I am thinking about manufacturing an interactive chessboard as a personal project. The circular pieces (resembling more or less poker chips in shape) would contain NFC tags, so it is possible for the devices hidden inside the board to collect information and update game state. Moreover, ideally, for convenience, I would want the pieces to also contain small magnets, so it is easier to move them. In this case, is it possible for the magnet and the NFC tag to not interfere with each other? If it is not, what alternative solutions can you see?
\$\begingroup\$ Why would having magnets in the pieces make it easier to move them? What size is the 'small' magnet, and what size are the tags? \$\endgroup\$– Bruce AbbottSep 10, 2020 at 5:38
\$\begingroup\$ People use magnetic chess sets as it lets you play chess on the go, on the moving train, car, in windy environments in the park, etc... and you won't have to worry about your chess pieces falling over/off. It also makes it harder to accidentally knock the pieces over. For some people with unsteady hands (old people, very young people, people with any kind of sickness, drunk people at a party), having the pieces "stick" to the board is also nice. \$\endgroup\$– Vince VargaJan 17 at 8:57
NFC relies on alternating magnetic (and electrical fields) changing 13560000 times per second.
A magnet represents a steady field, or at most one changing at the comparatively low rate at which you could physically move something.
There will be no interference in terms of the actual signals. And for reasonable magnetic field strengths, eg, things you could actually purchase and manually move, there will be no overloading of the components to the point where they misoperate.
It's not entirely certain however, that you'll have sufficient isolation between your various chessboard squares for NFC to uniquely detect position. It may work with care, but arrays of NFC antennas aren't quite the usual case, so there may be some engineering there, as well.
NFC tags are one way of doing it. Another would be to put an LC tank into the bottom of each piece, and tune each piece to a different frequency. The tank interrogation can be done by a "dirac delta" pulse applied to each board position in sequence. After pulsing the position, determine the frequency of the "answer", if any, and then move to the next position.