DIY Ribbon Mic?

Little side project I'm working on, a diy ribbon microphone. The parts required are really bog simple, magnets, aluminum foil and a transformer. The foil is in the micron scale though.... difficult to source. But here's the magnets, N42 neodymium.

For a start I'll be designing the housing for a short ribbon length, about 1 inch, vs the longer lengths commercially available.