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· 07/04/2020 10:27 AM
Happy 4th of July! jazzyhands

· 06/24/2020 7:58 AM
@Mark McCornack, Please post your question in the forum.

Mark McCornack
· 06/15/2020 9:28 PM
Hi! Looking for a legacy inlet temp sensor on 13 yr old Gene Cafe. It seems they've changed it and now you need new mother board and new sensor. Any ideas where I can find compatibile old one? Mark

· 06/09/2020 6:39 PM
Wich thermometers Can i buy for my roasting machine compatible with usb or macbook?

· 06/05/2020 5:38 PM
peveleth, It is better if you start a post in the forum with your question. These shouts go away in time.

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Help in data logging and (perhaps) automating the roasting in my rottiserie oven
Hi everyone, it's my first post here. I'm from Malaysia and have been playing around with coffee roasting for about 6 - 7 months now. Our currency is weak and I'm also a bit of a little Dr Frankenstein so I got myself a 38l rottiserie oven (on hindsight, it's way too big), took it apart many times and this is what I currently have.

DC driven speed adjustable worm gear motor mounted on the outside. Rated for up to 65rpm, have never used it at full speed, at most 4/5.

Omron digital temperature controller E5CC-QX2ASM-800

K-type thermocouple

I've shifted the upper heating elements to the bottom to give me more radiant heat power. The sides and top have rockwool insulation although the heating still gets very hot. Anyway, that's just an afterthought just because I can kind of thing.

I've also shifted the rottiserie mounting point so that the basket is within an inch of the heating elements. Might go back to the stock location if I get a bigger basket custom made and finned heaters for more power.

I might also add in a DC convection fan if it will help my roasts.

Ignore the second PID. I got the wrong type. Was for relay switching. The cheap cooking thermometer is used as a timer sometimes and at other times, I use it to look at the difference in temperature at the bottom near the elements and the middle of the chamber.

I've bought an Arduino Uno some months ago but I have to admit I'm crap with software and electronics stuff although I'm alright with modifying hardware.

So now the big question is ....

Is it worth the time and money to get this setup Artisan controlled?

I've done like maybe 25 - 30 roasts with this oven from stock to current. Perhaps 15 - 16 roasts in the current configuration. The roasts aren't too bad and are pretty consistent. House smells lovely after each roast so I must be getting something right since it doesn't smell like a BBQ like in the beginning.
Artisan controlled which way ?
Experimented some months with similar drum, and BT acquisition is near mission impossible, so how do you expect Artisan help you ?
Profile following? Hmmm...

As much convection as you can would be the first improvement to focus.
Having an uniform hot air mass in the whole oven can help you roast based on ET instead BT, method less used, but better in such cases.


renatoa wrote:

Artisan controlled which way ?
Experimented some months with similar drum, and BT acquisition is near mission impossible, so how do you expect Artisan help you ?
Profile following? Hmmm...

As much convection as you can would be the first improvement to focus.
Having an uniform hot air mass in the whole oven can help you roast based on ET instead BT, method less used, but better in such cases.

Yeah, that's the downside with an oven. If I could get someone to build me a solid or stronger drum with struts inside, then perhaps I can have the left side open up to a funnel where I can insert a long thin thermocouple. Was looking at infrared probes but I might as well get a proper roaster then.

As for convection, the stock fan is near useless so one idea was to make a small hole in the center of the back wall and mount a bigger DC powered fan on the outside with the propeller inside. Will this help in getting more and more even heat transfer to the drum?
There are solutions even for your oven, requires tinkering, but not as much as building a drum from the scratch.
You can suspend the non motorised side of the drum on two rolls, by moving the right side actual support bar to a lower position, and find a way to mount two rolls from hardware store, for example those used for sliding gates/doors.
If this operation succeed, you can remove the shaft on the right side, and cut an opening in the wall, big enough for a probe, small enough to not spill beans. Possible the removed shaft hole be enough for this job.
I did such transformation, but that machine no more exists, to show you a picture.

For better convection I think the air should come from below.
You can use a convection oven full metal blower used, that is cheap, under $20, check scrap metal warehouses.
Edited by renatoa on 12/18/2019 3:01 AM
I've seen a lot of convection ovens have their fans at the back wall. Will this still work? I'm asking because it's a whole lot easier to make a hole in the bare wall and mount a fan there rather than at the bottom. Some the motor itself will be outside the oven, it'll also be working in a much lower temperature.

As for the drum, thanks for the idea but I'll like the capacbility of doing up to say 500 - 600g roasts easily if I were to upgrade the heating elements and so a larger custom made drum will have to be fabricated to make better use of all that empty space. I believe you meant something like this Kaldi roaster.

How were the results when you had a probe inside the drum? Were the readings accurate?
Yes, the solution I envision is similar to kaldi, without the funnel part. What I tested used rolls supporting the drum edge itself.
The key factor common to both is the central opening for the probe.

If you want to discuss alternatives, as is debated in other recent thread here, 5-600 grams can be done much easier (and correct) with a turbo oven (TO) lid based design, than any other home built solution, imo.

Related to best fan placement, is important also where is the exhaust from your oven... kaldi is a top open machine, not the case of yours.
Try visualise the airflow inside the oven, the goal is to carry heat from the burners to the drum, and then outside. If this path miss either the burners or the drum... is a blind bullet.
Talking about turbo ovens, I do have one of those and with a stronger blower, they could be reworked into an immersion type of fluid bed roaster, can't they?

The immediate problem would be where is all that chaff going to go.
Ok, let's say we focus on one thing at a time and go back to improving what is sensibly possible with the oven. I thought that the convection fan was just to ensure no dead spots and even out the chamber temperature? Because I was thinking along that route when I thought of placing the fan at the back wall and just having it circulate chamber air.
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