Spoke sensor for bicycle

On 6/15/2022 9:24 AM, Don wrote:
> 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.

GPS-based "distance traveled" figures tend to overestimate the
actual distance traveled.  Even a beginner is taught to always
reference measurements from a common point (instead of stacking
measurement errors).

On a sunny day (Wed, 15 Jun 2022 11:45:56 -0400) it happened Joe Gwinn
<joegwinn@comcast.net> wrote in <dhvjahhi98bc6se5ft4rmphtc0co0kbq8b@4ax.com>:

>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?

Concrete is not that 'featureless' at all.
As to the software, if you look up any open source mpegX encoding (X for 1, 2, whatever have you these days)
you will see it, among other things,  calculates a motion vector, remember using that long long time ago...
Given fixed frames per second (30 or 25 depending on where you are), lens angle and hight,
calibration would only take a short time.
I use my puter mice on a white table and it never had a problem.
Maybe shine a light or laser down to the ground.
Its just a possible solution, not saying its better than other ones, but fun for experimenting.



>Or if it's raining or snowing?

I do not go biking in weather like  that, I look at the rain-rader here first for what's coming.

On 6/15/2022 12:29, Clive Arthur wrote:
> 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&nbsp; "at DC").
> 
> A former colleague used a clever method for an impeller type flow 
> sensor.&nbsp; He used a small unshielded inductor with a parallel capacitor 
> connected to a PIC pin.&nbsp; Set the pin to be an output, kick the LC with a 
> pulse, then set the pin to be an input and count oscillations.&nbsp; In air, 
> you get a few counts, near metal, you get fewer counts.&nbsp; 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.
> 

The method is neat indeed. I think I could make that work, I'd say a 3mm
maximum distance from the spokes is achievable mechanically. Hmm. Might
not give up the idea yet after all. Especially after trying out so far
3 apps for the phone, each useless for one reason or another.

On Wednesday, 15 June 2022 at 18:39:57 UTC+2, Don Y wrote:
> On 6/15/2022 9:24 AM, Don wrote: 
> > 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.
> GPS-based "distance traveled" figures tend to overestimate the 
> actual distance traveled. Even a beginner is taught to always 
> reference measurements from a common point (instead of stacking 
> measurement errors).
you are not correct

you can easily switch GPS receiver in your smartphone into exact RTK GPS mode to get 20 cm accuracy

so bike computer is an ancient stuff, no more hot

On Wednesday, 15 June 2022 at 18:44:04 UTC+2, Jan Panteltje wrote:
> On a sunny day (Wed, 15 Jun 2022 11:45:56 -0400) it happened Joe Gwinn 
> <joeg...@comcast.net> wrote in <dhvjahhi98bc6se5f...@4ax.com>:
> >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?
> Concrete is not that 'featureless' at all. 
> As to the software, if you look up any open source mpegX encoding (X for 1, 2, whatever have you these days) 
> you will see it, among other things, calculates a motion vector, remember using that long long time ago... 
> Given fixed frames per second (30 or 25 depending on where you are), lens angle and hight, 
> calibration would only take a short time. 
> I use my puter mice on a white table and it never had a problem. 
> Maybe shine a light or laser down to the ground. 
> Its just a possible solution, not saying its better than other ones, but fun for experimenting.
> >Or if it's raining or snowing?
> I do not go biking in weather like that, I look at the rain-rader here first for what's coming.
excellent
laser/optical mouse can be easily turned into $10 3D LIDAR scanner

On 6/15/2022 9:02, Don Y wrote:
>......
> 
> 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).

I manage to carry a 5-6 kg backpack biking from the nearby (4-5 km)
shops. And the way back is uphill (not dramatic though). If it is
reasonably flat in your area you will just need a backpack similar
to mine - Lucy gave it to me when I got the bike, she had used it
years ago when she was walking up the mountains. Very light but
strong enough.

> 
> 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?&nbsp; <grin> >

I have seen "normal" bicycles with a battery and some electric
motor... I was told the motor just helps you, they are made not
to move on their own, you have to pedal but you get assistance
(making life easier uphill I suppose). Some nonsense that, why
would I bike if I didn't want the exercise.

On 6/15/2022 10:01 AM, a a wrote:
> On Wednesday, 15 June 2022 at 18:39:57 UTC+2, Don Y wrote:
>> On 6/15/2022 9:24 AM, Don wrote:
>>> 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.
>> GPS-based "distance traveled" figures tend to overestimate the
>> actual distance traveled. Even a beginner is taught to always
>> reference measurements from a common point (instead of stacking
>> measurement errors).
> you are not correct
> 
> you can easily switch GPS receiver in your smartphone into exact RTK GPS mode to get 20 cm accuracy

So, I can move  8 inches to the left of where I am and your app will tell me
that I've (1) moved, (2) which direction I've moved, (3) that it was 8 inches?

Wow, so you can RELY on having a good constellation available to you,
at all times, in all places?  What world do YOU live in?

<https://www.dcrainmaker.com/2011/12/why-new-york-times-gps-running-article.html>

<https://spectrum.ieee.org/why_every_gps_overestimates_distance_traveled>

<http://gpsinformation.net/articles/tripdistanceerror.htm>

And, of course, your statement applies to ALL smartphones, right?

> so bike computer is an ancient stuff, no more hot

Joe Gwinn wrote:
> 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
> 

Trying to keep any optical surface clean enough is a challenge.   A 
theremin would be a fun way to do it, if not necessarily the most practical.

Cheers

Phil Hobbs

On Wednesday, 15 June 2022 at 19:08:41 UTC+2, Dimiter Popoff wrote:
> On 6/15/2022 9:02, Don Y wrote: 
> >......
> > 
> > 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).
> I manage to carry a 5-6 kg backpack biking from the nearby (4-5 km) 
> shops. And the way back is uphill (not dramatic though). If it is 
> reasonably flat in your area you will just need a backpack similar 
> to mine - Lucy gave it to me when I got the bike, she had used it 
> years ago when she was walking up the mountains. Very light but 
> strong enough.
> > 
> > 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> >
> I have seen "normal" bicycles with a battery and some electric 
> motor... I was told the motor just helps you, they are made not 
> to move on their own, you have to pedal but you get assistance 
> (making life easier uphill I suppose). Some nonsense that, why 
> would I bike if I didn't want the exercise.
by global legislation
you can't turn your bike into scooter

Joerg wrote:
> On 6/14/22 10:16 AM, John Doe wrote:
>> 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. 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.
>>
>> This might be blasphemy, but...
>>
>> Speed and mileage indication is easily done with a smartphone these days,
>> at least here in America.
>>
> 
> Then, later in the afternoon during an all-day ride, there will be a low 
> battery warning, followed by a dark screen.
> 
> Why do we always have to make things so complicated? When I grew up 
> speedometers didn't even need any electrical power. They just worked.
> 

And then pissed transmission oil on your pant cuffs when the oil seal 
failed. ;)

Plus the nanny software didn't prevent one from putting the top down 
while rolling, even turning round in the driveway. :(

I really wish there were a "nanny disable" button next to the one for 
traction control.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com