Perhaps this is more of a mechanical engineering question than electrical engineering. I spent tons of time on it and came up with solutions that sorta work, but do not scale at all. I was hoping someone can help us with this predicament.
I need to find the easiest and most reliable way to make two surfaces conductive when pressed against one another. Why? I have Lego pieces of the large variety (2" x 2"ish) that are modified internally to have wires connected to opposite faces . The right face is connected internally to the left face and the front face is connected internally to the back face via fine wires. The internal connection forms a '+' like pattern, if that makes any sense. This was accomplished by drilling fine holes through the 4 sides of each cuboid and threading wires through them. The idea is for children to place such Legos adjacent to one another on a Lego surface and form various electrical tracks triggering lights, fans to turn on...etc. I need each two Lego pieces that are touching to be conductive. For example, if I place 10 Legos in a single row, then a current could flow from part 1 all the way to part 10 passing through all the pieces in between.
The struggle we I am facing is in the choice of material to use on the outside surfaces to make the faces conductive. So far, I tried using small pieces of Copper conductive tape and even Nickel battery strips. They "do work" but they peel off really quickly and fail constantly. I also experimented with neodymium magnets, but they seemed barely conductive not to forget how lethal they are if swallowed, especially by children. I combed Digikey and other sites for some sort of spring loaded contacts. The only parts that showed promise are pretty pricey at more than $4 each. Remember, I need 4 per piece. Do you any suggestions that you think could work?