Hello,
I'm searching for magnetic field sensor with detection radius 2m, the closer you get to it the bigger the value. Can somebody please explain how to calculate range, there is probably a formula that calculates the rage from frequency...
Hello,
I'm searching for magnetic field sensor with detection radius 2m, the closer you get to it the bigger the value. Can somebody please explain how to calculate range, there is probably a formula that calculates the rage from frequency...
A magnetometer detects magnetic fields, which are all around you, all the time. So "detection radius" is not a meaningful concept.
there is probably a formula that calculates the rage from frequency.
What frequency, and of what?
tomi12345:
Hello,I'm searching for magnetic field sensor with detection radius 2m, the closer you get to it the bigger the value. Can somebody please explain how to calculate range, there is probably a formula that calculates the rage from frequency...
MC95 Magnetic field sensor
What is wrong with the one you linked to? Of course, to use it with an Arduino you need to amplify the output signal.
Paul
I haven't used this kind of sensor so I don't know how it behaves. For my project I need a sensor (any recommendations) to detect magnetic field. Lets say I'm traveling at 50mph and I have sensor on me, when I come close to an object (magnet) within 2m the sensor starts picking up magnetic field, the closer you come to it the bigger the value. I need this to see how close/when was I the closest to it when I passed by it.
tomi12345:
Hello,I'm searching for magnetic field sensor with detection radius 2m, the closer you get to it the bigger the value. Can somebody please explain how to calculate range, there is probably a formula that calculates the rage from frequency...
MC95 Magnetic field sensor
That's a magnetic loop antenna detector, detecting magnetic component (B-field) of em-radiation, both near-field
and far-field low frequency radiation. Far field decays as 1/r^2, near field is 1/r^3. Since the receiver cannot
discriminate near from far field, and since the transmitted power is unknown there is no formula for range. It
just tells you the B-field component at the point of measurement.
It won't detect steady magnetic fields at all, you are confusing this with a magnetometer.
Magnetic fields have the same 1/r^3 law as near-field, so range is very limited unless the magnet is physically large. Once far enough from a magnet the field will be masked by the earth's field and variations in the earth's field due to magnetic materials in the vicinity. Detecting a small magnet from 2m isn't viable.
2m is a long distance for a magnet, due to the 1/r3 rule. You need a mighty strong magnet to be detectable and by "detectable" I mean "stronger than the Earth's magnetic field."
Can you use something other than magnetism?
Yes a strong magnet will interfere with Arduino so I dropped that idea. Now I'm thinking going RFID.
So after googling RFID solution I found out it is unsuitable for measuring distances with any acceptable accuracy. I'm trying to find a way to see how close/when was I the closest to an object. Does anybody have an idea?
I was mentioning magnet and rfid because it doesn't need powering source, all the equipment will be on me. Passive RFID tags would be powered when I come close to a "reading-range" so as magnet, but that will not work for me.
So what you're actually looking for is a distance sensor?
Lots of options for that - tell us more on what you actually try to measure (distances, objects involved, size of the objects, possible obstacles, the environment it's used in, etc).
Yes some sort of distance sensor. Lets say I'm traveling at 50mph and I have sensor and on me, when I come close to an object within 2m the sensor starts picking up signal, the closer you come to it the bigger the value (lets say I'm trying to do a perfect cornering in winter sports). It doesn't have to be measured in meters or centimeters (but why not if its doable). I need this to see how close/when was I the closest to it when I passed by it.
I was thinking of using radar or a sonar to detect that but snow might get in the way by covering the sensor.
Radar and sonar will go through a light dusting of snow. Optical sensors will be blocked easily.
Sonar is relatively slow, maybe too slow to have a good resolution for a 50 mph passage - that's some 22 m/s. If you want a sonar sensor to sense you up to 3m distance you can in theory do 50 measurements a second, meaning you move 44 cm between two measurements. Very good chance to miss the closest point!
For you to get a good idea when/how far you were at the closest point I'd say you should aim to measure your position at some 10 cm intervals - over 200 measurements a second. LiDAR and radar are the only two technologies that I can think of that can do this. The snow will easily block a LiDAR sensor, radar should go right through.
Another option would be a high speed camera mounted above the turning point (or hanging from a drone above it).
Hope you have a healthy budget as it's not going to be cheap, though in the latter case you can save quite some money by using a tree as turning point and hanging it off one of the branches. That immediately gives you a nice extra incentive to be accurate in your turns