On Tuesday, June 14, 2022 at 12:40:03 PM UTC-7, lang...@fonz.dk wrote:
> tirsdag den 14. juni 2022 kl. 21.21.00 UTC+2 skrev Don Y:

> > Personally, if I saw some added value to rolling my own, I'd
> > opt for a "vintage" speedometer's pickup:
> >
> > <https://i.ebayimg.com/images/g/JkMAAOSws21iGSc9/s-l1600.jpg>
> >
> > transferring motion through a "cable-in-cable" to a "head
> > unit" that has been gutted. Mount a toothed gear on the end
> > of the cable shaft *in* the head unit and sense rotation optically
> > or variable reluctance. Quadrature detector if you want to
> > be able to note direction of movement for FINE sensitivity.
> how would that make any sense compared to the simple and ultra reliable reed and magnet?
>
> Rube Goldberg would be proud

Two advantages: it knows forward from reverse, and it has angular sensitivity to sub-one-revolution
movement. It also doesn't need an adjustment-type mount for the sensor, just
slap it around the axle and mount the wheel. There's nothing to prevent that kind
of axle-mount item from having a magnet and quadrature reed switches, of course; the speedometer-cable
is a bit of a hassle compared to a signal wire.

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.

On Tue, 14 Jun 2022 20:09:26 +0300, Dimiter_Popoff <dp@tgi-sci.com>
wrote:

>On 6/14/2022 18:57, Joe Gwinn wrote:
>> On Tue, 14 Jun 2022 18:51:21 +0300, 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.
>>>
>>
>> .<https://en.wikipedia.org/wiki/Variable_reluctance_sensor>
>>
>>
>> Joe Gwinn
>
>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").

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

Dimiter_Popoff <dp@tgi-sci.com> wrote in
news: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.
>
Most out there do not sense every spoke, but instead sense a metal
flag attached to one spoke and most use a hall effect sensor
transducer for that.

John Dope <always.look@message.header> wrote in
news:t8afpb$t21$6@dont-email.me:

> 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.
>

With a range of error. At least unless you are using militsry grade
hardware and getting military grade resolves logged.

Phones are slow at keeping up. Use one riding a bus and you can
watch the lags in real time.

Johnny loses the phone on a bus gps test! Ehhhh!

Record-setting gas prices every day.

Highest inflation rate since 1981 when Ronald Reagan entered office.

DecadentLinuxUserNumeroUno@decadence.org wrote:

> John Dope <always.look@message.header> wrote in
> news:t8afpb$t21$6@dont-email.me:
>
>> 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.
>>
>
> With a range of error. At least unless you are using militsry grade
> hardware and getting military grade resolves logged.
>
> Phones are slow at keeping up. Use one riding a bus and you can
> watch the lags in real time.
>
> Johnny loses the phone on a bus gps test! Ehhhh!
>

John Dope <always.look@message.header> wrote in news:t8b1a0$h8t$1
@dont-email.me:

>
> Record-setting gas prices every day.

You forgot to mention record setting profits for oil companies AND
for the local gas stations, as they all jumped onto Trump's jack the
price to make Biden look bad bandwagon. You ain't fooling anyone,
you retarded fucks.

> Highest inflation rate since 1981 when Ronald Reagan entered
office.
The fault also of the oil companies as the food prices, etc. all
have logistical ties to fuel prices via the transportation industry
that distributes the end products.

You dopey Republitard idiots always conveniently ignore the factors
driving inflation that besets a new administration, especially if the
other party of previous admin is a bunch of vindictive idiots not
caring about the nation as they take their jabs at the other party.

Another reason why the likes of Perry should never hold a public
office.

You could not be more stupid if you tried.

Record-setting gas prices every day.

Highest inflation rate since 1981 when Ronald Reagan entered
office.

The stock market is down to below when Joe Biden entered office.

Biden's approval rating is falling to new lows.

DecadentLinuxUserNumeroUno@decadence.org wrote:

> John Dope <always.look@message.header> wrote in news:t8b1a0$h8t$1
> @dont-email.me:
>
>>
>> Record-setting gas prices every day.
>
> You forgot to mention record setting profits for oil companies AND
> for the local gas stations, as they all jumped onto Trump's jack the
> price to make Biden look bad bandwagon. You ain't fooling anyone,
> you retarded fucks.
>
>> Highest inflation rate since 1981 when Ronald Reagan entered
> office.
>
> The fault also of the oil companies as the food prices, etc. all
> have logistical ties to fuel prices via the transportation industry
> that distributes the end products.
>
> You dopey Republitard idiots always conveniently ignore the factors
> driving inflation that besets a new administration, especially if the
> other party of previous admin is a bunch of vindictive idiots not
> caring about the nation as they take their jabs at the other party.
>
> Another reason why the likes of Perry should never hold a public
> office.
>
> You could not be more stupid if you tried.
>

On 6/14/2022 1:39 PM, whit3rd wrote:
> On Tuesday, June 14, 2022 at 12:40:03 PM UTC-7, lang...@fonz.dk wrote:
>> tirsdag den 14. juni 2022 kl. 21.21.00 UTC+2 skrev Don Y:
>
>>> Personally, if I saw some added value to rolling my own, I'd
>>> opt for a "vintage" speedometer's pickup:
>>>
>>> <https://i.ebayimg.com/images/g/JkMAAOSws21iGSc9/s-l1600.jpg>
>>>
>>> transferring motion through a "cable-in-cable" to a "head
>>> unit" that has been gutted. Mount a toothed gear on the end
>>> of the cable shaft *in* the head unit and sense rotation optically
>>> or variable reluctance. Quadrature detector if you want to
>>> be able to note direction of movement for FINE sensitivity.
>> how would that make any sense compared to the simple and ultra reliable reed and magnet?
>>
>> Rube Goldberg would be proud
>
> Two advantages: it knows forward from reverse, and it has angular sensitivity to sub-one-revolution
> movement. It also doesn't need an adjustment-type mount for the sensor, just
> slap it around the axle and mount the wheel. There's nothing to prevent that kind
> of axle-mount item from having a magnet and quadrature reed switches, of course; the speedometer-cable
> is a bit of a hassle compared to a signal wire.
>
> 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...)

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

On 06/14/2022 12:00 PM, Dimiter_Popoff wrote:
> 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?

Most of the time. The 14" studded tires I run in the winter have a
smaller rolling diameter than the 15" tires the speedometer is
calibrated for so it's off by about 5mph. For that reason I'm in the
habit of looking at the Nuvi speed rather than the speedometer.

In some weather conditions or when I'm driving at the base of a ridge
that blocks the southern sky the GPS is wildly inaccurate so much so it
is easy to detect when it's having issues.

I often carry a GPSr when I'm hiking (Garmin Etex 20). The terrain is
mountainous here so satellite coverage can be sketchy. Sometimes the
distance is radically off as is the maximum speed. Unless I just rolled
down a slope I'm probably not hitting 4.7 mph. I don't think the device
has the intelligence to discard obvious false data points.

I've got one of the step apps on the phone. It says it does not use the
GPS so it's working off the accelerometer data and it's surprisingly
accurate for the mileage particularly considering there was no setup for
the length of my stride.

On 06/14/2022 12:44 PM, Lasse Langwadt Christensen wrote:
> tirsdag den 14. juni 2022 kl. 20.00.52 UTC+2 skrev Dimiter Popoff:
>> 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
>>> <d...@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?
>
> a car speedometer is only required to be -0 to +10%
>

And for most Japanese motorcycles it is +10%. The conventional wisdom is
it's a liability thing. Since they can't control aftermarket tires they
overstate the speed. You get used to subtracting 5 mph from the reading.

On 06/14/2022 01:01 PM, Dimiter_Popoff wrote:
> On 6/14/2022 21:21, whit3rd wrote:
>> On Tuesday, June 14, 2022 at 8:51:30 AM UTC-7, 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.
>>> ...use a magnet placed somewhere on one
>>> of the wheels and some sensor, ... I
>>> imagine it sensing just the spokes, i.e. making some inductive sensor.
>>
>> A magnet secured to a spoke, and a reed switch, makes a durable
>> sensor, but
>> is somewhat clumsy. A sensor of the metal spoke is hard, because spokes
>> aren't all magnetic, there's stainless steels.
>
> Aaaah, the stainless steel is a game changer of course. Had not thought
> of that at all - though I know the spokes are not rusty (some at the end
> where they are tightened to the wheel but not all and not much). And it
> is not like they have not seen water, 1-2 months ago getting back
> after waiting for a torrential rain to subside I was nearly in submarine
> mode ...

Carbon fiber spokes would be a problem too. The LCD odometer on my
motorcycle is old and is only legible if the temperature is close to 90
F so I adapted a bike speedometer/odometer. I epoxied the magnet on the
rim near the tire bead and built a bracket for the sensor. It works
quite well and since I can program in the rolling diameter of the front
wheel it is very accurate.

On 06/14/2022 12:24 PM, 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.
>

They just worked until the core of the flexible shaft broke. If you were
lucky the strands didn't tear up the housing so you could buy a new
core, figure out how long it had to be, cut if off, and crimp on the
square drive end. If you were really lucky the transmission end of the
drive was above the lubricant level so you didn't have Type F fluid
running down your arm.

While I can get nostalgic for the good old days I'm not senile enough to
forget what a pain in the butt it was when things just didn't work.

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.

On Tuesday, June 14, 2022 at 2:36:47 PM UTC-4, lang...@fonz.dk wrote:
> tirsdag den 14. juni 2022 kl. 20.28.02 UTC+2 skrev Ricky:
> > On Tuesday, June 14, 2022 at 2:00:52 PM UTC-4, Dimiter Popoff wrote:
> > > 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
> > > > <d...@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?
> > "Close" is probably the best you can claim. Each 1 second update is a second old by the time you get it from the GPS. The accuracy can be there, but it depends on the constellation. With some xx feet of accuracy, each calculation can have errors that are significant if you are not moving fast. 30 mph is 44 fps, so 14 foot accuracy (what I'm seeing now and a typical value) is significant. GPS measurements are typically filtered. That's one reason why your car navigation can prompt you rather late sometimes (or early).. It is hard for a GPS to know what lane you are in, but can tell if you are on the parallel access road and not the main highway.
> >
> https://www.gps.gov/systems/gps/performance/accuracy/

"This measure must be combined with other factors outside the government's control, including satellite geometry, signal blockage, atmospheric conditions, and receiver design features/quality, to calculate a particular receiver's speed accuracy."

--

Rick C.

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

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

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* (?)

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>

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

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.

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..

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...

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

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.

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.

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