Gaussmeter Kit Group-Buy

[defaced]

Similarly, if you align any piece of steel north/south and let it sit there, it will become magnetized. This is an issue with long term storage of pipe lengths because welding on magnetized steel is a nightmare. Google

I'll check out some other saw cut steel in the shop and see what I get. Forged steel is known to be magnetic, there are even people out there who specialize in degaussing the stuff: Magnetic Products and Services, Inc. (The Gaussbusters) - Home Page

[LtKojak]

If you align any piece of mild steel North-South and whack it with a hammer, it will become magnetized.

Is this what Possum does to magnetize his PAFs...?

[belwar]

Is this what Possum does to magnetize his PAFs...?

hehehe!

[defaced]

Alrighty, after some more work, I've got some context to what I'm playing with. Bad things start to happen to arcs above 60 gauss. Now I know Brad (RedHouse) calibrated these, but am I playing in a range where the error of the calibration could be effecting my readings significantly? If they're off by 5 gauss, that's no problem, off by 10, that's starting to make me nervous, off by 20 and I need to find a way to calibrate this beast.

Sawing these parts doesn't seem to be inducing magnetism. Machining might, but I'll have to wait until my big part gets back from the machine shop to see.

[-Elepro-]

A1302 sensor is not rigth for accurate measuring in that range.... least of all brad calibration....

you need a high sensitivity, factory calibrated sensor...

[defaced]

Could you suggest a sensor that would be accurate in that range and compatible with the PIC firmware?

[-Elepro-]

A1321LUA Calibrated Linear Hall-Effect Sensor

with this range would be about +- 450 gauss.... and it is factory calibrated

[defaced]

Excellent. So since this is calibrated from the factory, I just enter 5.000mv/G, which is the data sheet value, into the calibration for the PIC and I'm good to go?

[-Elepro-]

i think they send a datasheet for your specific sensor.... with the exact sesitivity value... (it will be 5.000 or 5.010 or 5.026.... ecc)

(it is not a special sensor... only it is a sensor measured before sell)

yes... enter value in calibration menu and you are good

[-Elepro-]

today i tested the ad22151....
as i supposed, for this application it doesn't need any external component (only the decoupling cap like the a1302).... it work very well and i have same value with both sensor....

but unfortunately the pole shown on display with ad22151 is reversed....
i'm sorry for this but as you can see there is an error in datasheets

POSITIVE B FIELD INTO TOP OF PACKAGE RESULTS IN A POSITIVE VOLTAGE RESPONSE

The presence of a south-polarity (+B) magnetic
field, perpendicular to the branded face of the device package,
increases the output voltage VOUT.....

so:

you can send me your PIC and i'll replace firmware with 2.2 version (where it is possible to store polarity operation for both sensor.... ) and i will return it (with not insured and not trackable economic air mail) for free....

or

you can wait and will have a discount for version 3 (new professional PCB with double side layer, double side soldermask and silkscreen + a small PCB for double side A1302/AD22151 probe.... + upgrades in firmware ..... average mode (read this ) + on board 4 tactile push button with power on/off-backlight on/off- sensor change - and all other functions... and on board usb connector for probe.... super easy to mount... only battery wire.... prototype picture soon...

bye

[spy]

Hey I got a little bit confused!

With the sensor that the Group buy got, the A1302, is the polarity correct?

[-Elepro-]

Hey I got a little bit confused!

With the sensor that the Group buy got, the A1302, is the polarity correct?

yes, with a1302 polarity is correct

[RedHouse]

...you can wait and will have a discount for version 3 (new professional PCB with double side layer, double side soldermask and silkscreen + a small PCB for double side A1302/AD22151 probe.... + upgrades in firmware ..... average mode (read this ) + on board 4 tactile push button with power on/off-backlight on/off- sensor change - and all other functions... and on board usb connector for probe.... super easy to mount... only battery wire.... prototype picture soon...

bye

How much will this new one be?

[-Elepro-]

i don't know now....but about 22 euro (PIC + professional PCB) for who has the old version 2

[spy]

Elepro, keep us updated!

[RedHouse]

i don't know now....but about 22 euro (PIC + professional PCB) for who has the old version 2

Seems a good price.

[David King]

Do we sacrifice the old gauss meter to build the new one or is it all new pics?

[DC Ross]

How about full kits for those of us that got to the party too late?

[-Elepro-]

Elepro, keep us updated!

yes.... i will post prototype picture and description soon...

Do we sacrifice the old gauss meter to build the new one or is it all new pics?

i'll send a new PIC and PCB.... then you can re-use old components or make a new one gaussmeter

How about full kits for those of us that got to the party too late?

i will arrange a list from MOUSER.... you will have to buy PCB and PIC from me and the other component from mouser.....

[-Elepro-]

about average mode of version3.0 descripted here:
if during measuring there's a pole change, would you prefer an automatic stop with error message displayed or counting in average with warning message in result?

[David King]

I think that could be a useful feature but it might also just get in the way if it keeps tripping on a particular type of magnet (I have no idea what sort of magnet would have this issue so it's probably a mute point.)

I think the "average" data collection is only going to be relevant to the long bar magnets and rails. Again, since the data collection is continuous and time is a function, you'll have to move the probe at a constant speed to get an "accurate" result. This isn't really a limitation but I think new folks will need to understand what the numbers mean and how to get repeatable results before they can benefit from this further refinement. FX; Scanning the full width of a Strat pickup with 6 poles in "Average mode" isn't going to give anyone a very useful data point.

I may be wrong about this, only way to know for sure is to try it out and see what results come out VS the peak hold method.

I'd rather see a head with multiple sensors in an array that averages all the outputs at once or gives you a map of the field strength. A miniature automated scanner could do this since at least the speed could be controlled. Again that's probably data-glut since who needs to know this more than once. All future magnets are likely to read more or less the same way and what can you do about it anyway?