That would be fine. A 595 for the rows, and 8 arduino inputs for the columns (with the internal pullup resistors turned on).
As for price:
[u]For the Matrix method[/u]
Diodes are about 5p each, and the 74hc595 is around 41p,
64*5p + 41p = £3.60
[u]For the parallel to serial method[/u]
Resistors are about 0.25p each, 74hc165s are around 31p each.
8*31p + 64*0.25p = £2.64
As for soldering, that is really up to you.
[u]Disadvantages of 2nd:[/u]
- Have to solder 8 IC sockets rather than 1.
- Have to solder 64 resistors.
- You have 65 wires coming off the chess board rather than 17. Though if you put the electronics under the chess board this isn't an issue
- Dont have to solder 64 diodes
- Dont have to solder the reed switches into a matrix of rows and columns. Instead all reed switches go to an input, and to GND.
Its neck and neck really. The only real difference is that the matrix uses 9 pins, while the parallel to serial method uses 3.
Either is fine