Searching \ for '[EE] Picking omnipolar Hall effect 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/microchip/ios.htm?key=sensor
Search entire site for: 'Picking omnipolar Hall effect sensors'.

Exact match. Not showing close matches.
PICList Thread
'[EE] Picking omnipolar Hall effect sensors'
2017\10\28@134809 by mike brown

flavicon
face

Hello all,

I need some cheap, easily available Hall effect sensors that are switches,
omnipolar and sensitive.  I’m doing a game room project and need to sense
some magnets that are embedded within “tiles” made from three pieces of
thin plywood.  The sensors will be under a table top approximately ¾” thick
(18mm).  I can carve away some of the wood to get the sensor near the
surface.  Normally I would use reed switches, but I just can’t stand
working with their frailty.



The builder of the tiles can’t be bothered with sorting the polarity of the
neodymium magnets that are ¾” in diameter and about 3/32” thick.  These are
fairly powerful magnets that can activate a reed switch several inches
away, but not reliably when centered precisely over the reed switch.  I’m
guessing that has to do with the flux field being flattened by the large
diameter and relative thinness of the magnets.



I can get qty 10 A3144 sensors for under $5 including fast shipping, but
these are unipolar.  Is there another part number, in this price range,
that would be at least as sensitive and in a omnipolar form?  I don’t want
latches or linear devices.
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\28@140921 by Bob Blick

flavicon
face
Use two hall effect sensors mounted back-to-back?

________________________________________
From: spam_OUTpiclist-bouncesTakeThisOuTspammit.edu <.....piclist-bouncesKILLspamspam@spam@mit.edu> on behalf of mike brown
Sent: Saturday, October 28, 2017 10:48 AM
To: Microcontroller discussion list - Public.
Subject: [EE] Picking omnipolar Hall effect sensors

Hello all,

I need some cheap, easily available Hall effect sensors that are switches,
omnipolar and sensitive.  I’m doing a game room project and need to sense
some magnets that are embedded within “tiles” made from three pieces of
thin plywood.  The sensors will be under a table top approximately ¾” thick
(18mm).  I can carve away some of the wood to get the sensor near the
surface.  Normally I would use reed switches, but I just can’t stand
working with their frailty.



The builder of the tiles can’t be bothered with sorting the polarity of the
neodymium magnets that are ¾” in diameter and about 3/32” thick.  These are
fairly powerful magnets that can activate a reed switch several inches
away, but not reliably when centered precisely over the reed switch.  I’m
guessing that has to do with the flux field being flattened by the large
diameter and relative thinness of the magnets.



I can get qty 10 A3144 sensors for under $5 including fast shipping, but
these are unipolar.  Is there another part number, in this price range,
that would be at least as sensitive and in a omnipolar form?  I don’t want
latches or linear devices.

-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

2017\10\28@151521 by Mike B

picon face

A reed relay not closing when centered on the magnet is a common problem.
One solution is to surround the target with 4 sensors wired in series. All
need to be closed for a valid detection.

On Oct 28, 2017 12:50, "mike brown" <mikespamKILLspamn5qmg.com> wrote:

Hello all,

I need some cheap, easily available Hall effect sensors that are switches,
omnipolar and sensitive.  I’m doing a game room project and need to sense
some magnets that are embedded within “tiles” made from three pieces of
thin plywood.  The sensors will be under a table top approximately ¾” thick
(18mm).  I can carve away some of the wood to get the sensor near the
surface.  Normally I would use reed switches, but I just can’t stand
working with their frailty.



The builder of the tiles can’t be bothered with sorting the polarity of the
neodymium magnets that are ¾” in diameter and about 3/32” thick.  These are
fairly powerful magnets that can activate a reed switch several inches
away, but not reliably when centered precisely over the reed switch.  I’m
guessing that has to do with the flux field being flattened by the large
diameter and relative thinness of the magnets.



I can get qty 10 A3144 sensors for under $5 including fast shipping, but
these are unipolar.  Is there another part number, in this price range,
that would be at least as sensitive and in a omnipolar form?  I don’t want
latches or linear devices.
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\28@154642 by Clint Jay

picon face

Why unipolar? I had a cute little circuit using an opamp and a comparator
which would light one led or another depending on magnetic polarity, would
be trivial to diode OR the outputs together.

On 28 Oct 2017 18:50, "mike brown" <.....mikeKILLspamspam.....n5qmg.com> wrote:

{Quote hidden}

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\28@154837 by Rodolfo

flavicon
face

XY coils to sense magnetic field when neo magnets are over two coils, one  
over the other? Like a magnetic digitizer?

Rodolfo

En Sat, 28 Oct 2017 16:15:18 -0300, Mike B <EraseMEmbaum7901spam_OUTspamTakeThisOuTgmail.com> escribió:

{Quote hidden}

--
Usando el cliente de correo de Opera: http://www.opera.com/mail/

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\28@161753 by RussellMc

face picon face

On 29 October 2017 at 06:48, mike brown <@spam@mikeKILLspamspamn5qmg.com> wrote:

> Hello all,
>
> I need some cheap, easily available Hall effect sensors that are switches,
> omnipolar and sensitive.


AH180
Much used in Asia.

Bipolar (2 Hall plates) with chopper stabilisation.
8/24 uA average typ/max
2.5 - 5 VDC
~= +/- 5 mT operate
~= +/- 1 mT release

Low current achieved by using sampling - 0.1% on time.
100 +/- 10 ms sampling interval - so MAY not be suitable in your application

Diodes inc make them so they must be good :-)

        https://www.diodes.com/assets/Datasheets/AH180.pdf


Digikey 50,000+ in stock
$US0.54/1
$US0.18x / 3000

https://www.digikey.com/products/en/sensors-transducers/magnetic-sensors-switches-solid-state/565?k=ah180

Russell

​
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\28@182046 by mike brown

flavicon
face
Thanks to everyone for your input.  This is what I really like about
asking here, five responses every one is unique.

Bob - I have to admit that never crossed my mind, but it sounds like a
workable solution.  I'd probably put them next to each other, one face up
and the other face down.  I'll do some experiments with that.

Mike B - I'm glad it's not just me.  Good idea on making a ring of reed
switches.  Since these will be embedded in tiles, positioning accuracy
will not be an issue.

Clint - The magnet must be sensed without regards to which pole is
presented, though I suppose I could make a sorter circuit for the guy
building the tiles so that he always puts the magnets in the right way.

Rodolfo - I'm not sure I understand what you mean.

Russell - Thanks, I'll check availability of those here.  So, the "brain"
in the Hall sensor sleeps most of the time and polls for a field every
100mS or so.  Does it keep the output latched until the next poll cycle,
or would I be seeing 100uS pulses every 100mS?  The prop will likely be
battery operated and sleeping for most of the time.  I'd planned to just
poll all of the sensors after sleep and logically AND them all.  If there
are pulses, I could manage but it would add a lot of complication
(relatively speaking) to the code.
-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

2017\10\29@013907 by RussellMc

face picon face

On 29 October 2017 at 11:20, mike brown <KILLspammikeKILLspamspamn5qmg.com> wrote:


> Russell - Thanks, I'll check availability of those here.


​Where is "here"?
​

> So, the "brain"
> in the Hall sensor sleeps most of the time and polls for a field every
> 100mS or so.  Does it keep the output latched until the next poll cycle,
> or would I be seeing 100uS pulses every 100mS?


​Output is latched and changes if required at wakeup time.
See diagrams in datasheet at bottom of pages 2 & 3.


​Datasheet

        https://www.diodes.com/assets/Datasheets/AH180.pdf


​Russell

​

<https://www.diodes.com/assets/Datasheets/AH180.pdf>



> The prop will likely be
> battery operated and sleeping for most of the time.  I'd planned to just
> poll all of the sensors after sleep and logically AND them all.  If there
> are pulses, I could manage but it would add a lot of complication
> (relatively speaking) to the code.
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\29@070519 by Justin Richards

face picon face

I had a quick play with cheap switching hall effect sensors from ebay.
They had similar sensitivity to a reed.  I was not aware they may respond
differently to the poles. Will test again when I get home.  This may help
solve a problem I have been having to uniquely identify 4 out of 8 foam
balls.

I use reeds end on and find the are very sensitive used this way. The
effective pattern is definitely a figure 8.  Typically I cut the legs
short,  bend one leg all the way back (with needle nose pliers supporting
the leg at the glass end because as you say they are very delicate) so
effectively forming a U shape with one leg running beside the glass.  The
shortened lead are then soldered.

To install a small hole is drilled underneath the table or prop. Push reed
into the hole and pot with hot glue encapsulating the solder joints etc.
They are very robust once potted and you can get the sensitive end of the
reed very close to the surface with no visible signs (unless you happen to
drill all the way thru).

I have recently experimented with reeds in an attempt to improve the
precision.  I tried various things to shield one end so it would only be
sensitive to a magnets approach at the other end but it proved to be
futile. It maybe doable if I had a lathe etc. This was to help solve the
uniquely identify 4 out of 8 small foam balls mentioned above.

Justin

On 29 October 2017 at 01:48, mike brown <RemoveMEmikeTakeThisOuTspamn5qmg.com> wrote:

{Quote hidden}

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\29@081405 by RussellMc

face picon face

On 30 October 2017 at 00:05, Justin Richards <spamBeGonejustin.richardsspamBeGonespamgmail.com>
wrote:

>
> I use reeds end on and find the are very sensitive used this way. The
> effective pattern is definitely a figure 8.  Typically I cut the legs
> short,  bend one leg all the way back (with needle nose pliers supporting
> the leg at the glass end because as you say they are very delicate) so
> effectively forming a U shape with one leg running beside the glass.  The
> shortened lead are then soldered.
>
>
1. As well as clamping the wire between reed and bend when forming the
wire.​ you should also

2. *When cutting reed-leads you should (must) clamp the wire between reed
and cutting point *so the shock from the cutting is not transmitted into
the reed assembly. As unlikely as it may seem, such shocks are said to
damage the wire/glass seal and may lead to 'walking wounded' early field
failures.

I designed a product that used a reed switch and 100,000+ were made. We
very carefully specified bending and cutting procedures and jigs were made
to ensure that the assemblers would have no difficulty in meeting the
requirements. We had very little trouble with the reeds - suggesting either
that they are more robust than claimed, or that our procedures were
adequate.

I found that the reed survivability under high-g impact conditions appeared
to be significantly better than the manufacturer's claims.
The product (a small solar flashlight) could be subject to c=virtually any
degree of abuse without (apparent) reed damage.

A big advantage of reed switches over even sampling Hall sensors is the
essentially zero quiescent current.
1 uA drain requires about 9 mAh of battery capacity per year.
So eg the 8 / 24 uA typical/max drain of the AH180 Hall sensor requires 70
/ 200 mAh / year to power.

Russell
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\29@094601 by Justin Richards

face picon face
>
>
> 2. *When cutting reed-leads you should (must) clamp the wire between reed
> and cutting point *so the shock from the cutting is not transmitted into
>

Great tip. Will do so from now on.

I designed a product that used a reed switch and 100,000+ were made. We
> very carefully specified bending and cutting procedures and jigs were made
>

100,000+ That is a lot of reed switches/solar flashlights. What was the
application if you care to elaborate.

Never considered the quiescent current. Good point.

Justin
-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

2017\10\29@230825 by RussellMc

face picon face

On 30 October 2017 at 02:45, Justin Richards <TakeThisOuTjustin.richardsEraseMEspamspam_OUTgmail.com>
wrote:

>
> ​>​
> I designed a product that used a reed switch and 100,000+ were made. We
> > very carefully specified bending and cutting procedures and jigs were
> made
>
>
> 100,000+ That is a lot of reed switches/solar flashlights.


​Total numbers uncertain without checking.
30,000 in Haiti. Various 10,000 - 20,000 batches elsewhere.



> What was the
> application if you care to elaborate.
>
> ​Small flashlight in photos here


http://public.fotki.com/RussellMc/atw/bogo/sl2africa01/?view=roll#19

Roll with cursor keys or PgUp/PgDown or ...
"Enter" drops into a more normal / slower display mode.

Small lights have reed switch.
100% waterproof (up to some thousands of psi :-) ).
No quiescent current.
Impact limit (notionally)(the carabiner breaks off when thrown 15' in air
to land on concrete Reed survives.)

Larger lights have mechanical switch ​with attendant sealing issues.
Zero quiescent current.

Hall
​can be waterproof but has quiescent current issues.


​   Russell​
.
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\30@182743 by Dwayne Reid

flavicon
face
I really Bob Blick's answer.

But a different approach could use a linear Hall Effect sensor.  No magnetic field has the output sitting at half the rail voltage.  Increasing magnetic field has the output move away from the half-rail value: towards either Vdd or Vss, depending upon polarity.

Seems like it would be trivial to detect the field.

dwayne


At 11:48 AM 10/28/2017, mike brown wrote:
{Quote hidden}

-- Dwayne Reid   <RemoveMEdwaynerspamTakeThisOuTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
780-489-3199 voice   780-487-6397 fax   888-489-3199 Toll Free
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing


-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

2017\10\30@194435 by RussellMc

face picon face

A number of possibly useful files (+ some less relevant but 'interesting'
Hall effect related files) that I have downloaded are (perhaps temporarily)
in a Dropbox folder here

            http://bit.ly/rusl_hall_sensors

An index of the files is in INDEX.TXT


On 31 October 2017 at 11:04, Dwayne Reid <dwaynerEraseMEspam.....planet.eon.net> wrote:

>
> But a different approach could use a linear Hall
> Effect sensor.  No magnetic field has the output
> sitting at half the rail voltage.  Increasing
> magnetic field has the output move away from the
> half-rail value: towards either Vdd or Vss, depending upon polarity.
>

​An advantage of a linear sensor is that hysteresis can be altered to suit.

The AH180 ​that I mentioned appears to have models with several
operate/release ratios and ranges of field strengths, and each magnet
polarity has somewhat different  operate/release characteristics.
Such variations in a linear device could be accommodate by external
circuitry if desired.

It would be worth having a look at *Digikey's AH180 product page
<https://www.digikey.com/products/en/sensors-transducers/magnetic-sensors-switches-solid-state/565?k=ah180>*,
regardless of which Hall sensor you end up using.

My experience with reed switches suggests that they should be easily robust
enough and would easily meet your application.
Reed orientation relative to the moving magnet has significant effect.


Russell
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\30@214440 by smplx

flavicon
face
part 1 1765 bytes content-type:text/plain; charset="utf-8" (decoded base64)



On Tue, 31 Oct 2017, RussellMc wrote:

> A number of possibly useful files (+ some less relevant but 'interesting'
> Hall effect related files) that I have downloaded are (perhaps temporarily)
> in a Dropbox folder here
>
>             http://bit.ly/rusl_hall_sensors
>
> An index of the files is in INDEX.TXT
>
>
> On 31 October 2017 at 11:04, Dwayne Reid <EraseMEdwaynerspamplanet.eon.net> wrote:
>
>>
>> But a different approach could use a linear Hall
>> Effect sensor.  No magnetic field has the output
>> sitting at half the rail voltage.  Increasing
>> magnetic field has the output move away from the
>> half-rail value: towards either Vdd or Vss, depending upon polarity.
>>
>
> ‚ÄčAn advantage of a linear sensor is that hysteresis can be altered to suit.
>
> The AH180 ‚Äčthat I mentioned appears to have models with several
> operate/release ratios and ranges of field strengths, and each magnet
> polarity has somewhat different  operate/release characteristics.
> Such variations in a linear device could be accommodate by external
> circuitry if desired.
>
> It would be worth having a look at *Digikey's AH180 product page
> *,
> regardless of which Hall sensor you end up using.
>
> My experience with reed switches suggests that they should be easily robust
> enough and would easily meet your application.
> Reed orientation relative to the moving magnet has significant effect.

Just curious but would the operator not experience feedback on the moving
magnet? And if so could this not be used by the operator to locate hidden
reed switches?

Regards
Sergio Masci
part 2 197 bytes content-type:text/plain; name="ATT00001.txt"
(decoded base64)

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2017\10\30@230825 by RussellMc

face picon face

On 31 October 2017 at 15:49, smplx <RemoveMEsmplxEraseMEspamEraseMEallotrope.net> wrote:

>
> Just curious but would the operator not experience feedback on the moving
> magnet? And if so could this not be used by the operator to locate hidden
> reed switches?
>
>
Using force, potentially yes. But the force is extremely small. ​
Scattering a few iron nails around the place would mask the ability.

Using sound, maybe. The reeds make a small but distinctive sound when they
operate.
​Unlikely to be audible through typical material coverings - unless you had
eg a conduction microphone ​adjacent. Adding FFT and filtering may help.

M61 is liable to be a surer way of getting out (but less compact).


   Russell
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist


'[EE] Picking omnipolar Hall effect sensors'
2017\11\28@162245 by Alan
picon face
Late but...
I just spotted an omnipolar Hall effect ic from Rohm. Has two outputs that could probably be diode anded. One for each magnet polarity.
BU52075GWZ-E2
www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=145692848
Draws 5uA
$.48 for one $.20ea for 100
Looking forward,
Al Shinn (Tinker)

-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

2017\11\29@192005 by RussellMc

face picon face
Datasheets. Different operating voltages & ...


http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/hall/bu52004gul-e.pdf


http://www.rohm.com/web/global/datasheet/BU52075GWZ/bu52075gwz-e.pdf

Like the ones that I mentioned, these obtain their low Iq by sampling the
inputs.
Nominal sampling interval is 50 mS but can be 100 mS worst case.

Outputs are true bipolar so as Allan says, ORing is needed.
Diodes 'should work' OK.

Package is either tiny or very tiny.
HVS0F5 1.6mm x 1.2mm is leaded.
VCSC50L1 is 1.1mm x 1.1mm mit bumps.



         Russell

On 29 November 2017 at 10:22, Alan <RemoveMEalshinnspam_OUTspamKILLspammindspring.com> wrote:

{Quote hidden}

-- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist
.

More... (looser matching)
- Last day of these posts
- In 2017 , 2018 only
- Today
- New search...