In order to get a handle on my DigiKey SMT part cruft without counting parts one by one I built this simple tool to count parts in SMT reels. It's a simple 3D-printed sensor block with a break-beam sensor that I can easily slide the SMT part tape through which is hooked up to a simple Arduino shield with two buttons and a 3 digit 7-seg display for displaying the parts count. The right button resets the count and the left button sets the number of parts per hole on the tape.
I was lazy hooking up the 7-segs and put a current-limiting resistor per digit on the low-side, so the brightness changes depending on how many segments are lit up. Still legible and saved me having to add MOSFETs or something to sink the current.
Hi! Do you have an .STL of the 3D printed adapter, by any chance?