Gauss Meter

[oppress3d]

Hello everyone
Could you please help me to find a gauss meter? I'm living in germany and it look like that they are all super expansive here...

I could find only those from china:

WT10A LCD Tesla Meter Gaussmeter
https://bit.ly/36SLLXv

Digital Gauss Meter
https://bit.ly/3lPVsdl

[ElectroWinder]

They are expensive for what they are - I looked on aliexpress a few days ago, and was surprised at the cost, even direct from China

They all use a hall effect component that is cheap, so you could make your own - that's what I'm going to do - do a web search for "hall effect diy gauss meter" for lots of info and plans

[JayGunn]

I just got my home made gauss meter re-housed and tried it out today. I wanted to ask the experts here a few questions about technique for making the measurements, and I see that you two want to create your own meter. So I'll explain how I made it, although you have to adapt the concept to whatever Hall effects sensor you can get. I use an Allegro A1302, which is a tiny 3-pin IC. Its inputs are +5VDC and Gnd. It output is half the input, so it is 2.5V. This output voltage varies up or down according to the strength of any DC magnetic field it is in the presence of. For this particular chip the output drops or rises by 2.5mV (millivolt) for each gauss it detects. So if its output drops to 1.5V or rises to 3.5V that's a change of 1000 mV, which corresponds to 2500 gauss.

WARNING: I am getting what seem like quite high readings on the 5 or 6 pickups I have checked which makes me wonder if I have an error in my interpretation or method. I haven't used this device in several years at least.

Basically you need:

-- a 9v battery (for an A1302 -> 7805) or some DC power source
-- a push button (momentary contact, not latching) that supplies the 9V to the circuit
-- A 7805 voltage regulator chip or some other way to feed the Hall sensor the voltage it expects. Naturally the 7805 puts out 5 volts as the name suggests.
-- a pair of terminals to which you can connect a multimeter to read the output voltage of the Hall sensor OR (the way I just implemented it) a cheap eBay LED DC voltmeter. This is the type I use (for a number of projects):

https://www.amazon.com/dp/B00YALUXH0...xpY2s9dHJ1ZQ==

Extra details:
-- put a capacitor from the 9V supply (or whatever you have) to ground at the input of the 7805 (or whatever regulator you need). anything from 1uF to 10uF should be fine
-- put a capacitor from the 5V output (in my case--the input to the Hall sensor) to ground. anything around 0.1uF should be good

Since the LED voltmeter uses about 30mA, you want to connect its power supply wire after the momentary contact push button so it is not on all the time. You don't want your voltage regulator getting hot, so having the voltmeter turn on only when you are making a measurement keeps the heat a non-issue.

Please let me know what you find that can substitute for the A1302. What if mine fails? My inquiring mind needs to know. Too bad it is discontinued! The main concern is that the Hall effects sensor should be linear so you don't need to do complex calculations to get the magnet strength reading.

Hope this helps! Now I'm going to do a search in the forum to see is my question(s) have already been answered.

John

[Possum]

The gold standard for DC gaussmeters is the AlphaLab DC magnetometer. There's one on Ebay now for $100, but has no Hall probe to go with it. Alphalab could make you one to fit it, but they charge pretty high for simple stuff like that. I have two of them, one as a backup I bought used on Ebay for real cheap, a stroke of luck. They were like $500 new. The ones they sell now, look different but same thing really. Some guy years ago made copies of them, but I think they shut him down.

[eschertron]

WARNING: I am getting what seem like quite high readings on the 5 or 6 pickups I have checked which makes me wonder if I have an error in my interpretation or method. I haven't used this device in several years at least.

I was playing around with the Gaussmeter on my phone (used to detect magnetic north and whatnot) and one day thought to read a pickup field with it. All I can say about that is Don't. The field strength coming from pickups is indeed VERY HIGH, larger than that from any (or many) natural phenomenon. I suspect your readings are correct.


That little experiment broke the sensor on the phone; never worked again for compass work.

[Helmholtz]

If you read higher than 1300G in the middle of strat PU A5 poles, the calibration is off. Typical values are 800G to 1100G when fully magnetized.

[MzR]

i use diy gaussmeter https://www.youtube.com/watch?v=FnAa6KMZgeY