3d Magnetic field in real time
I want to measure the three dimensional magnetic field in some limited space. (Oil and iron particles cannot be used).
The way I think it can be done is building a device for measuring magnetic field (vectorized) and position (3d) in real-time. I mean, a device that has a "point" (lets call it "pencil") that "reads" current relative magnetic field in 3D (that is, in 3 directions, X,Y and Z) AND the relative position of that point. For every moment, the device should generate 6 numbers: x, y and z of both position and magnetic field.
The device also should be connected to a computer and I will develop the drivers in order to read all data.
I want to build it myself, by buying all needed components. For magnetic field reading I think I can use 3 Hall sensors (positioned in three orthogonal directions). Do they interfere with each other? Im not sure, but I would need to buy also 3 multimeters? do you have an idea of how to avoid that? The problem is that I will have to open them, and try to figure out circuits, connect display input to an USB cable... really hard thing I think. I have no advanced tools or devices in my house-lab (oscilloscope, nothing like that).
For reading 3D position of the "pencil", I have no idea how to do that. I need help and ideas here.
So, after building that device I have to move the "pencil" through the room (trying to keep rotation of the detector unchanged), and I will have all the data of magnetic field in the computer....
Am I Mad?
Thanks a lot people!
Have a nice Day.
Juan from Argentina
There are projects to make an electronic compass using 1 or 2 hall sensors. These can be a guide.
The sensor looks about like a transistor. You feed 5V across the supply pins. (I guess there's a 3.3V version as well).
The output terminal ranges between 0 and 5. Absence of any magnetic field produces 2.5. Most likely you will need to amplify the signal.
Consider that you'll always have earth's magnetic field in the background. On one hand it will help you test your project, on the other hand it will interfere with detecting weak manmade magnetic fields.
You would be far better to get a PC based data collection system with at least 3 analogue input channels. I've not looked what is around now, but I expect you can get some pretty inexpensive things based on USB. Once you have the data in a computer, you can start doing calculations with it, such as looking at the magnitude and direction. You wont be able to do that too easily with 3 DVMs!
Dave