Recently, Adafruit posted about the calcu-pen, a retro piece of technology.

Maker Joey Castillo really liked the concept and decided to make a more modern equivalent. He’s using a SAMD21 microcontroller and technology developed in prior projects like a crowdfunded watch. Custom PCBs from Oshpark.

Joey says:

Y’all.Great success. First off: the pen is a pen. No battery as of yet, but that’s not much weight; so far it feels balanced in the hand, and size-wise feels reasonably in line with other pens in my arsenal.

But second and more importantly: IT WORKS! And runs Python, because that’s another joy of using the SAM D21 for prototyping: CircuitPython always “just works”.

I just wrote a simple calculator app for the pen in CircuitPython and broke into the most over the top gigglefest. like I cannot explain why this is so hilarious to me but it’s been five minutes, I went to fetch my camera and I’m still laughing, it’s so ridiculous

See the results so far below and read the entire design process in this Twitter Thread.