USB output?

[nicpottier]

This looks super cool! Realize you have what you need here and likely aren't interested in adding this yourself but what do you think would be required to add USB support to this with a simple serial interface to tare and get weight? Power could also come from there.

Having an inexpensive standalone option that did both BLE and USB would be a super unique (and useful) offering.

[beeb]

Hey there,

Thanks for the suggestion. I think it would probably be quite easy to set up a serial channel over USB and listen to tare commands as well as send the weight. But what would be on the other end is the question.

Did you have a specific use-case in mind? The web-app could potentially use the Web Serial API to communicate.

However, the intended use was with a tablet or smartphone, which usually have BLE capabilities, and I'm having trouble to imagine when and where USB would be superior.

USB can already be used as the power source if a battery is not desired.

[nicpottier]

This is admittedly far down the path of coffee insanity, but I'm building a Raspberry Pi server for the Decent DE1. Ideally I'd love to keep everything hardwired instead of having BLE involved. There are current scales used and integrated such as the Skale2 which sit under the drip tray and stop shots at a particular weight etc. But those are all BLE and as I said since we'd already prefer a USB cable powered scale, having that cable run to a Pi and also having reliable serial communication would be very elegant.

In any case, no expectations of you adding this at all, was just curious from a technology perspective! If we do head down that path you may see a PR come your way.

[beeb]

Thanks for the clarification. Indeed this seems like a pretty specific need. I am wondering if any standard already exists for serial communication with scales. If you already have any resources or ideas, please don't hesitate to share. I think the code base is simple enough and PR's are welcome!

Best,
Val

[adrianmihalko]

This project is awesome. I am not asking for USB support, but for a mobile (iOS, Android) app. Filtru app compatibility for filter coffee would be great too, but I am asking too much. 😀👍

[beeb]

Hello @adrianmihalko
I think a native app would probably not be needed since web browsers nowadays can have a decent amount of interaction with the host OS. I could imagine utilizing local storage to store recipes or recordings, or even a cloud service like google docs or dropbox. If there is additional features that you would want to see added, please open a separate issue.

I'll look into the Filtru app thing but it will probably be on their side that they need to support this scale. Please bear in mind that the load cell I used is rated for 500g, which in most cases will not be enough for filter coffee equipment. Load cells that support higher loads are often of different shape and mounting pattern so a different design would be needed. That's anyway something I want to develop at some point, then maybe I can get in touch with Filtru.

Best,
Val

[adrianmihalko]

Thanks for the response. I hope you will continue with this project and find some other load cell which will be capable for filter coffees as well and thus making this scale a really universal best DIY coffee scale on the planet. I think for filter coffee we don't need a very complex app: live weight tracking, timer, flow rate in g/s.

[philgood]

This is admittedly far down the path of coffee insanity, but I'm building a Raspberry Pi server for the Decent DE1. Ideally I'd love to keep everything hardwired instead of having BLE involved. There are current scales used and integrated such as the Skale2 which sit under the drip tray and stop shots at a particular weight etc. But those are all BLE and as I said since we'd already prefer a USB cable powered scale, having that cable run to a Pi and also having reliable serial communication would be very elegant.

In any case, no expectations of you adding this at all, was just curious from a technology perspective! If we do head down that path you may see a PR come your way.

@nicpottier I'm looking to go down the same path as you, RPi server for the Decent DE1. I wonder if the Bluetooth would connect to the RPi/DE1 app. Similarly to the Acaia Lunar scales. I'd really like to build these scales and use it with the DE1. Have you come across this?

[beeb]

If someone can find information about the protocols/data formats that are supported by the Decent app, I could see about changing the internal data format for the scale firmware. Let me know your findings!

[nicpottier]

@philgood I mostly gave up on this, there didn't seem to be much interest among the community sadly. I haven't kept up lately but I think there was still some talk to make direct wired connections to the serial bus easier (for DE->Pi communication) but ya, the scale would still be something that would need to be connected to from the Pi.

The decent app communicates through Bluetooth and there is support for various protocols. @beeb perhaps the easiest would be emulating one of the currently supported scales. One choice would be the Skale2:
https://skale.cc/en/skale_open_sdk.html

[philgood]

I have been investigating the bluetooth protocol for the Decent DE1 and I think you have nailed it on the head @nicpottier. I think the best way moving forward is to leverage off another smart scale that has been supported, like you said the Skale2.

This is the config for the DE1 app communicating to the Skale2, as well as other smart scales.
https://github.com/decentespresso/de1app/blob/main/de1plus/bluetooth.tcl

@beeb Hopefully this is something you'd be happy to incorporate as I'd really like to use build and use your project on the daily!