# Smart Grinder mod WiFi+App+Weight based grinding



## Greggan (Mar 29, 2019)

*How do you feel about this project?*​
Love it, will build it!00.00%Can't code, soldering no problem.1100.00%Can code it but losy solderer.00.00%Love it but want installation kit pre coded.00.00%


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## Greggan (Mar 29, 2019)

*Full project at my personal website* (I hope this is appropriate it free and open source).

Quite easy to build it helps to be familiar with a soldering iron and Arduino projects.

Full code and wiring writeup free for any Coffee Geek to use and modify for personal use.

Project will be further developed to include possibility to change the grain setting from app too.









A second project that are a bit easier to build will also be published soon (Timer controlled with presets).

Kind regards/Stefan

https://www.stockholmviews.com/wp/weight-based-coffee-grinder-with-blynk-app


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## DavecUK (Aug 6, 2013)

Interesting project, keep up the good work.


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## rob177palmer (Feb 14, 2017)

You should be working o a better grinder than a rocky, but the project looks really interesting!

Not for me but good luck with the designing.


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## ajohn (Sep 23, 2017)

Interesting. I wondered about this approach due to getting a cheap decent load cell with the right range plus platform etc. Probably best to base it around 1 or maybe 2kg scales to cope with portafilter weight.








Not much chance of me doing anything in this line. Wrote way too much of the stuff while being paid for it but suspect there is plenty of scope for something that would work even with grinders that shoot it out at very fast rates but that is likely to be a little more complicated.

John

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## Greggan (Mar 29, 2019)

Will post some results of precision when I converted my Rocky.

The tech is absolutely possible to adapt on other "dumb" grinder of anyones taste if that is desirable









It would be too hard to create a load-cell portafilter holder either.

The quality of load-cells certainly make difference in respect of data stability and calibration drift but since

you always tare it before grinding it wouldn't make too much difference.

I use a 10€ 500g scale and put a 100g container on top to grind in to, resolution-vice it is best to stay midrange of the scale (I believe).

During my "Dry tests" with calibration weights I have stayed within a tenth of a gram and that is precise enough for me.

I know that a few more variables will be put in play when it are in use in real grinding situations like , vibrations and uneven feed of ground coffee.

However the response is configurable and right now the scale are interrogated every 20ms, I have also implemented a correction calculation for over/under grinding that can be adjusted for given type of grinder and grain size.

I do have a second software version that omits the scale and use timer instead (need to be calibrated depending on grounding grade).

Will update this thread in regards of my findings and which version I like best









Build test fail tweak test fail twea......... /Stefan


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## Greggan (Mar 29, 2019)

Or a counter balance to compensate for the Portafilter/container to be able to use a more sensitive load-cell


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