I2C Paper Tape Reader is Now not What You Assume

We’re no longer moderately certain what drove the improvement of this undertaking, however [shapoco] has put in combination an intriguing software that reads I2C alerts(*16*) (Jap Twitter hyperlink) that have been published as black and white rectangles on paper tape. He wrote a program that prints an I2C byte flow onto strips containing the SCL and SDA sign patterns. As soon as published, you narrow the strips from the paper and glue them in combination into one lengthy piece, making a whole message — on this case, instructions to a small LCD display screen that can show the word “Hi, Tape I2C”.

We’re no longer certain precisely certain what’s within that oblong widget epoxied to the ground of that perf board wherein the tape passes. However obviously, it should comprise a couple of LEDs to light up the tape and a couple of sensors to discover the mirrored image off the tape (having a look on the wiring, it kind of feels not likely that the rest is fixed beneath the tape). In keeping with one machine-translated Twitter message, detection is finished the usage of a Schmitt cause constructed from an LM393 comparator with hysteresis (see this TI app word(*16*) for a assessment of this sort of circuit). Right here’s a scope seize of the ensuing alerts. [Shapoco] notes that the circuit can perform a lot quicker — the tape is being pulled slowly within the video to provide help to see.

(*10*)紙テープI2C、動いた🌵

paper tape I2C #shapolab(*16*) %.twitter.com/9WYa2mxv0T(*16*)

— シャポコ🌵 (@shapoco) March 21, 2021(*16*)