next roaster sensor: a Microphone

[Hildy]

Cracking the code for a perfect coffee › News in Science (ABC Science)

[Hildy]

I mean a microphone.

[chokkidog]

:-D HaHa. Good typo!!

Saw this article in 'Roast' a couple of weeks ago.

Interesting, especially for people who roast and whose hearing is deteriorating, it could be hooked up to a video display monitor

so that the progress of first crack can be monitored by the frequency and amplitude of the visual sound spikes. It would also help

pinpoint those very first snaps of second crack which can be hard to hear in a big roaster, then you could easily adjust your profile to avoid 2nd

if that particular bean profile was hovering around that point.

I had a chat about it with Andy last year, even googled high temp mics to see what was available.

[Barry_Duncan]

automated roast monitoring research

Cracking the code for a perfect coffee

Can the cracking lead to an automated roast monitoring technique?

Cracking the code for a perfect coffee › News in Science (ABC Science)

Barry

[MrJack]

Hardly a novel idea, is it.

[chokkidog]

Maybe the mods could merge the two threads started on the same topic on the same day? ;-)

If only we could hear each other! ;-)

[chokkidog]

A novel idea? Haven't yet seen a roaster with a high temp mic in it, hooked up to a display or a PLC.

[Hildy]

you don't really need a high temp mic if you can fliter out some of the extraneous noise. I might grab a mic and record my next roast.

what would be good is to have a temp sensor and mic, so you can correlate sound with temperature.

[sprezzatura]

I used to work with acoustic altimeters and acoustic hydrophones back when I was a commercial diver. The transducers are rugged - they might be modified to place into a sealed unit sort of like a HX onto the outside of a roasting drum (as near the rotating drum as possible). The membrane might be swapped for something more heat resistant. They're relatively inexpensive and, well, you wouldn't need the helium voice unscrambler unit anyway. It's doable.

[chokkidog]

I was thinking of placing the mic inside the drum, mounted on the faceplate, like a thermocouple probe, probably above the bean mass and under the exhaust outlet.

Filtering base line noise would be easy enough, given suitable software; there are mics used in high temp food manufacturing.

In reality tho' experience, sight, smell and Andy's software will do, just fine.

The mind wanders sometimes............... ;-)

[chokkidog]

Something like this:

Probe Microphones

[MrJack]

A novel idea? Haven't yet seen a roaster with a high temp mic in it, hooked up to a display or a PLC.

As my PID controller is Arduino based, I have contemplated attemping to track 1st and second crack using one of the avaliable mic shields. No high temp required. Only a step further to automate a profile based on that data.

If I've thought about it, chances are someone else has attempted it (like all my good ideas )

[chokkidog]

No worries, it's just that with a commercial cast iron drum that is insulated between drum and shroud an external mic might not work as well.

[MrJack]

True. But sound transmits well through solids, so it might be possible to mount the mic in a location remote from the high temperature.

[chokkidog]

Like a dog with a bone. Get yourself next to a roaster as described, with all the noise of drum and fan motors, maybe a second or third roaster
also in roast mode, an extraction fan, air conditioner, destoner, vacuum bean loaders, forklift.

Some beans are whisper quiet even at first crack, the first scouts of second barely audible even through the sampler tube.

I'd put mine inside.