New Polymer Neodium magnet VIDEO, standard pickup constructions tests and comparison

[David Schwab]

ok i'm very nervous so this is my last post here....

but the point is not the value of the magnet that you have at home .... (...you have enough fantasy to invent a new formula that measures the value that you would like it has. )

the point to be clarified is why you insult me saying my meter don't work... and you did not reply about your fantasy formula/measurements????

please explain your formula...

bye

I have a question, because I don't remember how it was done. I remember that the sensors were all calibrated to something. How was that done again?

I also seem to remember that someone checked a magnet on a commercial gauss meter and then against yours, or maybe they sent that magnet around to a few people for comparison?

Anyway, I brought this up because after using your meter for a while now it does seem accurate when used with known magnets. And since some of the polymer NiB magnets more closely matched some ceramics I have here, which are obviously higher than the rating on the NiBs, I feel pretty confident that the stated value on the NiBs is in error.

[RedHouse]

I have a question, because I don't remember how it was done. I remember that the sensors were all calibrated to something. How was that done again?

I also seem to remember that someone checked a magnet on a commercial gauss meter and then against yours, or maybe they sent that magnet around to a few people for comparison?

Anyway, I brought this up because after using your meter for a while now it does seem accurate when used with known magnets. And since some of the polymer NiB magnets more closely matched some ceramics I have here, which are obviously higher than the rating on the NiBs, I feel pretty confident that the stated value on the NiBs is in error.

David, recall that in the intitial round of the Gauss Meter Group Buy, I coordinated the purchase all the parts, received the PIC's from Elepro, and bagged and shipped all the "parts kits".

When we were working it all out here on this forum, the notion of accuracy arose and was mutually agreed by all concerned parties that for the group buy to move forward everyone would need to be assured of reasonable accuracy with real-world magnets. This is probably the calibration you're thinking of.

Since I was at the wheel of the group-buy, and since I live the Puget Sound area of Washington state, where a couple of top-notch winders reside (Lollar and McLeod) who both had commercial gauss meters, I volunteered to meet with them, and they were willing, and did a quick comparison of the Elepro meter to the commercial meters with the same set of magnets.

On Saturday I went up to Wolfe's place and we did the deed and found the Elepro kit measuring a bit off ...but... calibration was able to bring it in-line with Wolfe's meter. The next day I went over to Lollars place and did the same thing, and since the previous day's calibration, the readings were accurate with Jason's meter.

Back at my place, with a bag of sensors in hand, I hooked each sensor up to the same (Elepro) meter used with Jason/Wolfe comparison testing and noted what setting each sensor needed to be re-calibrated to get the exact same reading on the same magnets used with the Jason/Wolfe comparison testing the days before. I placed a piece of masking tape on each one and wrote the calibration value so each person who bought the parts kit could dial-in their meter after assembling it, and be confident of it's accuracy.

Note that out of the 30-odd sensors I tested/noted their calibration settings, only 6 or 7 sensors were spot-on, all the rest needed calibration, some needed more than others to read the same magnets and get the same reading as Wolfe's and Jason's meters gave.

These were the 3-pin (Allegro 1302?) sensors not the SOIC Analog Devices 22151 sensors which were used later in the other group buy's (which I had nothing to do with). Unless those on the other group buys have found a commercial meter to test aganst their Elepro meter, they're un-calibrated, and in the experience of the initial group-buy (7 out of 30-odd sensors) we can only assume they are not accurate.
(YMMV)

Going by memory (Warning will Robinson!) it seems like the Allegro has an upper gauss limit of 1200 or so gauss and wouldn't do well testing Neo's, that's why the meter evolved into the dual-sensor design and used the AD22151 which was capable of going much higher.

[MrCandy]

I have a question, because I don't remember how it was done. I remember that the sensors were all calibrated to something. How was that done again?

I also seem to remember that someone checked a magnet on a commercial gauss meter and then against yours, or maybe they sent that magnet around to a few people for comparison?

Anyway, I brought this up because after using your meter for a while now it does seem accurate when used with known magnets. And since some of the polymer NiB magnets more closely matched some ceramics I have here, which are obviously higher than the rating on the NiBs, I feel pretty confident that the stated value on the NiBs is in error.

David, all this sensors are pretty accurate and linear. all device calibration is actual NULL checkpoint and also setting sensor sensivity params.
Meanwile with the help of simple multimeter you can determine the approximate magnet charge in gauss since voltage at the output of the sensor is proportional to the magnetic flux.
You can compare voltmeter data interpreted in the gauss with data your device shows you.
For this you need to measure NULL on A1302 sensor(no magnets nearby), then took a magnet to sensor and measure voltage on sensor out.
If you measure North, then you need Vnull - Vout to get DeltaV, if you measure south then Vout-Vnull to get DeltaV.
To find gauss value you need DeltaV/sensitivity. A1302 datasheet sensivity= 1.3mV/G (VCC on sensor = 5 V)
Check this out. There is a small error anyway but in wont be 10+ percent difference.

[David Schwab]

David, recall that in the intitial round of the Gauss Meter Group Buy, I coordinated the purchase all the parts, received the PIC's from Elepro, and bagged and shipped all the "parts kits".

When we were working it all out here on this forum, the notion of accuracy arose and was mutually agreed by all concerned parties that for the group buy to move forward everyone would need to be assured of reasonable accuracy with real-world magnets. This is probably the calibration you're thinking of.

Since I was at the wheel of the group-buy, and since I live the Puget Sound area of Washington state, where a couple of top-notch winders reside (Lollar and McLeod) who both had commercial gauss meters, I volunteered to meet with them, and they were willing, and did a quick comparison of the Elepro meter to the commercial meters with the same set of magnets.

On Saturday I went up to Wolfe's place and we did the deed and found the Elepro kit measuring a bit off ...but... calibration was able to bring it in-line with Wolfe's meter. The next day I went over to Lollars place and did the same thing, and since the previous day's calibration, the readings were accurate with Jason's meter.

Back at my place, with a bag of sensors in hand, I hooked each sensor up to the same (Elepro) meter used with Jason/Wolfe comparison testing and noted what setting each sensor needed to be re-calibrated to get the exact same reading on the same magnets used with the Jason/Wolfe comparison testing the days before. I placed a piece of masking tape on each one and wrote the calibration value so each person who bought the parts kit could dial-in their meter after assembling it, and be confident of it's accuracy.

Note that out of the 30-odd sensors I tested/noted their calibration settings, only 6 or 7 sensors were spot-on, all the rest needed calibration, some needed more than others to read the same magnets and get the same reading as Wolfe's and Jason's meters gave.

These were the 3-pin (Allegro 1302?) sensors not the SOIC Analog Devices 22151 sensors which were used later in the other group buy's (which I had nothing to do with). Unless those on the other group buys have found a commercial meter to test aganst their Elepro meter, they're un-calibrated, and in the experience of the initial group-buy (7 out of 30-odd sensors) we can only assume they are not accurate.
(YMMV)

OK, this is what I was trying to recall. Yes, my sensor had a piece of tape (I think) with the calibration offset written on it. I then entered that into the meter for that probe.
I'm using one of those Allegro sensors. I also have the other sensor, but never got around to wiring it up. So I have been using the Allegro all this time.

[David Schwab]

David, all this sensors are pretty accurate and linear. all device calibration is actual NULL checkpoint and also setting sensor sensivity params.
Meanwile with the help of simple multimeter you can determine the approximate magnet charge in gauss since voltage at the output of the sensor is proportional to the magnetic flux.
You can compare voltmeter data interpreted in the gauss with data your device shows you.
For this you need to measure NULL on A1302 sensor(no magnets nearby), then took a magnet to sensor and measure voltage on sensor out.
If you measure North, then you need Vnull - Vout to get DeltaV, if you measure south then Vout-Vnull to get DeltaV.
To find gauss value you need DeltaV/sensitivity. A1302 datasheet sensivity= 1.3mV/G (VCC on sensor = 5 V)
Check this out. There is a small error anyway but in wont be 10+ percent difference.

Read Brad's post above to see that these sensors were calibrated to two commercial gauss meters using the same target magnet. So I have no doubt that the meter I have is accurate as it matches commercially available (and calibrated) meters.

This is why I questioned your readings. You should get ahold of a commercial gauss meter and make some comparisons.

Now none of this affects how well your magnets work, just that the strength marked on them is incorrect. 60mT would have them weaker than many ceramic magnets.

[RedHouse]

David, all this sensors are pretty accurate and linear. all device calibration is actual NULL checkpoint and also setting sensor sensivity params.
Meanwile with the help of simple multimeter you can determine the approximate magnet charge in gauss since voltage at the output of the sensor is proportional to the magnetic flux.
You can compare voltmeter data interpreted in the gauss with data your device shows you.
For this you need to measure NULL on A1302 sensor(no magnets nearby), then took a magnet to sensor and measure voltage on sensor out.
If you measure North, then you need Vnull - Vout to get DeltaV, if you measure south then Vout-Vnull to get DeltaV.
To find gauss value you need DeltaV/sensitivity. A1302 datasheet sensivity= 1.3mV/G (VCC on sensor = 5 V)
Check this out. There is a small error anyway but in wont be 10+ percent difference.

Not true, see my post above.

You are just guessing and relying on the spec sheet for your accuracy statement. In practice only 6 or 7 sensors were accurate, the other 26 needed calibration.

Just because a 1301/1302 reads 1/2vc w/o a field present, certainly doesn't mean that when a field is present, it's reading it correctly.

This thinking is making it clear to me why your "findings" (in this post and others) are not exactly what one would expect.

[-Elepro-]

To find gauss value you need DeltaV/sensitivity.

you changed formula ?????

please explain your previous imaginative formula!!!!

Vmax= Vnull - Vlim
Bmax is the limit where sensor shuts.
Vmax is maximal value that determines 840gauss(Bmax)
ΔV= Vmax - Vout
Bgauss=Bmax*ΔV/Vmax

[MrCandy]

We are now negotiate with Сertification state testing center to make measurements there.
Meanwile check everything with multimeter as we offered earlier, on our side when we will get same sensor we will check everything 2.

[-Elepro-]

Not true, see my post above.

You are just guessing and relying on the spec sheet for your accuracy statement.....

Brad, we are not speaking about error of calibrated-uncalibrated sensors...
here we have David's (with your calibrated sensor) and Craig's (without your calibrated sensor) meters and have same values.... but i think this is OT in this thread....


but difference in real or imaginative formula to calculate gauss from Vout of sensor...

please reply to this: do you need a calibrated meter to say that all measured with mrcandy imaginative formula is wrong?

Vmax= Vnull - Vlim
Bmax is the limit where sensor shuts.
Vmax is maximal value that determines 840gauss(Bmax)
ΔV= Vmax - Vout
Bgauss=Bmax*ΔV/Vmax

bye

[RedHouse]

Brad, we are not speaking about error of calibrated-uncalibrated sensors...
here we have David's (with your calibrated sensor) and Craig's (without your calibrated sensor) meters and have same values.... but i think this is OT in this thread....

No, read again.

Not "same" but "similar", these are not the same thing.
(probably a language translation issue)

But I was not speaking to you, I was speaking to David(S) post, and his recollection of history, not OT at all.

[-Elepro-]

ok i suspect you are angry with me too.... and you do not want to reply to my previous question to you about mrcandy formula....

but just for clarity:

On Saturday I went up to Wolfe's place and we did the deed and found the Elepro kit measuring a bit off ...but... calibration was able to bring it in-line with Wolfe's meter. The next day I went over to Lollars place and did the same thing, and since the previous day's calibration, the readings were accurate with Jason's meter.

you forgot to say you move calibration from 1.3 to 1.36...... then error was 4.6% on uncalibrated meter (i think good ) ...( but i guess how you can measure exaclty same point of a magnet...)

ok... now you will say that datasheet says 23% worst case (even if you never found a sensor worse than 10%)... and you will not reply about mrcandy formula too.... but it's not a problem ...

bye bye

[RedHouse]

ok i suspect you are angry with me too.... and you do not want to reply to my previous question to you about mrcandy formula....

Don't care.

I was addressing David S not you, move on.

[big_teee]

The More Things Change, the More Things Remain the Same!
Is it Night or Day Outside, a New Topic to Argue About!
B_T

[RedHouse]

The More Things Change, the More Things Remain the Same!
Is it Night or Day Outside, a New Topic to Argue About!
B_T

Consider the source.

[big_teee]

I do notice all the arguing is mainly with the people using the forum for profit and personal gain.
I thought this place was to meet, discuss, and share Ideas.
Not to list PayPal accounts, and try to use it to List and Sell things.
Then again, maybe I live in my own Naive Sheltered Little World!
But, I like it that way!
B_T