While I very much love my Robot, I came to understand that its capabilities far exceed mine. That is, paired with my (I'd say very proper) grinder, it is capable of producing superb shots and consistently so, if I were up to the task. While I do my bit of RDT, a furious WDT, an almost level tamp, and try to get my pressure profile juuust right, I still miss the mark when it comes to ending the shot.
With bottomless, I can kind of tell when I need to stop based on color and volume, and my consistency improved over time, but it's still me who is adding the inconsistent parts.
That's why I'm using a scale, and with that my Robot and I got very consistent, but there's a problem which others have also experienced: My scale doesn't fit under the Robot straight, and when I tilt it a bit so that it fits, I can't fit two cups. With certain cups and the spouts, the added height of the scale would be a problem. Another problem is that with the spouts, I can't see the color as well anymore, and mentally adding the volume from two differently sized cups is not something my human brain can do. I could do a bottomless shot every time and split it afterwards, but where's the fun in that?
So I built an extension for the Robot which replaces the base plate, and is a scale.
It's made from cast acrylic sheets and the so called M5Stack (which is an ESP32 with a nice display and a few other niceties such as a charging controller and most importantly a reasonably good looking case). It also contains a ridiculously oversized LiPo battery which supplies enough juice for the scale to run >100h, but that's what I had on hand.
I'm still having a bit of trouble with accuracy of the scale (thank god nothing mechanical, "just" some small electrical issues which can certainly be resolved) which means that accuracy is about 1g, but the mechanical part is done and pulling a shot works very well. The software is in very rough shape as I'm still experimenting, but so far I've found some well working filtering techniques and was able to integrate a shot-timer. I'm planning on adding a pre-infusion timer as well, but have not come around to it just yet.
(The 20kg load cell in the pictures is not what I'm using, which is a 1kg load cell. I've just used it as an expendable construction aid.)
Paul, if you are reading this: Thank you so much for using standard components and screws instead of glue and other sh** that's not meant to be taken apart. I hope such modifications are not against the TOS of the Robot!





