Using Magnets as the Blades in a Soapbar Rail HB?

[The Fool]

Has anyone tried a gauss meter app? I have an HTC Android powered phone that I downloaded a free gauss meter for. It gives readings right in the posted range of humbucker bar mags. Curious if anyone with real meter had compared the two.

[SonnyW]

Would this be a good one?

DC Gaussmeter Model GM1-ST

I have the older version of that meter (GM-1) and it has been a great help.

[FunkyKikuchiyo]

Now that I see the prices on them, I feel bad about saying you need one so quickly. My main point was that you'd be in uncharted waters and it would be something to pay close attention to. Perhaps that investment wouldn't be worth it...

I knew how pricy they were (I was going to buy one for myself a while back) but I evidently forgot.

[SonnyW]

Has anyone tried a gauss meter app? I have an HTC Android powered phone that I downloaded a free gauss meter for. It gives readings right in the posted range of humbucker bar mags. Curious if anyone with real meter had compared the two.

I haven't compared the two, but I did google around to look at the available apps. An EMF meter that reads AC fields is different than the meter I use which reads DC fields. To be useful to me it would need a hall effect probe, so I could touch the face of the magnet.

[David King]

A DMM and a hall sensor will get you in the door for a whole lots less than any off the shelf Gauss meter. You could probably get effective measurements for less than $25 with an Alegro sensor off ebay and a Harbor freight DMM. Elepro's kits came in at around $90 and took about an hour to assemble. They were far more sophisticated than most "Pro" gauss meters for about 1/3 the price.
Personally I don't think a gauss meter is necessary to make a great sounding pickup. It's too easy to get hung up on gismos when you can hear all you need to hear with your own ears.

[The Fool]

Thanks, Sunny. Please forgive my impeccable understanding of electronics, but is there any reason the AC readings of this app wouldn't be good enough? At least as a reference from magnet to magnet. We have all seen the nifty gadget Duncan uses. Would it be any less precise than that?

[SonnyW]

Thanks, Sunny. Please forgive my impeccable understanding of electronics, but is there any reason the AC readings of this app wouldn't be good enough? At least as a reference from magnet to magnet. We have all seen the nifty gadget Duncan uses. Would it be any less precise than that?

I am not an expert on this by any means, but nevertheless here is my take on it. The magnets that you are trying to measure the charge of have a steady permanent field, in other words a DC field. The type of meter that most of the apps I saw when I looked online were trying to duplicate is an AC EMF meter. Those meters measure pulsating magnetic fields like mains hum. The units are different too. Most of them measure in microTeslas. Take a look at the description one of the Trifield meters that I think the app is trying to imitate. A microTesla = .01 Gauss, so the strength of a typical alnico rod used for a strat pickup, measured in microteslas would be 60,000 microTeslas to 100,000 or more. I don't think the meter app is going to register that high, and it is looking to measure changes in the strength of the field more than the absolute strength of the field. To me the use of that app is to measure the EMF field of microwave ovens and solar storms, not static fields from magnets.

The handy gadget that Duncan uses is a R.B. Annis Magnetometer. It works by measuring the field a small but constant distance from the surface of the magnet's pole. So when pickup makers report measurements made with the R.B. Annis meter the same strat magnet might read 40 to 50 gauss, which is right but it is the strength at some distance from the pole itself.

This is not to say that you couldn't try it out and see if it will give you some useful readings, for example measuring a fully charged alnico 2 rod and a fully charged similar alnico 5 rod. The alnico 5 rod should be a lot bigger reading as much as double. I would be interested to see the result of that trial.

[David Schwab]

The handy gadget that Duncan uses is a R.B. Annis Magnetometer. It works by measuring the field a small but constant distance from the surface of the magnet's pole. So when pickup makers report measurements made with the R.B. Annis meter the same strat magnet might read 40 to 50 gauss, which is right but it is the strength at some distance from the pole itself.

These things are useless. It goes from -50-0-+50, so if you place it on a pickup it will likely read "50". But "50" what? If it's gauss that doesn't help you, since something like a Strat pickup might read 600+ gauss. So that's not a direct reading, but some kind of arbitrary scale.

[peskywinnets]

If you already own a DVM, then a gaussmeter need not cost more than about $3.....

1 x 9V battery
1 x 5V regulator
1 x 10uf caps
1 x Allegro A1302 hall effect transistor.

one leg of the transistor to ground, the other leg to 5V....the final leg is the output to a DVM.

place the hall effect tranny on top of a magnet & the voltage as seen on the DVM will deviate....either more towards 0V (south magnet detected) or more towards 5V (north magnet detected)

You then just divide the deviation in millivolts by 1.3, therefore 3.5V observed on DVM....deviation = 1000mV 1000/1.3 = 769.2 Gauss.

[SonnyW]

These things are useless. It goes from -50-0-+50, so if you place it on a pickup it will likely read "50". But "50" what? If it's gauss that doesn't help you, since something like a Strat pickup might read 600+ gauss. So that's not a direct reading, but some kind of arbitrary scale.

I wasn't too clear on it, I meant to suggest trying the free app. I wouldn't suggest getting a Magnetometer because of just what you mentioned. I do think the Annis meters read in gauss, but just at such a distance from the pole to be a lot less useful than a hall effect probe.

Also, David to one of your other posts, I agree that you really don't need any kind of gaussmeter to make good pickups, but you do need good ears and a mule guitar or two.

[big_teee]

If you already own a DVM, then a gaussmeter need not cost more than about $3.....

1 x 9V battery
1 x 5V regulator
1 x 10uf caps
1 x Allegro A1302 hall effect transistor.

one leg of the transistor to ground, the other leg to 5V....the final leg is the output to a DVM.

place the hall effect tranny on top of a magnet & the voltage as seen on the DVM will deviate....either more towards 0V (south magnet detected) or more towards 5V (north magnet detected)

You then just divide the deviation in millivolts by 1.3, therefore 3.5V observed on DVM....deviation = 1000mV 1000/1.3 = 769.2 Gauss.

Is there a white paper, or schematic for this.
I hear this repeated, Could someone draw it up and put it on here?
If it is already out, could someone post the link?
T

[peskywinnets]

Is there a white paper, or schematic for this.
I hear this repeated, Could someone draw it up and put it on here?
If it is already out, could someone post the link?
T

It really is as simple as I've described, but there are pages aplenty which give more detail...

Build your own Gaussmeter

I designed/built my own slightly more elaborate gaussmeter just the other day....instead of feeding the hall tranny output to a dvm I feed it into a PIC AtoD pin... the PIC then does the calculation & spits out the gauss data serially to my PC (the PIC also lights up an LED red or green depending on the polarirty)....total cost was about $3.