Sven
Obviously you could use reed switches (god knows how many I have replaced in my Conchess boards).
But I wanted to keep everything very cheap and reed switches aren't cheap compared to a roll of self adhesive aluminium tape that costs only £2.50 and for that you could make 20+ sensory boards.
I wanted to make something completely different, something unique, something other computer chess friends might find easy to make.
I hope by producing these DIY chess boards it will encourage other people to have a go now that the long winter nights are fast approaching.
Best Wishes
Bryan