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Show HN: PaperMono, e-ink fridge magnet shopping list with mobile web pagegithub.com

E-paper shopping list for the M5Stack PaperMono, with a FastAPI server and phone web UI - seamusc/papermono-shopping-list

149 points•seamus_c•3 days ago•62 comments•
#shopping#list#shopping list#papermono#fridge#web#x27#ink
Fridge magnet shopping list on an M5Stack PaperMono (ESP32-S3, e-ink touchscreen), synced with a phone web app over Wi-Fi. Works offline, ~2,400 lines of C++.

This is a great wee device! BLE, Wi-Fi and LoRa on one board makes it flexible for way more than a shopping list, this is just what I built first. This firmware only uses Wi-Fi.

Fully vibe-coded with Claude Code, I didn't hand-write this. I wanted to see how Claude would get on with building something useful for a new hardware device.

As it's stuck to the fridge it's easy for the family to use, and it's already being used day to day which I'll admit is a first for a home built project like this

62 comments

shitsonothersid2 days ago
Neat! I have one better though:

https://en.wikipedia.org/wiki/Post-it_note

* Works during power outage

* No battery!

* Very few remote attacks possible

* Very little attack surface

* Accepts multiple input technologies (ink, crayon, and so on)

schainks2 days ago
A gentle breeze from a running child unsticks any sticky note we have anywhere, how do you deal with that?
seamus_c2 days ago
Fair ofc :) This is more intended as a tech demonstrator and a bit of fun, although we have been using it for the weekly shop..
HelloUsername2 days ago
> Post-it note

* Produces paper waste

* Easy to lose

* Clutter

* Limited space

* Can run out of stock

* Not searchable/reusable

mft_2 days ago
* not vibe-codeable

* unlikely to hit the front of HN

shitsonothersid2 days ago
paper waste < e-waste

loss is almost costless

ok, I give you that the lack of ctrl-f is a bad thing.

jimmygrapes2 days ago
post-it notes are edible with no discernable side effects (recommend no more than 5 per 24h period, preferably 0)
m1012 days ago
I think on the app you should have an auto sort for your local supermarket. I have a list of aisles that I go through on my route around and I ask an ai to sort my shopping list by that route through the supermarket.
zikduruqe2 days ago
You'd love the Grocery App for iOS and Apple Watch. It learns based on which items you check off on your grocery list and puts them in order.

I'm like a caveman hunting my prey using it. I'm in an out with no meandering around.

https://apps.apple.com/us/app/grocery-smart-shopping-list/id...

seamus_c2 days ago
You can sort the aisles manually in the app, and there's a (hacky) route to use AI to categorise new items into an aisle. It shouldn't be too hard to use AI to sort the aisles I'd guess
ulbu2 days ago
- map aisle sequence of your store to numbers

- prepend each entry with aisle number

- sort by number

- remove aisle number

or, of course, you can outsource your brain, it might turn out to be less resource-expensive

dgently72 days ago
ive heard but not confirmed that some store chains have apis to tell you what asile to find something on, but i assume that would probably require upc info which would be an annoying extra level of specificity to need to track and manage. you just wanna write "corn chips" not... "mission brand corn chips in the 64oz bag"
schnevets2 days ago
Pretty cool! I remembered having a brainstorming session with co-workers about all the cool use-cases for e-ink displays over a decade ago. A product precisely like this was definitely mentioned, as was conference room displays, data center cage information, Kanban-style sticky notes in manufacturing, dynamic game pieces, among others. You'd think simple displays like the PaperMono would be as cheap as bluetooth speakers by now, but I know there are some major patent restrictions.

I can tell you this conversation happened over a decade ago because LCD Touchscreens were still more expensive than e-ink at the time.

lp922 days ago
Game pieces with integrated eink to track health/stats and other game relevent metrics would be an interesting application.
seamus_c2 days ago
That's a cool idea! There are small 1.54" e-ink screens, I wonder would it be possible to add an NFC chip and have them completely passive? (i.e. powered from the writer)
ex1fm3ta2 days ago
Project like this make me excited with AI. You can pretty much custom firmware, tailored for your specific needs. Thanks for this repo. Quick question to the community : why does nobody makes afordable huge e-ink displays ?
hansihe2 days ago
There is exactly one manufacturer of large EPDs, E Ink Corporation.

A few have tried to compete over the years, none have really managed to ramp up production and compete from my understanding. I believe there are some chinese firms making smaller panels now, mainly used in electronic shelf labels for stores.

From my understanding most of the patents for the foundational tech have expired at this point. I believe the panels are just generally very difficult to make, with difficulty ramping up further as panel size goes up, presumably the yield is fairly low.

j452 days ago
The last time I checked, patents.
otherme1232 days ago
Key eink patents are expired since c. 2017. But they bought potential competitors and keep innovating (and patenting), so the monopoly stays strong. If someone entered the market right now, with 2000 eink tech, and pricing at very low margin prices, they will go bankrupt: would you buy a 20" screen, no touch, ~70 ppp, refresh around 2 seconds for maybe $300? Also, patents might have expired, but key tech, such as precise micro-sphere manufacturing, is not under patent protection, but under trade secrecy: on top of old tech, it would be unreliable. Some like Zhiwei specialize in epaper for tags using old tech, but only for b2b and barely below Eink prices.

Competition explores completely different technologies: Daylight DC-1, Reinkstone, ChLCD e.g. from Iris... but either the tech isn't good enough to generalize or be cheap (the later), or the niche economics don't allow the inventors to keep investing (the two first).

seamus_c2 days ago
That was part of the motivation here: If I can think it up, can AI actually build it, even when it's outside my day-to-day experience? (and can it do it without frying the hardware somehow)
Palomides2 days ago
there's no secret, they're just expensive to manufacture
maxglute2 days ago
Neato. Every time I see a competent eink project, I remember how long it has taken to due licensing drama and how much I've aged and will age until full wall eink.

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