>>11682248take a wire. solid core copper wire. pick a thick ish gauge wire . .8 mm 20 awg gauge or larger. this is important because you want the wire to hold its shape. now make a single weak inductor thats air core by making a coil around a pen or pencil with maybe 10 wraps. now with another piece of the same wire make another 10 wrap inductor but this time within 3/4 of a inch wrap another inductor the opposite direction
the first coil you made will make a magnetic field when you give it sufficient current. a single 3.7 lithium ion cell will probably do though 18650s come in a million flavors of amperage so anything from 1 amp top 30 could go through the wire. but it should be able to attract or repel a permanent magnet thats strong like a neodynium magnet or piece of steel thats small
the second will not make a observable magnetic field. when the first field raises and the current continues its negated by the second field as it raises. the first inductor would have north on 1 side and south on the other but the second inductor you made was a pair of inductors made from a single wire. it has the same north or south polarity on the joining section and the lines of force that congregate to make the magnetic field through a inductors coil do not like going in another direction to make another field that is opposing to the first so it implodes and neither reraise after that unless you cut the power and do it again
you need a hal effect sensor to detect the field of the 2 inductor 1 wire inductor as long as they are close enough this will always happen if the first coil isnt wrapped the same direction as the second coil
