Measuring Bicycle Speed
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Posts: 46,084
Why not try an rc circuit to ADC and use pulse from magnet to read voltage
then discharge capacitor.
Murray
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 7:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
then discharge capacitor.
Murray
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 7:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
Comments
of a bicycle. The wheels would be turning in the 60 to 600rpm range
which is too slow to use the pulsin. I could use multiple magnets on
the wheel but I would really like to avoid that. I thought I could
use the LM2907(freq to voltage converter) followed by an ADC but I
found the low frequency produced too much ripple. Based on time I
would need about a .001sec resolution. The easy to use clock chips
seem to have only 1sec resolution. Any suggestions on how I could
solve this problem?
engine to the bike and read the velocity output from the serial output of
the GPS receiver, thus not having to worry about pulse measurement. It
depends on your budget. also, don't forget the Stamp has little memory so to
log speed would require that the data is dumped to another device to ensure
data is not lost.
Good luck!
Original Message
From: Murray Snowden [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Na7Myy062COjc_4l1y5-_pJ1u2xnP330xnf49olRS7EXMJ6aldJc639tpgEqxhohi4guHjgdrTY8uoZK]mursnow@m...[/url
Sent: Friday, May 26, 2000 8:21 AM
To: basicstamps@egroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
Why not try an rc circuit to ADC and use pulse from magnet to read voltage
then discharge capacitor.
Murray
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 7:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
Only update/refresh the mph display when there is a valid number(not 0)
returned.
Haven't done the math on this.....but if the two magnets are very close this
will give you a faster response. Of course you would have to have some
electronics with this prior to the stamp......flip-flop?
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 5:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
>
Another thought: You might be able to press a PAK-VII into service. With the
prescaler you can measure some long pulses at lower resolution or short
pulses at higher resolutions. http://www.al-williams.com/awce/pak7.htm.
Regards,
Al Williams
AWC
*New: 8 channel pulse output for servos, PWM, etc.
http://www.al-williams.com/awce/pak8.htm
>
Original Message
> From: jimsp@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ONC3YW99jmnSchDm8C4WZsaOdycwb_TUyZTv7nKiJJmtfc_0ssv0lvxSyVrk4gQjdcD4UdGJQSw33w]jimsp@y...[/url
> Sent: Friday, May 26, 2000 7:36 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
>
>
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
Use one of those generators used for head lights on bicycles. Measure the
dc output, a little calibration and you got it. As a bonus the generator
could power the BS2 or at least recharge battery.
Mike.
Original Message
From: jimsp@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=9cKO6OKzkLOoWdeC2b9P9NufbbqJ2W7sgIX-118NA8nUZc5GVGg3czSsQU-GvU3oxZ8AtqI]jimsp@y...[/url
Sent: Friday, May 26, 2000 5:36 AM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
I'm trying to use the BS2 to measure and periodically log the speed
of a bicycle. The wheels would be turning in the 60 to 600rpm range
which is too slow to use the pulsin. I could use multiple magnets on
the wheel but I would really like to avoid that. I thought I could
use the LM2907(freq to voltage converter) followed by an ADC but I
found the low frequency produced too much ripple. Based on time I
would need about a .001sec resolution. The easy to use clock chips
seem to have only 1sec resolution. Any suggestions on how I could
solve this problem?
> ....................I could use multiple magnets on
> the wheel but I would really like to avoid that.
(snip)
What is your objection to magnets? Balance?
I don't think small magnets, spaced evenly would
cause a problem at the speed you mention, but as
an alternative, how about optical sensing of white/
black stripes painted on the rim? This shouldn't
cause any balance problem, but may not work if
you're a mudder.
--Stu
>which is too slow to use the pulsin...... Based on time I
>would need about a .001sec resolution. The easy to use clock chips
>seem to have only 1sec resolution. Any suggestions on how I could
>solve this problem?
A programmed timer loop?
x var word
input 1 ' active low, capacitor debounced
top: x=0
wait: if in1 then wait ' await switch closed
time0: x=x+1: branch in1,[noparse][[/noparse]time0] ' count & await switch open
time1: x=x+1: if in1 then time1 ' count await switch closed
other:
' calculate and log--
here: branch in1,[noparse][[/noparse]here,top] ' await switch open
The resolution will be on the order of one millisecond. Once calibrated, it
should be well within your accuracy requirements.
Other timer chips you may not have considered are described at:
Steve Parkis' site
http://home.earthlink.net/~parkiss/tm1summ.txt
Peter Anderson's site
http://www.phanderson.com/timer_1_2.html
I hope that helps
-- Tracy Allen
Electronically Monitored Ecosystems
http://www.emesystems.com
computer for $20-$30. Gives you speed, distance, avg. speed, max speed.
etc. Check out www.nashbar.com.
Stew Benedict
On Fri, 26 May 2000, Witherspoon, Michael J wrote:
> Or mabey...
>
> Use one of those generators used for head lights on bicycles. Measure the
> dc output, a little calibration and you got it. As a bonus the generator
> could power the BS2 or at least recharge battery.
>
>
> Mike.
>
>
>
>
Original Message
> From: jimsp@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ujYEke0QTZkww_h9B_9T7ajFX_Mj23ZancR5934HxXrQFRr0XvH6047M73s_D-_GeBot4RJKIw]jimsp@y...[/url
> Sent: Friday, May 26, 2000 5:36 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
>
>
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
>
>
>
>
>
jimsp@y... wrote:
>
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
connect 1 magnet to a wheel with a hall effect sensor.
Connect an oscillator to a binary counter (couple hundred Hz) and the hall
effect sensor to the stamp.
When the wheel goes around it will pulse the stamp which will read the
counter then reset it. The longer it takes the wheel to go around the
higher the counter gets. Some simple math after that.
The smack shack rare earth magnets work with a jameco hall effect sensor.
This worked until I got pics :-)
Mike
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 8:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
>
have a switching speed of 800 hz
LarryGaminde wrote:
>
> use the count command
>
> jimsp@y... wrote:
> >
> > I'm trying to use the BS2 to measure and periodically log the speed
> > of a bicycle. The wheels would be turning in the 60 to 600rpm range
> > which is too slow to use the pulsin. I could use multiple magnets on
> > the wheel but I would really like to avoid that. I thought I could
> > use the LM2907(freq to voltage converter) followed by an ADC but I
> > found the low frequency produced too much ripple. Based on time I
> > would need about a .001sec resolution. The easy to use clock chips
> > seem to have only 1sec resolution. Any suggestions on how I could
> > solve this problem?
I am now educated.
SmD
Original Message
From: Michael Licitra [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DazM5dom8m6RLZsuHlObSsnHq7gBs1JNwnbim69ru7_2AebdIGbbPgcAOf1o5jXh1MDjzW9o_Ao]mikel2@b...[/url
Sent: Friday, May 26, 2000 1:06 PM
To: basicstamps@egroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
I have done this with a stamp.
connect 1 magnet to a wheel with a hall effect sensor.
Connect an oscillator to a binary counter (couple hundred Hz) and the hall
effect sensor to the stamp.
When the wheel goes around it will pulse the stamp which will read the
counter then reset it. The longer it takes the wheel to go around the
higher the counter gets. Some simple math after that.
The smack shack rare earth magnets work with a jameco hall effect sensor.
This worked until I got pics :-)
Mike
Original Message
From: <jimsp@y...>
To: <basicstamps@egroups.com>
Sent: Friday, May 26, 2000 8:36 AM
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
>
>
>
>
>
coil biased by a Radio Shack toroid-shaped permanent magnet. It was mounted
in a plastic box and clamped to the fork. Every passing spoke produced a
pulse, so the resolution was very good. The output pulses were ~100-200mv
and needed some squaring up. A crystal oscillator (tv color burst xtal &
IC) was counted down to provide a counter gate, which translated to MPH.
Distance was measured by total count.
Nowadays we use one of the $30 units Stew referred to. It uses one wheel
magnet, and doesn't have the resolution of my old one, but it sure is much
smaller, and good enough.
Ray McArthur
> I'm trying to use the BS2 to measure and periodically log the speed
> of a bicycle. The wheels would be turning in the 60 to 600rpm range
> which is too slow to use the pulsin. I could use multiple magnets on
> the wheel but I would really like to avoid that. I thought I could
> use the LM2907(freq to voltage converter) followed by an ADC but I
> found the low frequency produced too much ripple. Based on time I
> would need about a .001sec resolution. The easy to use clock chips
> seem to have only 1sec resolution. Any suggestions on how I could
> solve this problem?
Another 'spin' on the two magnets setup: the bike will travel some (small)
distance as the magnets pass by. Figure how far and measure the time it
took to go that distance.
>
Original Message
>From: <jimsp@y...>
>To: <basicstamps@egroups.com>
>Sent: Friday, May 26, 2000 5:36 AM
>Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
>
>
>> I'm trying to use the BS2 to measure and periodically log the speed
>> of a bicycle. The wheels would be turning in the 60 to 600rpm range
>> which is too slow to use the pulsin. I could use multiple magnets on
<SNIP>
Date: Fri, 26 May 2000 12:36:06 -0000
From: jimsp@y...
I'm trying to use the BS2 to measure and periodically log the speed
of a bicycle. The wheels would be turning in the 60 to 600rpm range
which is too slow to use the pulsin. I could use multiple magnets on
the wheel but I would really like to avoid that.
<<<
I have a circuit somewhere that multiplied x 100 - a simple
low frequency phase lock loop - was made for getting higher
resolution from frequency counters looking at low frequency
signals without "period" function. I think the capture
range was about 1000 x variation in signal frequency range
if I remember rightly - let me know if you want me to try
dig this up [noparse][[/noparse]I think it used a CMOS 4046].
Another possibility is using the spokes interrupting a magnetic
path - that would give you x 32 or 36 usually! The spoke
nuts are brass but the spokes are steel - probably even the
stainless spokes are magnetic stainless for strength.
There are integrated permanent magnet biased inductive pickups
which put out a signal when a piece of magnetic material goes
by [noparse][[/noparse]I've seen these in disk drives to pick up the rotational
speed]. You'd have to filter out vibration caused signal with
this method. Optical interruption could also be used.
Just yesterday I saw an LED strobe on a bike that was energized
by a spoke fastened magnet. I've often considered using rim
magnets for power generation but my rims seldom stay very true
for long...
Personally I'd stay with several magnets as they are light and
simple.
Good luck with it... ride on!
> __o __ o
> _ \<,_ _ \<,_
> (_)/ (_) (_)/ (_)
> __o __ o
> _ \<,_ _ \<,_
> (_)/ (_) (_)/ (_)
>
> __o __ o
> _ \<,_ _ \<,_
> (_)/ (_) (_)/ (_)
>
> __o __ o
> _ \<,_ _ \<,_
> (_)/ (_) (_)/ (_)
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What I tried was Tracy Allen's suggestion of a programmed timer loop.
This is simply counting the number of loops the program goes though
between turns of the wheel. In my case I counted for 4 revolutions
and wrote to an eeprom during the fifth revolution. This gives me a
reading about every 36ft. It was a bit surprising how well this
worked. At 35mph(a speed that I only achieve on down hills) the count
was about 500 which gave me the .1rpm resolution I was looking for.
If the number of loops was directly related to time you would
expect an inverse relation of loops to speed of loops*speed
=constant. As you might have guessed there is a fixed time
associated with counting like this so I found when I calibrated it
against my bike computer the relation was more like
(loops+X)*speed=constant.
In addition I plan to try the timers made by Peter Anderson
(http://www.phanderson.com/timer_1_2.html) which was also suggested
by Tracy. These timers are 8pin PIC12C508's programmed to work as
an event timer. The one style has a resolution of .001sec which
should work well in this application.
I just tried my speed logger on a 21mile ride(8k eeprom is good for
about 27miles)and it worked very well. The total distance came out
to within a few hundreds of a mile of what the bike computer
measured. I captured the file on my PC and used Excel to do the
calculations and plot the data.
>If your spoke nuts (if that's what they call the
>part nearest the rim???) are ferrous, this should work just fine. If not,
>you'll need a more expensive sensor....
Um, I think you mean nipples 8^]. Sorry, couldn't resist...
Duncan
very inexpensive ($10)inductive sensor gave a pulse for each tooth that was
easy to amplify and shape. If your spoke nuts (if that's what they call the
part nearest the rim???) are ferrous, this should work just fine. If not,
you'll need a more expensive sensor....
Original Message
From: jimsp@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RoQpKxX39FST3o3XSrx3GhrR1n3CFKwdFepN0pwJ_divk33eJbbIDFZZY7LC1SwlVd7VibjptKm3SQ]jimsp@y...[/url
Sent: Friday, May 26, 2000 7:36 AM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Measuring Bicycle Speed
I'm trying to use the BS2 to measure and periodically log the speed
of a bicycle. The wheels would be turning in the 60 to 600rpm range
which is too slow to use the pulsin. I could use multiple magnets on
the wheel but I would really like to avoid that. I thought I could
use the LM2907(freq to voltage converter) followed by an ADC but I
found the low frequency produced too much ripple. Based on time I
would need about a .001sec resolution. The easy to use clock chips
seem to have only 1sec resolution. Any suggestions on how I could
solve this problem?