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  • Arduino stop-by-weight espresso scale - project

In the desire to automate and make my espresso flow more consistent I thought a custom scale would bring some benefits, that is, to stop the shot at a target yield. I’ll get a bit into technical details so feel free to skip forward to pics and video if it gets too much :)

I am using Arduino nano which proved to be quite convenient to program and find documentation.

The weight is measured with a load cell (HX711) which seems to be quite popular and easy to connect and work with from Arduino.

The connection with the espresso machine is done wireless, using 433MHz RF transmitter in the scale and a receiver in the espresso machine that’s connected to the shot switch with a relay. The RF tech is the one used in garage doors and stuff like that :)

The scale is powered by a 18650 cell which is rechargeable via usb.

The case is also custom designed and 3d printed, it has some questionable design choices you may say, but the reason I put the buttons on the side is to have a clean face and to avoid liquid ingress.

In terms of software, nothing ground shaking just few mentions: I am calculating and display the flow (easy thing to add since you can do anything in code), compensate for shot overflow (stop the shot a bit earlier than the target weight), and something I want to later, show a graph with the flow(not sure how it will look on than tiny display).

The espresso machine is Rancilio Silvia Pro.


    This is really good! I was thinking a while ago about something similar, but wanted the scale to be part of the drip tray of the machine itself, so, in a way, something that I don’t have to worry about and think it’s there: I put the cup on top, it auto-tares, I turn the machine on and then it stops as per your project.

    This is really good work, well done!

      This is really awesome, nice work.

      Do you think it would be possible to make a similar setup for a grinder? I’ve given up entirely on timed grinding as the variables make it a pretty futile endeavour.

      I’d love to be able to add a grind by weight module to the Super Jolly. I can technically fit my scales on the cup rest but the accuracy isn’t great and obviously it doesn’t shut the grinder off.

        Ernie1 I think you can, the grinder might have slightly more vibrations and it might cause noise in weight reading, but you can def smooth that up and compensate in software, if needed.

        It is done in pro grinders so it can work. Baristas often critique this feature because is slow in taring due to a lot of vibrations that are on the counter top but that’t probably not a problem at home.

          Don’t think any grinder has more vibration than Silvia 😆

          Great work!

            Inspector hahaha amen to that! It even has personality, it rattles differently sometimes, depending how the hoses move in it!

              Very cool

              Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

              a year later

              Hi. nice project. Can you share all parts and wiring diagram? Thanks!

                Winner Hi. nice project. Can you share all parts and wiring diagram? Thanks!

                Welcome to the forum, the ingenuity of our community never ceases to amaze me.

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                  a year later

                  Hi, I’m pretty late at this time but, I wanna do this project also, but I am wondering if you used a 5Kg loadcel or a 1Kg loadcell. This would help me because many of hx711 sells 5Kg loadcells but I’m wondering if it would work better with a 1Kg loadcell.

                  Thanks a lot,

                  Sam