My goal is to build a chess board that can detect the movement of pieces on it. My current approach that I'm testing is to have a reed switch underneath each square and magnets attached to the bottom of each chess piece. I was inspired by this article.
However, in testing, what I'm finding is that when the magnet is dead center on the read switch, the switch is open, not closed! I found this article which was a very helpful overview of why this happens, and what happens in different configurations.
I've considered:
- Pole facing down - this has the switch off when the magnet is centered on the switch
- Thin bar magnet roughly equal to the diameter of the piece - this works pretty well given that the piece overlaps the center which gives a good enough margin for error; the problem is that it attracts/repels the other pieces next to it too strongly!
- Other approaches: RFID (looks more expensive, more complicated to set up, and hard to scan quickly enough), light sensors (requires drilling holes in the centers of the squares which I'd prefer to avoid)
However, I'm still at a loss - is there any clever way I'm missing to set this up so that a piece placed on a square triggers the reed switch, with a solid margin for error (I play a lot of blitz chess)?
