Searching \ for '[EE]: Hall Sensors' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/io/sensors.htm?key=sensor
Search entire site for: 'Hall Sensors'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: Hall Sensors'
2001\06\19@075539 by Andrew Kunz

flavicon
face
Hi All,

Been a while since I've been around, but I need help again.

I need to gain a little understanding on Hall sensors, I think.

I need to "see" a steel setscrew (grubscrew) in a fiber wheel as the wheel
rotates at varying RPM from 1000 RPM to 60000 RPM.  I'm only interested in
determining instantaneous RPM, not in position data.

Does anybody know of products which work in this situation?

Thanks.

Andy

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spam_OUTlistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@080812 by Jinx

face picon face
> Hi All,

Hi yourself, hadn't seen you around for a while

> Does anybody know of products which work in this situation?

Yes, I've done a little experimenting with Allegro's HE sensors.

From the data sheets I have here, the typical Rise/Fall times
are in the range 100ns-400ns, which sounds like they should
suit your 60kHz app OK. Some part numbers are

A3046EU, 3056, 3058
UGN3055, 3059, 3113,3120, 3130,3140
A3121,3122,3123

There are plenty more, Allegro make a ton of them in all kinds
of flavours

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@080825 by Alan B. Pearce

face picon face
>I need to "see" a steel setscrew (grubscrew) in a fiber wheel as the wheel
>rotates at varying RPM from 1000 RPM to 60000 RPM.  I'm only interested in
>determining instantaneous RPM, not in position data.

I suspect you may find an inductive sensor may be easier to use. These
consist of a permeable core with a coil wound on it. The core may have some
residual magnetism built in to give the necessary magnetic field for the
rotating metal to modify the field, and then an op amp to amplify the signal
up to a level where a comparator can be used.

To use a hall sensor the rotating metal will probably need to be magnetised,
and depending on the sensor used may need amplifying. I am not sure that you
will get enough field from a grub screw like you mention to properly trigger
a hall sensor that gives a digital output unless there are sensitive ones I
do not know of.

At 60k rpm you will may need to have 2 set screws to balance the wheel
properly.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamKILLspammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@081024 by Jinx

face picon face
> suit your 60kHz app OK

Sorry, you said 60,000 rpm = 1kHz. Even better. Allegro
make quite a few for counting rotating gear teeth

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@081821 by Alan B. Pearce

face picon face
>Sorry, you said 60,000 rpm = 1kHz. Even better. Allegro
>make quite a few for counting rotating gear teeth

I don't think he did, he said the speed range of interest was 1000 RPM to
60,000 RPM. However a sensor designed to count gear teeth may well be better
than the inductive sensor I suggested.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email EraseMElistservspam_OUTspamTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@082855 by Andrew Kunz

flavicon
face
>Hi yourself, hadn't seen you around for a while

Have been too busy to even be subscribed.  Every now and then I check the
archives for interesting items.  Doesn't look like much has changed other than a
few names.

I'm just plain swamped.

Andy

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@083603 by Jinx

face picon face
> However a sensor designed to count gear teeth may well be better
> than the inductive sensor I suggested.

Here are some extracts from the A3046EU - A3058EU data sheet
er, (c) Allegro btw so no printing this out and selling it please

The AE3046 blah blah Hall Effect gear-tooth sensors are monolithic
ICs that switch in response to differential magnetic fileds created
by ferrous targets.........When combined with a back-biasing magnet
and proper assembly techniques devices can be configured to
give 50% duty cycle or to switch on either leading, trailing or both
edges of a passing gear tooth or slot..............on-board regulator
permits operation with supply voltages of 4.5 to 24V The output
stage can switch up to 20mA at conservative specified repetition
rates to 20kHz and is compatible with bipolar and CMOS

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email @spam@listservKILLspamspammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@084842 by Roman Black

flavicon
face
Andrew Kunz wrote:
>
> Hi All,
>
> Been a while since I've been around, but I need help again.
>
> I need to gain a little understanding on Hall sensors, I think.
>
> I need to "see" a steel setscrew (grubscrew) in a fiber wheel as the wheel
> rotates at varying RPM from 1000 RPM to 60000 RPM.  I'm only interested in
> determining instantaneous RPM, not in position data.
>
> Does anybody know of products which work in this situation?


Hi Andrew, yep the allegro sensors Jinx posted
about will do the high speed stuff, these are
incorporated in high speed motors and sense the
multi poles so I know 1kHz will be ok. The ones in
some motorcycle speedo sensors work at 4kHz+ ok.

A trick with sensing a tiny metal grubscrew
is to use an external magnetic field, like a
small (stationary!) strong magnet next to your
hall sensor, and as the screw goes past it affects
the flux near the sensor. You might even have to
get some steel "poles" and make a small airgap,
but with fiddling i'm sure you could get it working
ok.

So the big question is, why not use optical? Metal
grit will build up on the hall magnet, could be
nasty. But optical has it's own problems. Optical
will never have a mechanical effect or load the
shaft though...
-Roman

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email KILLspamlistservKILLspamspammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@092058 by Jinx

face picon face
> Doesn't look like much has changed other than a few names.

Just to protect the innocent

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email RemoveMElistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@103848 by Andrew Kunz

flavicon
face
>So the big question is, why not use optical? Metal

High grease environment, little metalic debris to be concerned with.  The grease
will blind the eye too easily.

The shaft is being spun by a 3000W motor - I don't think a setscrew for the hall
sensor will put much load on it.  The fiber disk will be weighing anywhere from
2-6 ounces, so balance issues are immaterial as well.

Earlier post I had 60K RPM - should have been 35K.  I don't know where 60K came
from (probably crossover noise from another project I'm working on).

Andy

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spamBeGonelistservspamBeGonespammitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@150659 by Olin Lathrop

face picon face
> I need to "see" a steel setscrew (grubscrew) in a fiber wheel as the wheel
> rotates at varying RPM from 1000 RPM to 60000 RPM.  I'm only interested in
> determining instantaneous RPM, not in position data.
>
> Does anybody know of products which work in this situation?

I worked with a company a few years ago that was making a totally new sensor
for this kind of purpose.  It detects changes in magnetic field similarly to
a coil, but is much cheaper to produce than a coil.  They were making
versions with permanent magnets in them so that the thing being sensed
didn't have to be magnetized.

I helped them with two point products using their sensors, a tachometer and
a fluid flow meter.  These used a 16C923.  The CCP module measured the
period between pulses, and the '923 drove an LCD display directly to display
the result.

The company has meanwhile moved to California.  At the time is was called
Spinix, http://www.spinix.com.  Don't know what may have happened to them in the
last two years.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, TakeThisOuTolinEraseMEspamspam_OUTembedinc.com, http://www.embedinc.com

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email RemoveMElistservspamTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body


2001\06\19@153611 by Andrew Kunz

flavicon
face
>The company has meanwhile moved to California.  At the time is was called
>Spinix, http://www.spinix.com.  Don't know what may have happened to them in the
>last two years.

Thanks, Olin, that sounds like the kind of thing that would work.

Andy

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservEraseMEspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2001\06\20@154735 by Peter L. Peres

picon face
Andy, you can do the oldest trick: use an inexpensive casette tape head as
pickup. You can use an external magnet or magnetize the screw (or the
head). It is very sensitive. Picking up a #3 Philips screw head at 5 mm
and 10 rot/sec is easy and the voltage goes up with rpm. I have used LM358
amplifiers with this.

A Hall sensor is a couple of orders of magnitude less sensitive than a
magnetic head and you will have some noise problems likely. I had some.

Peter

--
http://www.piclist.com hint: To leave the PICList
EraseMEpiclist-unsubscribe-requestspammitvma.mit.edu


2001\06\20@154740 by Peter L. Peres

picon face
> sensors that count gear teeth

Eh, most gear teeth counters I know of are differential, and won't work
with a single pole (they might work with two simulating a 'tooth'). Maybe
the Allegro ones (which I do not know) will work with a single bolt.

Peter

--
http://www.piclist.com hint: To leave the PICList
RemoveMEpiclist-unsubscribe-requestEraseMEspamEraseMEmitvma.mit.edu


2001\06\22@052424 by Jinx

face picon face
> > sensors that count gear teeth
>
> Eh, most gear teeth counters I know of are differential

A device like the UGN3059 has two quadratic Hall sensors,
differential low level amp, BP filter and a Schmitt trigger o/p.
You need to set up a field with a small magnet, which the
ferrous object perturbs and the chip detects. As the chip
responds to changing differential fields from 0Hz upwards,
it doesn't matter if there is just one "tooth" (the screw). The
chip doesn't know that's all there is

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\06\22@114948 by Dan Michaels

flavicon
face
Jinx wrote:
>> > sensors that count gear teeth
>>
>> Eh, most gear teeth counters I know of are differential
>
>A device like the UGN3059 has two quadratic Hall sensors,
>differential low level amp, BP filter and a Schmitt trigger o/p.
>You need to set up a field with a small magnet, which the
>ferrous object perturbs and the chip detects. As the chip
>responds to changing differential fields from 0Hz upwards,
>it doesn't matter if there is just one "tooth" (the screw). The
>chip doesn't know that's all there is
>


Hmmm, am getting interested in this thread. This device works
with ferrous gear teeth, and magnetic back-biasing. The specs
are a little deficient vis-a-vis "speed". Rise and fall times
are stated as 100 nsec, but in the "text" it says up to 20 khz,
~50 usec.

Rise/fall times represent the characteristics of the output
logic stages, but don't take into account the "propagation
delay" time through the hall transducer itself. I ran into this
same situation with photodiode amplifier devices that have a
logic output stage.

So the UGN3059 may be just handle Andy's app. 30,000 RPM motor
with 40 tooth gear will hit just at 20 khz.

cheers,
- dan michaels
http://www.oricomtech.com
========================

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...