I liked your idea.
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Maybe I found the aesthetic match to my roaster (i’d like to think), i need to replace the melamine with distressed wood
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I’ve been slowly working on my Sliding Bean Bouncer design. I will have to do something about the power cord moving back and forth so that does not get kinked in anything, but all the movements work. I have not actually checked it with beans yet. I just need to get the firmware a little more stable before testing it. I decided to try an Arduino UNO R4 Minima with this design as the previous design with just the one motor was giving a slight pause every second with the timer display on the LCD. The R4 uses pin 13 for a built in LED on the board, so I had to shift my button pins down by 1.
Here is what the electronics looks like inside. I decided to use a 6 pin JST pig tail on the top and bottom which does make it easier to connect and disconnect when I take it apart again. I made a little extension JST wire to test all the buttons before putting it together.
Here is what the complete design currently looks like all together.
I also received a M6x200mm SS threaded rod and related hardware to swap the M5 rod on my Planetary Bean Bouncer. Hopefully that will be stiff enough to not bend with the 7 oz wobble disc. I will probably swap that all out in the next week and clean the wobble disc while I have it apart.
Here is the 1st test of the Sliding Bean Bouncer with 4 oz of Green Coffee beans. I need to fix the firmware a little more before trying to actually roast.
I’ve been thinking I need to get more heat out of my setup to facilitate faster roasts, or more specifically, to have a bit more buffer for windier days so my heat gun control can dial up for windy days vs. dial back for still days - to get consistent roast times. I added a plate to the bottom of where the sifter sits to avoid extra drafts. Point being, I wonder if you’re going to be able to get enough heat in that config, quite exposed to the elements. So much neater than mine!
Have you thought about using 1/2” or 1” rigid insulation around it on 3 sides and clamping the corners of the insulation together. I used 1/2” for a cheap wall barrier around a CNC machine a while back to cut down on excess chips outside the machine.
No, first step was the baffle on the bottom to prevent some updraft.
Going to be 102 degrees today, so I probably don’t need to worry about it for a while!
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Holy cats, that is hot. It was low 20s here the other morning and got to 81 today.
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I finally did the 1st roast test yesterday. The results are still promising, but beans did not get hot enough. The inside baffle seems to be most of problem keeping the beans more to the side than in the heat stream. The most promising part is that even though it did not get hot enough, the heat gradually went up even with the heat gun not always below the thermocouple. After this test, I have now lowered the cage to 20mm above the heat gun. I also changed the rotation from continuous one way to starting the baffle at the top, rotate +90, 0, -90, 0 then repeat. That should keep the beans in the heat stream and still mix them. I will probably try the next test on Wednesday.
This crazy idea is almost working. I almost got to 1st crack, and I did get chaff coming off. The main 2 problems I now seem to have are the beans not mixing well enough and the wind. Wind problem can be fixed with a wind screen or wait for a calm day (10-12mph winds from my wind gauge). Think I can put together a simple screen with some 1/2” rigid insulation I have and block 3 sides and the 4th side will be shed doors blocking that. For the 2nd roast I had a back & forth 105-degree rotation but think I need a full rotation after that to mix them better. I did a video of the 2nd roast & will probably post it when I edit it a little. I used the beans from previous roast since they only lost about 2% or less weight. Think I was at 8.5-10% weight loss with this roast. First crack should be 11-13% weight loss. I guess this is an ultra-light roast but probably will not taste good. The variation in color is from not mixing well.
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Here is the video from that roast. If you watch it, you might want to skim through it as it is 26 minutes long. I had a cup of coffee from that roast this morning and did drink the whole cup and was not earthy as I would have thought. It was better than some diner coffee, but it was the most difficult beans I have ground with my manual grinder. I am getting ready to try Klipper firmware with this machine now since I had pretty good luck with using that on my rolling plotter. Hopefully that will solve my speed limitations I have been running into using the Arduino boards. It should also give me a lot more flexibility. I plan to use the mainsail interface with it. Anyway, here is the video of the 2nd test roast.
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I am making progress with moving from Arduino to Klipper firmware on a BTT SKR Mini E3 V3. I spent a day getting the MAX31855 sensor to work. I was initially using the SPi1 pins where all the wires were together, but it would not work with them. After switching to different pins, it worked. It would have been a lot cleaner wiring if that worked. Here is that spaghetti connection. The X-endstop and buzzer will be on JST connectors with the buzzer being attached to a fan connector. Should be able to just momentarily turn the fan on/off to buzz it.
I’m about ready to try this again when the wind dies down. I do not want to add that variable again. I have Klipper working, but it does not look like I can adjust the speed of the steppers (even when defining them as manual steppers) on the fly because Klipper wants to finish a movement before you can change a speed. That may not be a problem if I get a decent speed combination. The back-and-forth rotation of the beans did not seem to mix them well, so am going back to a full rotation at higher speed. The internal agitator I have bent close to the inner side. That kept the beans from being more at the bottom, so does not seem useful for my situation. If I rotate it the correct way the beans will just slide over that agitator. My current thought is to run the rotation axis at a continuous 40rpm and the sweep speed at 20mm/sec. That moves the heat gun about 3 full cycles or 6 times under the beans a minute. I have the motors set to continuously run for 30 minutes. I will shut the heat gun off when the beans are done and just let them run until beans are cool. I will need to cover the electronics more from the flying chaff but have them mostly open for now. I also have the cage and heat gun centered on the C-Beam now.
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I roasted a bunch this weekend and it was a little warm, seemed I was getting lots of roast variability from bean to bean, some lighter some darker in the same batch. With the idea that maybe some are scorching too fast I started varying the heat gun power with the SSR. My LED lights in the garage don’t like that! (flicker). I think it helped, the next batches seemed more even.
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