On Thursday, June 16, 2022 at 11:24:15 PM UTC-4, rbowman wrote:> On 06/16/2022 09:28 AM, Don wrote: > > In the Winter the paved road to a promontory called Lookout must be > > mostly dry. Although snowy patches here and there are OK and crunchy > > rime ice is OK; black ice is a show stopper. > It certainly is. I was riding a trail that was mostly clear and came to > a patch of smooth ice. I figured I could blow past it but physics > disagreed.You need at least one more wheel for that to work. -- Rick C. -++ Get 1,000 miles of free Supercharging -++ Tesla referral code - https://ts.la/richard11209
Spoke sensor for bicycle
Started by ●June 14, 2022
Reply by ●June 17, 20222022-06-17
Reply by ●June 17, 20222022-06-17
On 2022-06-14, Ricky <gnuarm.deletethisbit@gmail.com> wrote:> On Tuesday, June 14, 2022 at 1:16:34 PM UTC-4, John Doe wrote: >> Dimiter_Popoff <d...@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. > > People often talk about cell phones as if they had universal > coverage. That is true for 99.9% of where people spend their time. > But that 0.1% of the time, like biking in the woods, you are out of > cell phone range. So any solution needs to not depend on a cell phone > connection. If you can use the GPS in your phone without a cell > connection, great! But I haven't found such a program as yet. Maybe > I just haven't dug deep enough.Well it's GPS so it's less reliable in tall cities or deep ravines. but it doesn't need a cell signal. -- Jasen.
Reply by ●June 18, 20222022-06-18
On 2022-06-14, Dimiter_Popoff <dp@tgi-sci.com> wrote:> On 6/14/2022 21:21, whit3rd wrote: > > Putting the magnet underneath the tire is an idea. Of course I might > lose it if I have a flat and repair it on the road (you won't believe > how often I was getting a flat until I got my latest tires, they claim > to have some Kevlar and I had just one flat in a year or two (can't > remember if I got them last year or the year before, almost replacement > due now). But then I have a decent supply of coin magnets, too (say 1mm > thick/10mm diameter)...you could attach the magnet using a tube patch. I have some 5mm magnets that would fit in a Schrader valve cap. -- Jasen.
Reply by ●June 18, 20222022-06-18
On Friday, June 17, 2022 at 10:30:56 PM UTC-4, Jasen Betts wrote:> On 2022-06-14, Ricky <gnuarm.del...@gmail.com> wrote: > > On Tuesday, June 14, 2022 at 1:16:34 PM UTC-4, John Doe wrote: > >> Dimiter_Popoff <d...@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. > > > > People often talk about cell phones as if they had universal > > coverage. That is true for 99.9% of where people spend their time. > > But that 0.1% of the time, like biking in the woods, you are out of > > cell phone range. So any solution needs to not depend on a cell phone > > connection. If you can use the GPS in your phone without a cell > > connection, great! But I haven't found such a program as yet. Maybe > > I just haven't dug deep enough. > > Well it's GPS so it's less reliable in tall cities or deep ravines. > but it doesn't need a cell signal.I suppose that's true if you have an app that doesn't require a network connection. The few apps I've tried don't seem to do much without a cell signal. Then there's the problem of cell phones running for very long in continuous use without being recharged. A friend's phone would only last a few hours when running a GPS app in his car. -- Rick C. +-- Get 1,000 miles of free Supercharging +-- Tesla referral code - https://ts.la/richard11209
Reply by ●June 18, 20222022-06-18
On Friday, June 17, 2022 at 7:30:56 PM UTC-7, Jasen Betts wrote:> On 2022-06-14, Joe Gwinn <joeg...@comcast.net> wrote: > > On Tue, 14 Jun 2022 18:51:21 +0300, Dimiter_Popoff <d...@tgi-sci.com> > > wrote:> >>I am sure there are people with more experience making inductive > >>sensors than I have.> > .<https://en.wikipedia.org/wiki/Variable_reluctance_sensor> > > That requires a magnetic material, some spokes are almost > non-magnetic stainless steel. (only very weakly paramagnetic)So, sense a sprocket tooth instead, or clip a magnet onto a spoke and don't rely on the spoke material at all. Hardest problem with reluctance is the low-output-at-slow-speed problem (Wiegand wire being one solution already mentioned).
Reply by ●June 18, 20222022-06-18
On 2022-06-18, whit3rd <whit3rd@gmail.com> wrote:> On Friday, June 17, 2022 at 7:30:56 PM UTC-7, Jasen Betts wrote: >> On 2022-06-14, Joe Gwinn <joeg...@comcast.net> wrote: >> > On Tue, 14 Jun 2022 18:51:21 +0300, Dimiter_Popoff <d...@tgi-sci.com> >> > wrote: > >> >>I am sure there are people with more experience making inductive >> >>sensors than I have. > >> > .<https://en.wikipedia.org/wiki/Variable_reluctance_sensor> >> >> That requires a magnetic material, some spokes are almost >> non-magnetic stainless steel. (only very weakly paramagnetic) > > So, sense a sprocket tooth instead, or clip a magnet onto a spoke and don't > rely on the spoke material at all. Hardest problem with reluctance is the > low-output-at-slow-speed problem (Wiegand wire being one solution already mentioned).You can mitigate the amplitude problem somewhat by parallelling a capacitor, but that won't boost the voltage at low speed, it just puts a hard limit on the high-speed output. Wiegand needs to be re-magnetised to the opposite polarity to produce a pulse, but two magnets are probably not a deal breaker if one is acceptable. -- Jasen.
Reply by ●June 23, 20222022-06-23
On 15/06/2022 07:52, Jan Panteltje 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...Forty years or so ago I was doing some work for either Austin Rover or British Leyland, can't remember which world-leading high-quality British car manufacturer, there were so many. Anyway, a test car they used had something like that - an optical device looking at the road to accurately measure speed. IIRC it was very expensive. I have a feeling it was something to do with diffraction gratings and prisms. -- Cheers Clive
Reply by ●June 27, 20222022-06-27
Clive Arthur wrote:> On 15/06/2022 07:52, Jan Panteltje 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... > > Forty years or so ago I was doing some work for either Austin Rover or > British Leyland, can't remember which world-leading high-quality British > car manufacturer, there were so many. > > Anyway, a test car they used had something like that - an optical device > looking at the road to accurately measure speed. IIRC it was very > expensive. > > I have a feeling it was something to do with diffraction gratings and > prisms. >There's a fun effect that's sometimes used in sensors for things like paper handlers: if you shine a laser on a rough surface, the speckle pattern moves exactly twice as fast as the surface. This turns out to be a fairly deep consequence of the law of reflection. 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
Reply by ●June 27, 20222022-06-27
On Tuesday, June 14, 2022 at 11:51:30 AM UTC-4, 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. > > 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.You're talking about devices that sell on Aliexpress for $1.29. If you're a halfway serious cyclist, there are computers that measure cadence, pedal rotations per minute, again with a magnet attached to the pedals, in addition to the usual RPM/ speed and total distance. Looks like the reed relays have been abandoned in favor of hall effect or the giant magntoresistance technology, dunno which. The packages are way too flat to house a relay. The little magnets and their housing look unchanged from the reed relay days. Plotting the actual route has always been a big deal for road cyclists, so I imagine GPS is used for that in the high end units- but they still need magnets and sensors for cadence measurement, and probably a backup for wheel RPM. The so-called industrial designers look first at the kind of functionality and form the prospective users will most likely want, and only then hand the design off to nuts and bolts people capable of making a physical product. You'll be hard pressed to improve upon or innovate existing products.> > ====================================================== > Dimiter Popoff, TGI http://www.tgi-sci.com > ====================================================== > http://www.flickr.com/photos/didi_tgi/
Reply by ●July 11, 20222022-07-11
In article <t8d3mh$hc9$1@dont-email.me>, Dimiter_Popoff <dp@tgi-sci.com> wrote: <SNIP>> >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.Everybody uses a bike here, including elderly with a heart condition. In the Netherlands electric bikes are quite popular. They are bought by people to occasionally take a slope easier, or go slightly faster. They are eminently practical and handle as normal bikes with benefits. At least 10 % of new bikes sold are electric (probably more). Groetjes Albert -- "in our communism country Viet Nam, people are forced to be alive and in the western country like US, people are free to die from Covid 19 lol" duc ha albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
