How to make the
simplest magnetometer ?
There are many types of magnetometers such
as Hall’s effect, fluxgate …etc.
But there is a disadvantage of that types
of magnetometers, they are always EXPENSIVE!
So we designed a simplest circuit to
measure the magnitude of magnetic flux, and it only cost $2 (USD)
Before we start to make the apparatus, we
have to know how it works.
We use the original definition of Faraday’s
law:
By this integral formula, we can figure out
the flux of a magnet.
But because of our coil is very small, and
the dt would be long, so the magnitude of eddy voltage would be very small.
So that we need to use an OP(operational
amplifier) circuit for two proposes:
1.
To amplifier the signal
2.
To integrate the voltage with
time
We used the integral circuit to amplify
100times and integrate the signals.
The OP integral circuit is driven by this
formula:
Next, we designed an 85-turns coil(diameter=
14mm; length= 23.8mm;dia. of wire 0.23mm) as a sensor to produce eddy voltage
to drive the apparatus.
Why we choose this size of coil? Because we
are going to use a voltage meter to measure the output signal, and we want to
show the voltage just as same as the value of ”Tesla”.
Following is our calculation of the coil
through the OP circuit and then produce voltage as same as the value of tesla.
We can know
It is the complete circuit that we used.
It is the simplest magnetometer
Use an oscilloscope to track the interaction of output voltage and a magnet.
Use a voltage meter to measure the magnitude of magnetic field of a magnet
V = Tesla
It is the magnetometer working.
Please subscribe, common, share.
This comment has been removed by the author.
ReplyDelete0.23mm x 85 turns give me 19.55 mm long.
ReplyDeleteSo maybe you left some space to obtain 23.8 mm
The total wire length is 3.73 mts.
ReplyDeletewith a p=0.0171 ohm mm^2/m
the coil resistance give me
R=l*p/transversal_area
R=1.53 ohms but you has 0.45 ohms
Also I found 0.45 ohms in some table wire awg But I lost the place. So I am no sure if 0.45 is ok.
A tesla is a big unit. So is hard to detect by example the earth magnetic field. So is better use microtesla
ReplyDeleteHello Paco!
DeleteYes, you are right. A tesla is a big unit, but a strong magnet could produce about 0.8T. So I think it is suitable for detecting the magnetic field which is caused by a magnet.
Hi, Thanks for your effort. I have a little question: What volts and miliamper have the voltage source? Very thanks
ReplyDeletePablo
Hi Pablo,
DeleteI used 12.0V as a power supply but I'm not sure about the miliamper now(I'm abroad).
Is it possible to give us specs for a stronger magnetometer. Thanks
ReplyDeleteHow strong is your magnetic field ? But by the way, I'm abroad now so I cannot do experiment for you.
DeleteI not sure about the magnetic field but I am want to build a meter that can be used with a radius of approx 3 to 4 metres.
ReplyDeletecan we use this to measure the earth's magnetic field?
ReplyDeleteYes. But you need a bigger coil and you have to find out the direction of the magnetic field to adjust zero because the earth's magnetic field is always exist. So it would not be a good ideal. While the "Fluxgate magnetometers" is a good option to test the earth's magnetic field.
DeleteHi: THX for sharing. If Iwant to detect if I am far enough from a power substation/power lines, how should this be modified. THX in advance.
ReplyDeleteA power substation emits radio wave(electromagnetic wave) which is an alternative magnetic field and electric field. The net magnetic field is zero because + phase destruct - phase when a radio wave path through the coil of this apparatus. So this apparatus is not suitable detecting a radio wave.
DeleteHi buddy!
ReplyDeletewhat kind of resistor and capacitor do we use for this magnetometer?
thanks
I use a film capacitor and a carbon film resistor.
Deletedoes this setup work for dynamic sin() like magnetic field
ReplyDeleteThis comment has been removed by the author.
DeleteIf the frequency of your magnetic field source is strong enought and not higher than 10 Hz, you can see a sine wave on your ScopeMeter.
Deletecan i use it to determine the earth's magnetic field ?
ReplyDeletei want to know it's efficiency
thanks :D
You can change the amplifier to obtain a higher sensitivity then the earth's magnetic field could be detected. But there is a problem of this apparatus, due to it's an integrating circuit, the magnitude of the change of magnetic field is store as a "voltage" inside the capacitor. Therefore, a spontaneously voltage decay of a capacitor can influence your measurements. So, get a good quality capacitor is important for the experiment. Good luck~ :D
DeleteThank you for the diagram! For this setup to be more efficient it will need a better ground and shielding. What would you suggest? Perhaps an aluminum case or Faraday cage for shielding?
ReplyDeletei want to make a magneto meter , that can detect and measure the magnetism of a fero material object burried under ground , like rifle , iron pipe drum etc, and this video is not helping me, please email me , i will be much obliged , owaistoru@live.com
ReplyDeletecould you explain how you got the 0.45 ohms resistance and the length of the wire as 23.8 mm?
ReplyDelete