It’s a good find!
Thanks for the feedback all. We will either add more options or look into ways to make this more versatile.
@blacklabs I wanted to open this thread, but found out someone already did. It would be nice, since I also use Roast Vision. The problem with low numbers for the Agtron conversion should be fixed too, by using the gourmet scale. The site is still there, but it says out of stock. I bought mine a couple of years ago, but didn’t know they went out of business. Well, it’s a niche market and they were only selling to US customers, although, paying a bit more for shipment + taxes and customs, you could get it to Europe, which is what I have done. All included, I paid about $400. Still half of what the Tonino costs.
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This is great. Thanks for the tip. If I ever have problems with my Roast Vision, I’ll assemble a new one. The prices are pretty much the same in Europe.
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I believe that Agtron Gourmet is from 0 to 133 or so, but I suspect 120 would be fine. The highest I’ve roasted is 112. I’ve seen others reporting 115. I think 110 was the highest I’ve measured from Wendelboe’s coffee.
I built this roast-meter and I am in testing mode now.
So far, I like it.
Two things in particular that I like are the internal battery and the algorithm they are using that outputs directly to Agtron values.
This project uses the same electronic hardware that the Espresso Vision used.
I have about $140.00 in it. That includes getting the case printed, all of the electronics and odds and ends hardware. (screws, glass microscope slide for the window)
I ran a comparison for a roasted coffee that I had on hand and it came out within a point or so of what the Espresso Vision would convert to Agtron.
Thanks for sharing the link @yakster
That’s cool!!
Any plans to make and sell these to interested parties by any chance?
Not really.
It was pretty simple.
I used Print a Thing: https://printathing.com/
You upload the STL model files and specify what material (I chose ABS) and they come back with a quote. If you say yes and give them money they outsource (like Uber) to a private party and they print it and ship it. They started printing within 2 hours of receiving the order and they shipped the case and lid 2 days later. $38.01
The print quality was okay, but it is not very polished.
If I were to do it again, I would get this made out of PLA.
The electronics cost $85.00 from Sparkfun
The screws were a little expensive, because you can’t just buy 2 or 4. You need to buy a hundred.
The same for the glass microscope slides.
I also ended up with 60 switches for $6.99 and only needed 1.
If you are going to do the battery option, you need some basic soldering skills to solder 2 wires to the main circuit board and the switch. Small wires (26 gauge) you need a smaller soldering iron or a fine tip.
Loading the code on the SmartFun main Arduino circuit board took a little while to figure out. It would be nice if there was a good step by step tutorial for the Arduino IDE interface software. But like most software of this type: “once you’ve done it once…”
Here is a screen capture of one set of the screws that I ended up ordering from Amazon
And the second set. You will need both
Bless you Bill, I just found the link to the project further up so will study this in more detail. Great post.
THANKS @yakster for sharing
Have you done something in terms of calibration, or did it go “within a point or so” just out of the box with their calibration? Do you know anyone in possession of a pricier meter to compare the two?
@ mcaillio
Thanks for implementing everything. I went back and edited all my measured roasts.
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“Out of the box” it was within a point or two of the Espresso Vision.
I was using Espesso Visions Agtron Gourmet Grind Size Validation Scale:
Their measurements are based upon “the use of a US Standard size 20 mesh sieve such that 70-75% of the particles would pass through (according to SCA cupping protocols).”
I bought a #20 sieve and ran some tests: This worked out to a number 12 setting on my Barratza Encore (YMMV)
I don’t know of anyone with a True Agtron Gourmet machine that could measure and share some whole beans at different roast levels and their Agtron ground values. But, I am looking.
I feel comfortable using this as is. (my OCD wants to go further)
I am not selling roasted coffee, so once I get used to the readings that I am getting I can use them to compare the results of my roasts.
Eventually, I will have a spreadsheet with all of my values and be able to correlate to different roast levels: City, City+, charcoal, etc.
One of the big things that I am workling on is to get very consistent results during the measurement phase. In particular: Grind size and tapping the meter on the table top with the same amount of force so that I always gett the same reading.
Yeah, I was using that, but now that I can just put in my results from Roast Vision, I don’t feel the need to add the Agtron number. The colour is something you should be consistent with in your style of roasting, and as SCA says, even if you’re 6-7 points off, it’s still good. I asked about that because I thought I didn’t do good on the exam coming within a point on Agtron Gourmet scale with my roast. Anyway, with Roast Vision, I’m getting very consistent results between measurements. I think the most important thing there, apart from grind size, is to use excessive amounts of coffee, which are still small compared to other meters. I’ve seen it all over the place even when the tiniest speckle of light passes through. Like two spoons (the one included with Roast Vision) instead of one. By the way, the best thing that comes to mind is that maybe you have a kind-hearted local roaster somewhere around that uses Ligttells, or Agtron, or some of those fancy meters and ask for a favour.
I found that RoastVision has a quirky behavior that you may want to experiment with.
The RoastVision functions by reading the intensity of the light reflected by the grinds from the calibrated light source built into the instrument. When you drop the ground coffee onto the viewing window, RoastVision calibration relies on no light bleeding thru the grinds. With that in mind…
It may be worth it to experiment with placing a cover over the grinds after you note the reading to see if there is any shift caused by incidental light bleeding thru the grinds. If there is a change, that effect from unwanted back-lighting might be managed either by using a finer grind or maybe a little larger sample or maybe just continue with the additional cover.
Bruce
ps- The shift is very small and probably is most noticeable with a very dark roast.
I agree Bruce.
I was thinking about using my black Amercain Express card as a cover…(I painted it, lol)
I think that I am getting a little confused here.
When I talk about the Espresso Vision unit, I am talkiing about the original Espresso Vision meter. However, on their website they are calling their meter: Roast Vision
When I talk about Roast Vision, I am talking about the meter that is availble through Github.
I will start referring to the one on Github as Roast Meter.
Sorry for the confusion.
He had only one meter he was selling and I recall it started out as Espresso Vision… the name of the business. The name of the colorimeter was Roast Vision.
Since then he’s apparently completed his PhD and doesn’t have time for his income generator. Dunno if the design was his or if he was reselling something else. Whichever, Roast Vision is a solid product. And apparently it lives on thru the source you found.
Me
Edit- I drilled down a little further on his site and see that I may not be grinding fine enough… he refers to a ‘very fine espresso grind’. I’ve been using something coarser than that. I use a hand-crank grinder. Getting to an espresso grind would take much more effort than I’m willing to provide. Blocking the back-light is a lot easier for me. Of course YMMV…
On one of his News/Blogs, he points out that he changed the grind size to better and more accurately accomdate the Agtron conversion:
I believe that this was the final recommendation for Grind size. As I said above, I bought a size 20 mesh sieve and dialed in my Baratza Encore (setting 12) to match the 20 mesh sieve. I doubt if every Encore will match that setting for that grind size. (YMMV)
BTW: The electronics for the Roast Meter is EXACTLY the same as the Espresso Vision product, The same microprocessor, the same micro OLED board that measures the reflectivity of the ground coffee. Espresso Vision even lists the components on their website.
Therefore, I used the same grind size on the New Roast Meter.
The finer the better. I almost grind to Turkish. I have all Eureka stepless grinders, so I wouldn’t know a number for it. As soon as I grind coarser the results shift and aren’t consistent between measurements. I don’t think covering the coffee with anything would give you better results. There’s interference all the same, be it from bright or dark colours if they pass through coffee. If you grind finer than 20 mesh sieve, there wouldn’t be significant differences, except for clumping which could create spaces for things to pass through.
I found that Onyx Coffee Lab sells roasted coffee and share the Agtron level that they roast to for each coffee.
I bought five 4oz samples with agtron Values from AG53.4 to AG75.
I then worked on getting consistent results/readings with the Roast Meter.
I used the finest grind setting that I could with my Baratza Sette270. It looks like I am at 250 to 300 microns under a microscope. Turkish grind.
Then I started measuring the Onyx coffees and recording the values that I was getting different readings from the Roast Meter. It was off about 20 points. I went into the program for the Roast Meter and adjusted the led brightness value to 105. (it was 135. It took several attempts to get it where I wanted it)
Now all of the Onyx roasts are close to the Roast Meter except one. I am assuming that roast is off.
Overall I am pleased. For the price, it is a good tool and will suit my needs of having a less subjective analysis for my records.
I found that when I used a coarser grind, there were flakes of chaff that had to be affecting the measurement. by grinding extra fine, the chaff gets ground up.