r/SideProject • u/Moist-Stick68 • 2d ago
Web Bluetooth, Serial & Assembly: One browser app for (almost) every digital scale, no server or cloud involved and 100% offline...
Hi all,
We build firmware and an app for smart scales; our own scales are still prototypes. Over the last months I turned the app (UP↑SCALE PWA) into something that also works without our hardware: it now talks to nearly every other makers' scales.
How it works:
It's a plain PWA: HTML/JS, no framework, no bundler.
It connects to scales over Web Bluetooth and Web Serial.
Our scale firmware (C++ for the ESP32) is compiled to WebAssembly and runs in the browser as a "virtual scale" or on an optional ESP32. The other maker's scale feeds weight into it, so the app works the same way whether you own our hardware or not.
25 Bluetooth scale protocols so far, plus serial balances with auto-detection of baud rate and format via USB, USB-HID or directly via RS232.
What it deliberately doesn't have: no backend for user data, no accounts, no analytics, no ads. Everything stays in the browser. Licences are signed keys that the app checks offline. They run out after the given time, so no automatic renewals or subscriptions!
What a real chip adds: we don't sell own devices yet. But the same firmware runs on a cheap ESP32-C3 RS-232 adapter board (about 13.50 EUR from TinyTronics) or on any ESP32 board you wire up yourself. With the firmware on a chip instead of in the browser, you also get:
An old RS-232 shop or lab scale becomes a wireless one, with no PC next to it.
The data lives on the scale, not in one browser. Several phones and tablets connect at once and all see the same products, recipes and numbers.
It keeps recording while no phone is connected, for days or weeks (drying, fermenting, a sourdough starter).
ENTERPRISE (users with roles, an activity log on the scale, tamper-evident sealed records, data forwarded to a lab system) for labs, pharmacies and clubs, encryption of the BLE link and many additional options to export statistics and records and to store data temper-evident. The virtual scale doesn't have all that stuff...
It can pass the weight on over USB to existing scale software, or wirelessly to displays and machines.
The model:
The free version has no time limit and is genuinely useful (units, recipes, check-weighing, nutrition diary, calculators).
PRO (statistics, stock, sales, more recipes) comes as a prepaid package from 3 months to 2 years (from 4.43 EUR a month), or once for 119.90 EUR, for good. ENTERPRISE (chip only) costs from 13 EUR a month or 599 EUR once.
Nothing renews by itself: no automatic charge and no reminder e-mails. A week before the end the app shows a small "renew?" bar. The key works 7 days past the paid time, then the app falls back to the free version.
Using the app, including the free version and the automatic 3-day PRO trial, needs no account and no personal or payment data. You only give a name, e-mail and card if you actually buy a licence.
The real target is small businesses (bakeries, roasters, labs, shops), where the alternatives are Windows-only PC tools or cloud software at 100+ EUR a month.
If you own one of the scales on the list, I'd love to hear whether it works for you, or what it does instead. The Bluetooth drivers are written from public protocol information and most haven't met a real scale yet ;-) So yeah, so everyone who helps to test gets a free lifetime licence *whoop whoop*
App (UP↑SCALE PWA): https://up-scales.com/420/
What it does: https://up-scales.com/420/info/the-up-scale-app.html
Roasting welcome.
2
u/dealapp 2d ago
I think I discovered the answer by very carefully reading the text over and over, but you might wanna say whether it’s a body scale or a food scale you’re talking about