontrager-frame-integrated.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Ricky]

On Wednesday, June 15, 2022 at 11:46:09 AM UTC-4, Joe Gwinn wrote:

On Wed, 15 Jun 2022 06:52:43 GMT, Jan Panteltje
pNaonSt...@yahoo.com> wrote:
On a sunny day (Tue, 14 Jun 2022 17:56:50 -0400) it happened Joe Gwinn
joeg...@comcast.net> wrote in <4a0iahhpmhi9ocv7i...@4ax.com>:

Well, there is also Wiegand-wire sensors:

.<https://en.wikipedia.org/wiki/Wiegand_effect

.<https://en.wikipedia.org/wiki/Wiegand_Sensor

But as others have noted, the spokes may be non-magnetic. This can be
solved by adding a bit of zinc-plated mild steel tubing (automotive
brake line) glued to at least one spoke with a silicon rubber
adhesive. The spoke would pass through an inch of tube, with silicon
rubber filling the gap between tube and spoke.

Joe Gwinn

Just thinking, use a camera looking down
The speed can be derived from the moving pattern it sees
Almost like a computah mouse...
Second answer: Ignore spokes. Looking down at the street surface
flying by? How does this work on featureless concrete or tarred
blacktop? Or a painted surface?

Or if it\'s raining or snowing?

I once had a mouse that would work on glass! Images have a lot more information than you might think. Nothing is completely uniform.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

[a a]

On Wednesday, 15 June 2022 at 18:05:04 UTC+2, Ricky wrote:

On Wednesday, June 15, 2022 at 11:46:09 AM UTC-4, Joe Gwinn wrote:
On Wed, 15 Jun 2022 06:52:43 GMT, Jan Panteltje
pNaonSt...@yahoo.com> wrote:
On a sunny day (Tue, 14 Jun 2022 17:56:50 -0400) it happened Joe Gwinn
joeg...@comcast.net> wrote in <4a0iahhpmhi9ocv7i...@4ax.com>:

Well, there is also Wiegand-wire sensors:

.<https://en.wikipedia.org/wiki/Wiegand_effect

.<https://en.wikipedia.org/wiki/Wiegand_Sensor

But as others have noted, the spokes may be non-magnetic. This can be
solved by adding a bit of zinc-plated mild steel tubing (automotive
brake line) glued to at least one spoke with a silicon rubber
adhesive. The spoke would pass through an inch of tube, with silicon
rubber filling the gap between tube and spoke.

Joe Gwinn

Just thinking, use a camera looking down
The speed can be derived from the moving pattern it sees
Almost like a computah mouse...
Second answer: Ignore spokes. Looking down at the street surface
flying by? How does this work on featureless concrete or tarred
blacktop? Or a painted surface?

Or if it\'s raining or snowing?
I once had a mouse that would work on glass! Images have a lot more information than you might think. Nothing is completely uniform.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209
optical/laser mouse as movement sensor or local LIDAR is still a hot item, loved by developers.

GPS smartphones replaced old bike computers 10-15 years ago
and there is no return

 

[Don]

Addendum: My own links need to be read by me /before/ they\'re posted. It
seems GPS sensors replaced magnets.

Addendum 2: It\'s unknown what role, if any, GPS plays with bicycle
cadence/speedometer sensors. May your own Inet search discover reality,
as my own Inet searches for quick answers are now a thing of the past.

Joerg wrote:

Dimiter_Popoff wrote:
I started cycling again (used to as a kid...) some 4 years ago.
And while I know there are plenty of super cheap \"bicycle computers\"
I have been thinking of making my own.
Thus so far 4 years no speed/mileage indicator for me, obviously.
While this may likely remain the case forever I am still thinking
about it - not the obvious things like the MCU, display etc., just
the rotation sensor. They all use a magnet placed somewhere on one
of the wheels and some sensor, I have used a Hall sensor for
pretty precise positioning of the rotor of our TLD reader etc.,
but I only still keep on thinking of making the thing because I
imagine it sensing just the spokes, i.e. making some inductive sensor.


There are at least two reasons for the magnet. One is that it triggers a
reed contact on the other side. This allows the whole speedometer to not
have to be turned off by hand for battery conservation. It simply does
that on its own and when the reed switch changes state again it turns
itself back on. So you can just park your bike and walk away. Well,
maybe not in a large city because then it gets stolen.

The second reason is that this system works down to very low speeds.
There isn\'t actually a lower limit and it will still clock the miles
correctly.


I know what I will try out etc., I may even get to designing one before
the millennium is over but well, these thoughts seem to be on topic and
I am sure there are people with more experience making inductive
sensors than I have.


I can already smell an engineer\'s solution coming up. Huge sensor,
multiple bus cables, a laptop mounted to the handlebar ...

My own mountain cycling takes place year around. Throughout the winter:

<https://crcomp.net/arts/spintale/winter.png>

as well as the summer:

<https://crcomp.net/arts/spintale/summer.png>

Here\'s a inverted perspective image of the outcrop show by the second
picture. It\'s taken from the road\'s point-of-view. The outcrop is the
smaller of the two shown. It appears to the left of the larger outcrop,
on the left summit. The photo gives you an idea of the mountain trail\'s
inaccessibility:

<https://crcomp.net/arts/spintale/invert.png>

My MP3 mod makes spins so much more enjoyable these days:

<https://crcomp.net/mp3mod/index.php>

Anyhow, long story short, FWIW, here\'s a 15 sensors link returned on the
first page of an Inet search:

<https://heavy.com/sports/top-best-speed-cadence-sensors-bike-garmin-edge-zwift-computer/>

The frames of some bicycles accommodate optional bolt-on sensors:

<https://www.dcrainmaker.com/2011/02/look-at-trekbontrager-frame-integrated.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.