It might take you some time to understand what’s happening in the video that Hackaday alum [Moritz Sivers] shared with us. This is [Moritz]’s contribution for this year’s Pi Day – a machine that shows digits of Pi in a (technically, not quite) infinite loop, and shows us a neat trick we wouldn’t have thought of.
The two main elements of this machine are a looped piece of thermochromic foil and a thermal printer. As digits are marked on the foil by the printer’s heating element, they’re visible for a few seconds until the foil disappears from the view, only to be eventually looped back and thermally embossed anew. The “Pi digits calculation” part is offloaded to Google’s pi.delivery service, a π-as-a-Service endpoint that will stream up to 50 trillion first digits of Pi in case you ever need them – an ESP8266 dutifully fetches the digits and sends them off to the thermal printer.
This machine could print the digits until something breaks or the trillions of digits available run out, and is an appropriate tribute to the infinite nature of Pi, a number we all have no choice but to fundamentally respect. A few days ago, we’ve shown a similar Pi Day tribute, albeit a more self-sufficient one – an Arduino calculating and printing digits of Pi on a character display! We could’ve been celebrating this day for millennia, if Archimedes could just count a little better.
Could not find a source for thermochromic film. I wonder where [Moritz Sivers] / {Moritz} found it.
This might be helpful. https://www.tiptemp.com/Products/Thermochromic-Sheets-and-Films/
No clue where the creator got it from, but a quick google shows a lot of vendors for ‘thermochromic film’.
@vib said: “Could not find a source for thermochromic film. I wonder where [Moritz Sivers] / {Moritz} found it.”
* 3 Packs Liquid Crystal Sheet 6 x 6 Inch Heat Sensitive Sheet Temperature Sensitive Liquid Crystal Sheet 6 Color Changing Heat Sensitive Board, 24 to 34 Celsius Degree Transition for Science Experiment $19.99
https://www.amazon.com/Sensitive-Temperature-Changing-Transition-Experiment/dp/B09MH54SMW
* Thermochromic Sheets & Films
Thermochromic material can be used to monitor hot spots on circuit boards or advertising. They are available in various size formats. 6″ x 6″, 12 x 12″ or 12″ x 18″ and can be cut to fit your application. Additionally we can supply 54″ Wide x “tell us how long”. Sheets come With or Without Adhesive. Lexan material is dull and will not show finger prints. Polyvinyl is shinny or VInyl Flex ( TLCSEN455 & TLCSEN456 ) is available in B lack or Blue and has one specific temperature 25°C ~ 30°C
https://www.tiptemp.com/Products/Thermochromic-Sheets-and-Films/
“thermochromic sheet” or “liquid crystal sheet” also yield interesting results.
I got some from https://colourchanging.co.uk/collections/thermochromic-sheets a while back, but they are also available from more bespoke sources: https://www.edmundoptics.eu/p/40-45deg-c-temp-range-liquid-crystal-sheet/24204/
Thanks for the link!
I wonder if some kind of cooling system on the bottom side would help with readability after it’s been running for a little bit.
This – a small fan/heatsink/peltier cooler would do it.
Fascinating. Had no idea that foil was even a thing, this is a great application of it.