This project requires a high impedance voltmeter to read. As I am a hobbyist, I did not understand what is suggested in the post below:
And so, I couldn't advance on how to make it work. Is there a way for someone with little knowledge like me to make this project work? Could someone help me with how to do this? I am very grateful in advance for any help.
I'm sorry about my english... it's a work in progress.
It will detect time varying electric fields, but you don't need the diodes or a capacitor. Simply attach a short length of wire (antenna) to an analog pin, run a tiny program that reads the analog input and prints the data to the serial monitor, and wave your hand near the antenna to see the effect.
Warning, though: electrostatic discharges can destroy the analog input pin.
Dear @jremington , so, how do you suggest doing a milligauss detection with Arduino? This, if you understand that it is possible. Thank you very much for your time and attention.
@jremington Thanks again for your kind attention and help. Do you believe that with this 3-axis magnetometer I will get reliable resolution between 0 and 3 milliGaus? Thank you very much.
Hi, @jremington thanks for your question. I'm interested in this range because I read in an article that the magnetic fields generated by the human body are exactly in this range. Well, I'm a high school philosophy teacher and I want to know if this statement is true. So I want to reproduce the tests and find the variations myself. If they even exist.
All electrical currents generate magnetic fields, so of course the short-lived electrical nerve impulses in the human body do so. But the generated magnetic fields would also be impulsive and equally short lived.
The data sheet for the LIS3MDL magnetometer specifies the sensor noise level as about +/- 3 to 4 mGauss (at the +/- 12 Gauss sensitivity setting), so it will not be straightforward to measure fields of 0-3 mGauss.
Magnetic fields decay as the inverse square of the distance. So unless wrap a coil of wire directly around a nerve axon, the field outside the body would probably best be measured in femtogauss. Or, some unit of measurement so small that you would have to look it up.
Also nerve impulses do not travel like charges in a conductor. It is a chain of connected cells, reproducing the polarization as it passes from cell to cell. Like nodes in a computer network. So the extremely miniscule magnetic field is additionally localized by this mechanism.
If you want help duplicating a demonstration or experiment, please provide links to that experiment.
In addition to the above comments, I mentioned the Earth's magnetic field for a reason. The 0-3 mG would be in a background over two orders of magnitude larger.
Although the Earth's field can be canceled, it takes quite a large apparatus. Look up Helmholtz coils for one option.
If you want to experiment with mag field detection perhaps the simplest way is to use a sensing coil, and a high impedance voltmeter. You could try THIS CIRCUIT with a few turns of wire to make a sensing loop of about 4 inch diameter, and a LARGE value resistor (say 100M) across the einputs.
About the component, I've also been looking for a triaxial magnetometer. The problem is really the resolution. The best I could find was the model suggested by our friend @jremington with a resolution of +/- 4 milligaus, however, noise is another problem to consider in this model (according to the datasheet). Another problem is the very high cost of importing to my country: US$ 82.00.
Which is a lot for a teacher's salary around here, practically making it impossible for me to go in that direction.
Dear @jremington , my first idea about this was to carry out the experiment in a box completely lined internally with copper tape, with this coating connected to the Arduino's GND.
Only one hole so a hand would be present. With this (a Faraday cage) I was hoping to isolate any external electromagnetic fields.
Once again, thank you so much for your time and kind support.
Dear @anon57585045, if the premise is correct, the human electromagnetic field is itself an ELF. Please let me know if I misunderstood your kind post and thank you for your time and attention.
Dear @anon57585045 , if I understand your point correctly not only the claim but also the reproducibility of the measurement of the electromagnetic field of the human body are extremely difficult to obtain outside an extremely specialized laboratory and under non-invasive conditions.
However, these difficulties have made the challenge of measuring this field even more interesting. Perhaps, and please correct me if I'm wrongly assuming, the best place to get a non-invasive reading is the head. Still, at the moment, I have no ideas on how to proceed.
As for the article I read (presented in class by a student), it was simply a statement, without sources. Typical, in my understanding, of pseudoscience. And this is precisely the point I want to demonstrate: science takes work, it requires method, attention and careful documentation. It must allow reproducibility and falsifiability.
I want to demonstrate that we cannot accept information without sources, and that even so, refuting a statement takes work, but it is, in my understanding, the only way to really value and disseminate science.
I know that the burden of proof is on the person making the claim. However, as a philosophy professor, I want to demonstrate that, in the fight against disinformation, a passive attitude is not allowed. In my view, we must do everything in our power to demonstrate that science is not done with "guess".
Thanks again for your time, attention and kind support.
"The simple circuit is used to illustrate the method of measuring the amount of AC magnetic and electric fields "
The text makes amusing reading.
A conversion exists in changing the value from volts to gauss, wherein the millivolts is divided by 4 to attain a value in milligauss.
..
The sensor at the tip could be made at the end of an 8-wire cable having a length of 4 feet or a variety of distances. Since the cable points in the same direction as the component of the field that is being detected, the sensor can be termed as axial. It can be made of high sensitivity material for high precision magnetic field measurement, a copper piping cut in short stub, or a piece of wire used for fencing. Any material can be utilized for as long as it can make good hand contact.
You may find that such a refutation has certain limits. Suppose you complete your experiment, and it detects no magnetic fields whatsoever. You can be told, "but... you just didn't do it correctly". Here, you are using hobby parts too. A failed experiment isn't proof of anything, by itself.
I deeply and completely agree with you. However, my primary aim is to awaken critical, active and scientific thinking (as far as possible) in my students. If, in your experience, you have any recommendations or advice in this regard, I would be immensely grateful to hear from you.
I agree that the text is "fun" in many places (not on all sites). But I clung to the circuit as a possible "lifeline" for what I intended to measure (and with what resources).
I also understand that converting millivolts to milligaus by just dividing the first by 4 is a gross misconception. I decided to try anyway because the components presented are so cheap and so easy to assemble. With the exception, of course, of the high impedance voltmeter.
With all this I decided to ask for help in order to try to get a resolution of 1 milligauss with the help of an Arduino.
If this is possible and feasible, I will be satisfied.
Thank you very much for your precious observations, for your time and kind attention.
