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Amplifying Sound of FC
oldgrumpus
Not sure if this is the right forum for this, but since detecting FC is related to roast profiles, I thought it a good bet.

I've looked all over the forum for ideas to help more easily hearing first crack. My roaster, although relatively quiet for a drum roaster is still not easy to accurately hear first crack. I've seen a lot of ideas about using electronically generated visual graphs, but for me, I'm looking for something that doesn't require my eyes to be diverted from other important things, especially so close to the end of the roast and watching percentages and temperature... yada, yada...

It seems like it might be possible to use something like a megaphone (visualize the old person with the horn in their ear and yelling, "Eh?....Eh??") Might it be possible to install a cone through a hole in the front plate of the roaster with the big end outside? If so, maybe it needs something to prevent air from being pulled in, like a fabric or similar.

Or maybe a stethoscope? A high temperature transducer or microphone and a small amplifier-speaker?

Please tell me your ideas! Nothing complicated please...
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
CK
On both of my machine builds I've used aluminum foil stretched smooth over a custom opening (like a pipe for example) and held in place with a stretchy high-temperature silicone gasket. First crack sounds can pass through the foil nicely.

In your case, maybe a custom lid for your greens hopper with aluminum foil sandwiched between 2 layers of wood or other material. Its shape is kind of the megaphone idea you mention. You'd need to leave your metal charge gate open for the sounds to reach the foil for sound transmission, but it could be worth a try. Not sure if that would affect chaff flow too much or not...

Before fabricating something you could just lay some foil over the hopper and wrap the edges temporarily to test if it works in your case.
 
oldgrumpus
You’ve given me some good direction! Probably try foil replacing glass in the dump door just to test. I like the foil idea. Will see if getting it closer to the beans is a good idea or not. Thanks!
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
CK

Quote

oldgrumpus wrote:Probably try foil replacing glass in the dump door just to test. I like the foil idea. Will see if getting it closer to the beans is a good idea


Replacing the glass would work perfectly. Good idea. I suggest using some type of wire mesh on the bean side with foil next to it on the outside. That way the foil won't tear.
 
Microfiche
I would love any info or links on this as well.
I only have hearing on one side, and it is quite poor, aided with a hearing aid.
In my 18 roasts so far with my SR800, I have been able to hear first crack maybe 30% of the time?
Never heard a second crack so far, though I am pretty sure I have hit it a few times, based on roast colour.
I have seen a few projects like this one https://www.home-...43169.html, but none of them seem current or maintained.
Retired, newbie roaster, long time coffee lover, with Phidget connected thermocouples in SR800
 
oldgrumpus
I like the idea just posted above having Artisan “learn”, yet at the same time, I feel like I personally would like to rely less on electronic solutions. I’m almost 70 y/o, and find some romantic notions of the craft very satisfying. Sorry about the philosophical treatise 🙄. I’ll be roasting soon with the foil experiment and if successful, I’ll develop a more unique integration onto the roaster. 🤔
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
renatoa
Similar subject thread below, with some solutions.
https://homeroast...ad_id=6431
 
oldgrumpus
I posted a short video with my solution. Please forgive the corny thumbnail...


Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
CK
Nicely done! Innovative, low-tech, yet highly effective solution. Might have to copy your work for better 1C detection on my roaster. At the same time I'm hoping to integrate a water quench feature through the horn... to be continued.

Thanks for posting.ThumbsUp
 
renatoa
If still of interest... https://homeroast...post_77443
 
oldgrumpus

Quote



The author of this article makes a good point. It may reveal some improvement if implemented. I’m not sure, but it would be interesting to try. Thanks for posting it! I would like to see how the CO2 sensor is added and watch how it is used to obtain the proper clues from the on-screen data. (I’m mostly a visual learner).

An after thought: since a CO2 probe is sniffing gas, I would imagine that in a coffee roasting application, it may be subject to a deterioration in the accuracy of its readings as it accumulates the same matter that deposits in the exhaust system.
Edited by oldgrumpus on 09/29/2023 11:11 AM
 
Yasu
I use the CO concentration as a reference for FC and roasting degree.
The sensor itself is very cheap (4$) and I can replace it if it shifts due to dirt.
However, I have been comparing the two sensors and have not seen that much difference. (The dirty one and the new one)

I'm not sure if the CO generation is directly related to FC, but I think I can reliably identify FC with a sharp start-up!

https://ja.aliexp...02561632_1
 
oldgrumpus
Thanks for the link to the sensor! I will check it out and hopefully be able to integrate it's output to Artisan (that's where my skills are quite weak, at best).

But I see that it doesn't list carbon dioxide, but it DOES list carbon monoxide. So maybe this is useful parameter for our purposes?
Edited by oldgrumpus on 10/02/2023 11:19 PM
 
Yasu
If anything, carbon monoxide concentrations increase with the timing of the FC.
The output of this sensor can be converted to rs485 MODBUS RTU and imported to artisan easily and cheaply via USB.

https://ja.aliexp...pt=glo2jpn

https://ja.aliexp...06550187_1
Edited by Yasu on 10/04/2023 2:45 AM
 
oldgrumpus

Quote

Yasu wrote:
The output of this sensor can be converted to rs485 MODBUS RTU and imported to artisan easily and cheaply via USB.


Thanks Yasu!
 
Yasu
Not that it matters here.
I believe that with such a converter, temperatures can be imported into artisan with a display for about $15 per circuit.

https://ja.aliexp...06485795_1
Edited by Yasu on 10/04/2023 3:14 AM
 
Yasu
Let's go back to the first crack.
Why do you want to know when the first crack is?
Naturally, it is to determine the time of Development time, and also because you need to adjust the heat there to get the best baking results.

Rest assured, even if you don't hear the first crack, you can know that the first crack in the beans is starting by knowing that the carbon monoxide concentration is rising.
The sound of the first physical crack is usually heard about 60 seconds after the first crack inside (when the carbon monoxide concentration rises).
But I use the sound as a reference, adjusting the heat at the time the carbon monoxide concentration rises, and the time from that point to the end of the roasting process.

The carbon monoxide concentration rises steadily as the roasting progresses, but it stops rising at a certain point.

At that point, the shallow roasting is complete, and the aroma is wonderfully fruity.

From that point on, the carbon monoxide concentration rises gradually as the roast gets deeper and deeper.

There is no way to avoid using this value as a barometer of roasting!


What is the first crack?

Yes it is when carbon monoxide begins to form in the beans.

I try to understand and act accordingly.
Edited by Yasu on 10/05/2023 12:41 PM
 
Yasu
BT and carbon monoxide concentration (ppm).
The zero point of carbon monoxide is off, but don't worry about it.
The first crack starts about 60 seconds after CO starts up.
When the CO gradient is sleeping again, the FC is complete, and then you can drop it at any time you like.
Yasu attached the following image:
co.jpg
 
renatoa
Such components are rated at 70C degrees if commercial grade, or 85-125, if industrial or military.
The exhaust air of a coffee roaster is much hotter, so how do you mount such, to sniff safely the monoxide ?
 
Yasu
Exhaust air is sucked from the exhaust duct with a φ4 silicon tube using a feed pump, but if a φ4 annealed copper tube of about 3 m in length is coiled along the way and passed through it, the temperature drops to almost room temperature, so sampling is easy.

Even though it is 3m, it does not take up that much space since it is3 rolls of 30 CM in diameter.

https://ja.aliexp...6498841%21

https://ja.aliexp...20192523_3
Edited by Yasu on 10/09/2023 8:09 AM
 
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