If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

wrote in message
...
If you do maybe you can give me some guidance. I would like to be
able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs.
The
sensor needs to be very low power and the sensor/reader package
needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no
contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

https://www.google.com/search?q=wire...=2&oq=&gs_ l=

https://www.google.com/search?q=torq...bv=2&oq=&gs_l=

On Wed, 10 Dec 2014 08:27:00 -0800, etpm wrote:

If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the tap
is getting dull. The torque range is from .5 to 106 inch lbs. The sensor
needs to be very low power and the sensor/reader package needs to cost
less than $100.00. Is this possible? I am thinking about a MEMS sensor
that is powered like an RFID so that there is no contact. The signal
from the sensor will then be sent by radio to a receiver less than 15
feet away. I have been looking online but haven't yet found what I'm
looking for.
Thanks,
Eric

I don't think you'll find anything for $100 that'll last long in a machine
shop.

But that's just me being dismal.

You may be able to toss something together from parts for that much,
without the wireless part.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 12/10/2014 8:27 AM, wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

It's fun to think about one device with two orders of magnitude
dynamic range at low cost. Heck, let's make it wireless.

Do you REALLY need all that?
How much accuracy do you really need?
Wonder if you can't get the job done by monitoring
the motor current?

On Wed, 10 Dec 2014 10:26:57 -0800, mike wrote:

On 12/10/2014 8:27 AM, wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

It's fun to think about one device with two orders of magnitude
dynamic range at low cost. Heck, let's make it wireless.

Do you REALLY need all that?
How much accuracy do you really need?
Wonder if you can't get the job done by monitoring
the motor current?
I don't know exactly what I need and maybe two sensors are required.
But this is for tap sizes from 2-56 t0 1/4-20. I think I already have
the wireless part figured out. Do you know of any sensors that would
work for any part of the range? Can you at least point me in the right
direction? Current monitoring might work but I need to be able to
measure the tapping torque on several different machines.
Thanks,
Eric

On 10/12/14 19:11, wrote:
On Wed, 10 Dec 2014 10:26:57 -0800, mike wrote:

On 12/10/2014 8:27 AM, wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

It's fun to think about one device with two orders of magnitude
dynamic range at low cost. Heck, let's make it wireless.

Do you REALLY need all that?
How much accuracy do you really need?
Wonder if you can't get the job done by monitoring
the motor current?
I don't know exactly what I need and maybe two sensors are required.
But this is for tap sizes from 2-56 t0 1/4-20. I think I already have
the wireless part figured out. Do you know of any sensors that would
work for any part of the range? Can you at least point me in the right
direction? Current monitoring might work but I need to be able to
measure the tapping torque on several different machines.
Thanks,
Eric
Do you actually need strain sensors, on the few occasions I've looked at
them they looked like trouble unless you were doing them frequently. In
the past I work for a company that made force and torque testing
equipment and under $100 doesn't seem reasonable.

I'm wondering in this case if you could use something like a power
steering sensor idea where you have a bar transmitting the torque and
measure the angular displacement due to the torque transmitted with a
simple potentiometer. You might have to make and calibrate it but that's
half the fun.

On Wed, 10 Dec 2014 19:55:19 +0000, David Billington
wrote:
snip

I'm wondering in this case if you could use something like a power
steering sensor idea where you have a bar transmitting the torque and
measure the angular displacement due to the torque transmitted with a
simple potentiometer. You might have to make and calibrate it but that's
half the fun.

Even easier would be using two "tone" wheels or encoders at
the top and bottom of the torque bar. One wheel generates
both RPM and angular position data, the other wheel
generates position data. with the rpm known and the relative
change in the angular position as a function of time it
should be easy to calculate the torque load and calibrate
the time offset using dead weight testing.


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

wrote in message ...
On Wed, 10 Dec 2014 10:26:57 -0800, mike wrote:

On 12/10/2014 8:27 AM, wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

It's fun to think about one device with two orders of magnitude
dynamic range at low cost. Heck, let's make it wireless.

Do you REALLY need all that?
How much accuracy do you really need?
Wonder if you can't get the job done by monitoring
the motor current?
I don't know exactly what I need and maybe two sensors are required.
But this is for tap sizes from 2-56 t0 1/4-20. I think I already have
the wireless part figured out. Do you know of any sensors that would
work for any part of the range? Can you at least point me in the right
direction? Current monitoring might work but I need to be able to
measure the tapping torque on several different machines.
Thanks,

The usual method is to physically bond a couple pieces of carbon to a "window" that's been machined into your test link so that whenever the link is stretched they will change resistance a little, another two resistors are added that do not get stretch and the whole works are wired together making up a circuit that's called a "wheatstone bridge"

HTH

On Wed, 10 Dec 2014 10:26:57 -0800, mike wrote:

On 12/10/2014 8:27 AM, wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

It's fun to think about one device with two orders of magnitude
dynamic range at low cost. Heck, let's make it wireless.

Do you REALLY need all that?
How much accuracy do you really need?
Wonder if you can't get the job done by monitoring
the motor current?

Thats what I would be looking at. Motor current tells much in cases
like this.

Gunner

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

In article , Edward A. Falk
wrote:

In article ,
wrote:
If you do maybe you can give me some guidance. I would like to be able
to measure the torque required to drive taps so that I know when the
tap is getting dull. The torque range is from .5 to 106 inch lbs. The
sensor needs to be very low power and the sensor/reader package needs
to cost less than $100.00. Is this possible? I am thinking about a
MEMS sensor that is powered like an RFID so that there is no contact.
The signal from the sensor will then be sent by radio to a receiver
less than 15 feet away. I have been looking online but haven't yet
found what I'm looking for.
Thanks,
Eric

When I was a kid, I had a summer job working with strain gauges. Those
are little slips of plastic, about half the size of a postage stamp,
that has a metal trace zig-zagging back and forth across (soldering
wires to it was a bitch).

We then adhered the strain gauge onto a Lexan rod which could be dipped
into a stream of flowing water. The water flow would bend the rod and
register on the strain gauge. Voila! A flow meter with no moving parts.

The design wasn't very stable, though. It would have been better to glue
to gauges onto opposite sides of the rod and look at the differential.

Strain gauges are pretty cool. They weigh airliners and other really
heavy things by having them roll onto steel blocks with strain gauges
attached to the blocks. The blocks compress under the load and the strain
gauges measure the change.

As for your application, I would think that gluing a couple of strain
gauges to the sides of the handles of the tap-holder. This would allow
you to measure the torque being applied to the tap.

If there are no handles, but only just a shaft, I suppose you might be
able to measure torque by gluing the gauges to the shaft at an angle. Of
course, if the shaft is spinning, it might be a challenge to attach
wires to the gauges.

I would just google for "using strain gauges to measure torque"; this
must be a solved problem already.

It is a solved problem for sure. They put a set of four strain gauges
around the diameter, connected in a bridge, with gauge long axis at 45
degrees to the length. When the rod is twisted, one set of gauges
lengthen, the other set shortens.

If the rod is rotating, one find a wireless way to get drive onto the
rid and torque signals off the rod, because the strain gauges are
spinning with the rod.

There are many books on how to use strain gauges.

Joe Gwinn