A simple, battery-powered, pocket-sized, open-source parts counter for 8-mm cut tape and partial reels

Jul 06, 2023

Project update 10 of 10

Your BeanCounter is On the Way!

by Nick P

Packing the Boxes

I’m pleased to finally announce the BeanCounters have been built, programmed, and packaged!

As you’re reading this, I’m packing the box to Mouser for distribution and arranging for it to be shipped. It will take a few weeks for those units to make it through Mouser’s system and then they’ll be on their way to you!

This is a great time to verify your shipping address is correct at to ensure that your BeanCounter arrives without issue.

I appreciate your patience as I’ve navigated various unexpected delays and I apologize for not communicating more regularly as the shipping dates changed. So what was I so busy with?

Final Firmware and Self-Test

A small problem I found with the BeanCounter firmware during testing is that as the battery drained, the system voltage could drop below the forward voltage of the photointerrupter LEDs without affecting the operation of the microcontroller. This resulted in a state (around 2 VDC) where the BeanCounter would miscount and act erratically. Initially, I attempted to fix this error with the microcontroller’s brown-out detection feature, but that would have significantly shortened the useful battery life. Instead, I programmed a small self-test which runs at power-on and any time the count is reset. This self-test runs in about half a second and directly tests the photointerrupter functionality by flashing the LEDs and looking for correlating changes in the phototransistors. If the test fails, the user is warned with a message, BAT ERR, on the screen.

User Manuals

I was able to lay out a reasonable one-page user manual to get packed in with the BeanCounter. In order to make it useful for the largest number of people, the manual will be included in both English and German. I hired a translator to draft the original English-to-German translation of the manual, but due to the technical nature of the writing this translation was imperfect. A huge danke to all of my German friends and colleagues who helped tweak the translation. The manuals were printed front and back—English on one side and German on the other—on my laser printer and then individually hand-folded. I’m quite pleased with the final design and layout of the documentation.


The packaging I landed on for the BeanCounter is very much inspired by a brand of frozen breakfast burritos I used to eat. It may seem odd to wrap a manufacturing tool into a little paper bundle, but it meets all of the criteria that I set out for myself. The packaging contains very little plastic, essentially just the laminated sticker used for the label. Unlike a poly bag, it also provides some minor padding thanks to the use of textured kraft paper. Finally, it creates minimal waste but still gives you the experience of unboxing (or unwrapping?) when you receive it.

Thanks for reading and thank you again for your patience and support. I’m off to pack a box with a truly neurotic amount of bubble wrap.



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