Tire Pressure Sensor

[Luhan Monat]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

 

[Tim Wescott]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

Motorola made these -- I don't know if they went to On or FreeFall, but
IIRC Digi-Key sells them.

 

[Luhan Monat]

Motorola made these -- I don't know if they went to On or FreeFall, but
IIRC Digi-Key sells them.

Thanks, I found one for under $20 that goes to 36 psi. As long as it
can take about 100% overload without dammage, that may do the trick.

 

[Spehro Pefhany]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

This is a killer app for cars 'n trucks. Sensor plus uP plus very low
power (eg. Zigbee) wireless interface = big bux for the semiconductor
companies. Especially if it gets government mandated.


Best regards,
Spehro Pefhany

 

[Joerg]

Hello Spehro,

This is a killer app for cars 'n trucks. Sensor plus uP plus very low
power (eg. Zigbee) wireless interface = big bux for the semiconductor
companies. Especially if it gets government mandated.

It already exists. One of the guys on the German electronics forum
(Oliver Bartels) developed such a system. I believe he also used to race
Formula One rods so he should know what he's talking about.
Unfortunately the pubs are only in German:

http://www.tyretronic.com/index.php?m=200202___AANDE_200201&language=en

In that article it is mentioned that the US mandates it already but I
doubt that.

I can see this for car tires although I check mine every other week. But
for bicycles? On mine I just sit on it and then I know. Usually the
pressure is digital. It is either ok, or it went kapoof.

Regards, Joerg

 

[Fred Bloggs]

As long as it
can take about 100% overload without dammage, ...

It won't.

 

[Doug Warner]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

Some car systems use an indirect method, where they measure RPM of all
the wheels via the ABS sensors and, if one wheel begins to roll faster
because it's diameter decreases with a pressure drop, it signals an
alert.

I suppose the same could be done on a bicycle, using two magnetic
pickups and a a form of deluxe speedometer that also does the speed
comparision and alerting..
It won't give you the absolute pressure, and it only works if ONE tire
loses pressure.

To reply, please remove one letter from each side of "@"
Spammers are VERMIN. Please kill them all.

 

[Fred Bloggs]

Hello Spehro,



It already exists. One of the guys on the German electronics forum
(Oliver Bartels) developed such a system. I believe he also used to race
Formula One rods so he should know what he's talking about.
Unfortunately the pubs are only in German:

http://www.tyretronic.com/index.php?m=200202___AANDE_200201&language=en

In that article it is mentioned that the US mandates it already but I
doubt that.

I can see this for car tires although I check mine every other week. But
for bicycles? On mine I just sit on it and then I know. Usually the
pressure is digital. It is either ok, or it went kapoof.

Regards, Joerg

Well- the air volume is so small that it takes next to nothing to lose
pressure- they should be checked before every ride anyway- along with a
quick inspection of the frame for cracks. A gauge should be integral to
your pump- I have found that it is real easy to make that tire explode
with the hand pump- and then you will be hearing impaired for a few
hours or so.

 

[Paul Hovnanian P.E.]

Hello Spehro,


It already exists. One of the guys on the German electronics forum
(Oliver Bartels) developed such a system. I believe he also used to race
Formula One rods so he should know what he's talking about.
Unfortunately the pubs are only in German:

http://www.tyretronic.com/index.php?m=200202___AANDE_200201&language=en

In that article it is mentioned that the US mandates it already but I
doubt that.

That's correct, for now. But a mandate is coming soon.

 

[Luhan Monat]

Hello Spehro,



It already exists. One of the guys on the German electronics forum
(Oliver Bartels) developed such a system. I believe he also used to race
Formula One rods so he should know what he's talking about.
Unfortunately the pubs are only in German:

http://www.tyretronic.com/index.php?m=200202___AANDE_200201&language=en

In that article it is mentioned that the US mandates it already but I
doubt that.

I can see this for car tires although I check mine every other week. But
for bicycles? On mine I just sit on it and then I know. Usually the
pressure is digital. It is either ok, or it went kapoof.

Regards, Joerg

Trouble is, slow leaks are hard to spot while riding until its way too
late. This is a real issue, worth doing an RF/Micro system on the rear
wheel (which tends to get all the leaks). Test for both pressure level,
and change in pressure to warn as much ahead as possible.

I already have a micro based alarm system activated by RF remote. So, I
only need to do the hard work on the transmitting end. Something
sending out a code every 10 turns of the wheel or so to save on battery.

Yes, these systems already exist; but all I'm lacking is the sensor
itself to make a working device for myself. Also, the commercial ones
dont allow for 'leak rate' detection, they only trip a tranmitter on a
specific pressure.

 

[rob]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

What about a small adjustable pressure switch mounted on the valve
(counterweight opposite if needed). Thin wire back to a battery mounted near
the hub/axle. Then via LED or whatever to a frame mounted sensor which is
read every wheel rotation. Sorry no micro or Zigbee.

 

[Al]

That's correct, for now. But a mandate is coming soon.

Yeah, in the US it's been mandated for most vehicles in 2008.

Another gadget to keep up safe! Jeesh, what ever happened to checking
your tire pressure weekly? The idiots seem to be driving our technology.
More junk to break down and have fixed for yearly inspection.

Al

 

[Si Ballenger]

Thanks, I found one for under $20 that goes to 36 psi. As long as it
can take about 100% overload without dammage, that may do the trick.

You can get a digital tire pressure gage with LCD readout at
walmart for ~$10. From there you would need to do some hacking to
get something useful for your application.

 

[Joerg]

Hello Al,

Another gadget to keep up safe! Jeesh, what ever happened to checking
your tire pressure weekly? The idiots seem to be driving our technology.
More junk to break down and have fixed for yearly inspection.

Common sense seems on the way out. I mean, if people even need a
reminder on coffee cups "caution - HOT - can cause serious injury".

In Europe some folks think they can't even live without ultrasound
parking aids in the bumpers. Oh man.

Regards, Joerg

 

[Jim Thompson]

Hello Al,


Common sense seems on the way out. I mean, if people even need a
reminder on coffee cups "caution - HOT - can cause serious injury".

In Europe some folks think they can't even live without ultrasound
parking aids in the bumpers. Oh man.

Regards, Joerg

In Boston, no ultrasonics need, they park by ear... clang, clang ;-)

...Jim Thompson

 

[Joerg]

Hello Luhan,

Trouble is, slow leaks are hard to spot while riding until its way too
late. This is a real issue, worth doing an RF/Micro system on the rear
wheel (which tends to get all the leaks). Test for both pressure level,
and change in pressure to warn as much ahead as possible.

True. But when I was in driving school they still taught us how to watch
for weird behavior of the vehicle. Low pressure, ice, slush etc. They
also taught us how to react.

Most cars are pretty good though. I was at a customer, had half their
R&D Department in a rented Saturn L300 when the right rear decided to
deflate on a county road. None of us even felt much until we were
parked, except that the car became somewhat sluggish. It remained
remarkably stable.

Regards, Joerg

 

[Joerg]

Hello Rob,

What about a small adjustable pressure switch mounted on the valve
(counterweight opposite if needed). Thin wire back to a battery mounted near
the hub/axle. Then via LED or whatever to a frame mounted sensor which is
read every wheel rotation. Sorry no micro or Zigbee.

We did something similar for a large diesel drive shaft, to measure
torque flutter etc. which could indicate upcoming engine problems.
Balanced strain gauge on the shaft, inductive coupling to a stationary
coil. No micro, no Zigbee, no battery. Well, neither Zigbee nor
Bluetooth were around at that time anyway.

Regards, Joerg

 

[Al]

In Boston, no ultrasonics need, they park by ear... clang, clang ;-)

...Jim Thompson

In the 60's, while a student, the massive bumpers on my '47 Pontiac
could really dish it out.

Al

 

[Jim Thompson]

In the 60's, while a student, the massive bumpers on my '47 Pontiac
could really dish it out.

Al

I had a '61 Dauphine with tubular wrap-arounds that offered
substantial protection.

...Jim Thompson

 

[Dave Garnett]

Hi,

I would like to make a remote tire pressure monitor (0-50 psi) for my
bicycle. Any ideas on where to get a sensor cheap? Accuracy is not
critical, as long as temperature drift is not excessive.

Instead of pressure, how about measuring how flat the tyre is ? Insert into
the valve stem a sort of plunger that is spring loaded against the inner
tube and tyre. Every time the wheel goes round the plunger will be
compressed and released. You could make the motion generate a voltage to
turn the electronics on, and then measure the change in inductance to get
the actual distance moved. You might even be able to extract enough power to
power a short transmit burst, and hence need no batteries ...

You would need a filter for an alarm so that the odd bump didn't register,
but a gradual change would ...

Dave