Forums > MaxMSP

tracking a bicycle speed

May 19, 2007 | 3:24 pm

Hi.

Can someone help me figuring out wich sensor or device would be best
to track the (rotation) speed of a fixed bicycle? The speed data is
then suposed to control the triggering and speed of some movie clips
with Max/MSP/Jitter in osX, using some analogue to digital converter,
wich, by the way, I would apreciate some advices about.
I’ve worked with sensors before, like flex, light, pressure and
others, but none of these would be of any use for this project.

thanks

rd


May 19, 2007 | 3:46 pm

I’d look into a Hall effect sensor paired with a magnet or magnets.
You really need something hi-speed, and these should be quite accurate.
There was a cool project at the NYU ITP department that used that to
drive a persistence of vision LED display in the bike wheel spokes.

Peter McCulloch


May 19, 2007 | 5:04 pm


May 19, 2007 | 7:47 pm



jln
May 19, 2007 | 9:04 pm


May 20, 2007 | 1:24 am


May 20, 2007 | 12:44 pm


May 20, 2007 | 1:02 pm

You could try one of those old light sets that has a small generator
with a wheel that rubs against the tyre – as you cycle faster the
light gets brighter – so a simple a to d would get you a value you
could work with. (although you might have to check the voltage
doesn’t get to high and damage your a to d)

HTH

Nick


May 20, 2007 | 3:30 pm


May 20, 2007 | 7:42 pm

hello and thanks to everyone for the quick answers.

Julien, you were right. There is indeed a thread that started in
April 2006 called "Bicycle as a Max/MSP interactive controller ",
wich seems to have escaped my first searches.

The mouse hacking > hi object solution would of course be the
cheapest and easiest to execute, and I’ll certainly try it first, but
I’m guessing it won’t be as robust and effective as, probably, the
hall effect sensors plus magnets.

Has someone really tried with the mouse? Did it work?

rd


May 20, 2007 | 9:32 pm

i used it, but on old school roller skates. worked nicely. you will
have problem with mouse off screen but this can be handled. i used an
old mouse, not the optical one (maybe optical is better as no direct
contact is needed), it was a bit sensitive. all in all, a sensor type
setup will be more robust.
are the bike stationery?

On 5/20/07, bragatel rmd74 wrote:
>
>
> hello and thanks to everyone for the quick answers.
>
> Julien, you were right. There is indeed a thread that started in April 2006
> called "Bicycle as a Max/MSP interactive controller ", wich seems to have
> escaped my first searches.
>
> The mouse hacking > hi object solution would of course be the cheapest and
> easiest to execute, and I’ll certainly try it first, but I’m guessing it
> won’t be as robust and effective as, probably, the hall effect sensors plus
> magnets.
>
> Has someone really tried with the mouse? Did it work?
>
> rd
>
>


May 20, 2007 | 10:01 pm


May 20, 2007 | 10:22 pm

or use a camera looking at the pedals, analyse its image and measure
with Jitter the alternance of changes (e.g. luminance average level)
when the pedal is in front of the camera;
see Davina project of one of my student on

http://www.erg.be/erg/spip.php?article263#


Yves Bernard yb@imal.org
asbl iMAL vzw
30-34 Quai des Charbonnages
1080 Bruxelles/Brussel
tel 32 2 410 30 93

http://www.imal.org
http://www.erg.be/blogs/artNumeur

http://www.i-cult.be


May 20, 2007 | 10:25 pm

one more suggestion. may or may not be helpful to you.
i created a patch for a sound installation that used a stationary bicycle wheel to control the sounds based on the speed and direction of rotation of the wheel.
i did this by pointing a camera at the wheel and motion tracking a bright red reflector on the wheel.
it was quite effective and responsive and easy to setup.

if you want, i can dig up the old patch that i used for this and post it. however, i don’t think there was anything too brilliant about it, just color tracking in four quadrants. don’t think i used any cv objects either, just jitter.

-rob


May 21, 2007 | 8:02 am

Or attach in some way a rotary encoder to the wheel – this would solve the
"twisted wire" problem and be really easy to interface to max – just hack a
cheap midi controller that has a rotary encoder. You can then track the
speed of the rotation of the encoder in max easily. This is probably the
cheapest and simplest option?

Jonathan.

On 20/05/07, Yves Bernard wrote:
>
> or use a camera looking at the pedals, analyse its image and measure
> with Jitter the alternance of changes (e.g. luminance average level)
> when the pedal is in front of the camera;
> see Davina project of one of my student on
> http://www.erg.be/erg/spip.php?article263#
>
> –
> Yves Bernard yb@imal.org
> asbl iMAL vzw
> 30-34 Quai des Charbonnages
> 1080 Bruxelles/Brussel
> tel 32 2 410 30 93
>
> http://www.imal.org
> http://www.erg.be/blogs/artNumeur
> http://www.i-cult.be
>


Jonathan Green
0777 1680 497
jonathan@jg1983.co.uk


May 21, 2007 | 8:43 am

What about audio.

You should put something on your bycicle, touching the wheel rays,
producing a rithmic sound (a card for example).

You then analyze this sound…

Just an idea ;-)

All the best

Alessandro Fogar

2007/5/21, Jonathan Green :
> Or attach in some way a rotary encoder to the wheel – this would solve the
> "twisted wire" problem and be really easy to interface to max – just hack a
> cheap midi controller that has a rotary encoder. You can then track the
> speed of the rotation of the encoder in max easily. This is probably the
> cheapest and simplest option?
>
> Jonathan.
>
>
> On 20/05/07, Yves Bernard wrote:
> > or use a camera looking at the pedals, analyse its image and measure
> > with Jitter the alternance of changes (e.g. luminance average level)
> > when the pedal is in front of the camera;
> > see Davina project of one of my student on
> > http://www.erg.be/erg/spip.php?article263#
> >
> > –
> > Yves Bernard yb@imal.org
> > asbl iMAL vzw
> > 30-34 Quai des Charbonnages
> > 1080 Bruxelles/Brussel
> > tel 32 2 410 30 93
> >
> > http://www.imal.org
> > http://www.erg.be/blogs/artNumeur
> > http://www.i-cult.be
> >
>
>
>
> –
> Jonathan Green
> 0777 1680 497
> jonathan@jg1983.co.uk
>
>


Alessandro Fogar

http://www.fogar.it


May 21, 2007 | 9:12 am

In a similar project i used 1 ultra-cheap reed-switch and a few magnets, and measure the time interval between the magnet(s). very simple, very cheap and (at least for my project) very useful.

http://images.google.com/images?svnum=10&hl=nl&gbv=2&q=reed+switch

Jeroen.


May 21, 2007 | 9:56 am

Jeroen Groot skrev:
> In a similar project i used 1 ultra-cheap reed-switch and a few magnets, and measure the time interval between the magnet(s). very simple, very cheap and (at least for my project) very useful.
>
> http://images.google.com/images?svnum=10&hl=nl&gbv=2&q=reed+switch
Very nice! I didn’t know about reed switches until now. Great product!
To me this looks like a winner.

Andreas.


May 21, 2007 | 11:20 pm

Peter McCulloch schrieb:
> I’d look into a Hall effect sensor paired with a magnet or magnets. You
> really need something hi-speed, and these should be quite accurate.
> There was a cool project at the NYU ITP department that used that to
> drive a persistence of vision LED display in the bike wheel spokes.

I would hack one of these cheap tachometers, they use hall sensors, some
of them are even wireless….

Stefan


Stefan Tiedje————x——-
–_____———–|————–
–(_|_ —-|—–|—–()——-
– _|_)—-|—–()————–
———-()——–www.ccmix.com



VG
May 22, 2007 | 9:04 am


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