Adafruit recommends use of a high strength magnet with the Hall sensor you linked, so it is very unlikely to be able to detect the magnetic field from a single current-carrying wire.
That device is a hall switch, no use at all. You need a linear hall sensor (output
voltage proportional to magnetic flux density). In principle its doable, but
you can also just use a commercial clamp-on CT - probably not much more than
buying a split ferrite toroid.
Yes, those components look OK - the problem may be creating a gap for the hall device,
cutting ferrite is difficult (diamond wheel will do it).
Or you can add the hall sensor on one side and a piece of iron on the other.
You also need to calibrate it - the mechanical dimension of the gap the hall
sensor fits in is crucial as the magnetic flux depends on it and the current.
A CT has the advantage that the magnetic circuit is not crucial and there is
no gap to worry about.
MarkT:
Yes, those components look OK - the problem may be creating a gap for the hall device,
cutting ferrite is difficult (diamond wheel will do it).
Or you can add the hall sensor on one side and a piece of iron on the other.
I'm not sure if I picture it right: I put the ferrite around the electric cable, on one side I put the Hall sensor, on the other a piece of iron in something wich may looks like this:
Am I right ?
You also need to calibrate it - the mechanical dimension of the gap the hall
sensor fits in is crucial as the magnetic flux depends on it and the current.
Do you have any links about the "rules" of calculations involved here ?
A CT has the advantage that the magnetic circuit is not crucial and there is
no gap to worry about.
No! The hall sensor has to be in the magnetic circuit(*), in one of the gaps between
the toriods. The other gap should be bridged with iron or ferrite to continue
the magnetic circuit. But its not a great scheme unless the mechanical positioning
is the same everytime you clamp it on, the exact spacing of the gap in the magnetic
field dominates the behaviour (gaps always dominate magnetic circuits).
(*) The flux flows round the toroid.
If you don't need to clamp-on, you can take a one-piece ferrite toriod and cut
a slot through it with a diamond wheel to take the sensor - the result has
fixed dimensions and can be calibrated. But you have to thread the wire
through the toroid.
Again, a small clamp CT from a power monitor unit is a simpler option, easy to
find these days as extra probes are often sold separately.
