motorcycle speedo cable photo interrupter adapter

thingiverse

I've seen similar concepts before, but nothing that really caught my eye, so I decided to create my own adapter that screws onto a standard speedometer cable - just like the one where the stock speedometer would normally go. The cable fits perfectly onto it (12mm x 1mm thread) and the thickness of the plastic makes the adapter surprisingly strong. The hole is only 5mm, which is just enough for the cable to turn without making contact. Inside, a "chopper" disc with two slots fits snugly onto the end of the cable. This chopper disc runs through a photo interrupter that sends a signal to an Arduino (or whatever microcontroller you choose) where it's processed and somehow displayed on screen. Unfortunately, the chopper disc will have to be printed with supports due to its design. The whole unit is held together with three 3mm screws. Keep in mind that this is still a work in progress - I haven't actually acquired an actual photo interrupter yet. I had to rely on measurements from datasheets, but unfortunately not all of the information was available and had to be estimated based on what I could find.