Quantity   Component name
1 × Old secretary desk from ebay
30 × Sheets of 5 mm plywood
20 × Diverse precut wood boards from the hardware store
6 × Spray cans of white chalk paint
100 × Relay SPDT SRA-05VDC-CL - Ningbo songle relay co.,ltd
100 × Relay SPDT (slightly bigger) SRD-05VDC-SL-C - Ningbo songle relay co.,ltd
500 × Miniature switch SPDT - for ROM
500 × Condensator 25V - 220 µF
1 × lots and lots of wire