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Jerjer
Level 3 Moron
Registered: 12/25/17
Posts: 9
Loc: Austin
Last seen: 5 years, 9 months
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Automated pressure cooker 1
#25099506 - 03/29/18 12:44 PM (6 years, 1 month ago) |
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I was inspired by Gr0wer's automated electric PC thread, and burning up my electric burner accelerated my plans to build my own autoclave control. It's finished, and it works great. The hardware and software plans are open-source on GitHub.
The controller is a BeagleBone Black with some custom electronics to interface two thermistors for the internal and burner temperatures, a pressure sensor, and two SSRs to control the burner and a pressure relief valve. These hook up to a Presto 23qt. with burner fixed to the bottom. (I'll have to get better pictures.)

The BeagleBone runs the Machinekit machine control software with some Python-language components (the control itself, a logger, and a simulator) and a QML-language QtQuickVCP GUI that runs on Android, Linux, Mac or PC.
The control has several stages, starting out in the 'idle' stage. The run button starts the autoclave cycle, composed of five stages, and each time and temperature may be adjusted:
- 'boil': Heat autoclave to boiling
- 'flush': Open pressure relief valve, boil water 10 minutes, close valve
- 'heat': Heat autoclave to sterilization temperature
- 'sterilize': Maintain sterilization temperature for pre-set time
- 'cool': Cool autoclave to pre-set temperature (e.g. 99 deg. when pressure is zero, or 32 deg. when agar has solidified)
The control GUI shows these stages graphically, as well as presenting several controls and readouts. This screenshot is from a real run, currently 15 mins. into the sterilization stage. (The pressure sensor was adjusted incorrectly with a -0.6 PSI bias (oops); this doesn't affect normal operation.)

The logger component logs a whole bunch of process variables and generates charts, continuously updated during the cycle in a web page. The following chart is from the same real run. The grey area represents the set temperature, and the red is the internal temperature. (Orange dashed is burner temp.) The burner power is the yellow, going from 0% (at 100) to 100% (at 110). The solid orange is the pressure, and the thick blue that tracks temperature means the relief valve was open. (The other curves centering around 60 are for PID debugging.)

The whole thing cost about $200 to build (incl. PC & burner) with some thrifty eBay shopping. A handy person with basic tools and soldering skills could build one in a day.
-------------------- Just getting started! Open source autoclave control Fill in the blanks: OP: "I know __X__ is the standard practice, but I want to try __Y__ because it's new and fun!" Reply 1: "Just do __X__. Don't do __Y__." Reply 2: "Use the __X__ tek. It works for me 99% of the time!"
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Tmethyl
Smear in the shale


Registered: 07/16/12
Posts: 16,431
Loc: Florida
Last seen: 1 year, 7 months
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Re: Automated pressure cooker [Re: Jerjer] 1
#25099571 - 03/29/18 01:13 PM (6 years, 1 month ago) |
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This is incredible.
-------------------- ¯\_(ツ)_/¯
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impatientguy
Ganjalf a very mighty lab wizard



Registered: 11/26/14
Posts: 5,054
Loc: USA
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Re: Automated pressure cooker [Re: Tmethyl]
#25099609 - 03/29/18 01:36 PM (6 years, 1 month ago) |
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Pretty crazy, cool though.
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LemurLemur
Pray for Boog



Registered: 01/30/17
Posts: 6,004
Loc: Drinking on the roof
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Re: Automated pressure cooker [Re: Jerjer] 1
#25099638 - 03/29/18 01:50 PM (6 years, 1 month ago) |
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nice build, i could do this with my presto, never again will i have tonwait to cook dinner cause i already started the cycle
--------------------
 (when my data is fast play Lemur in chess at chess.com)[ [gradient:#D40B29,#18C418]Any1 expecting a trade from me i havent forgot about you pinky promise, i fr promise shits just shit rt now[/gradient]
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Apples in Mono
Not a puppet


Registered: 09/21/17
Posts: 3,240
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Re: Automated pressure cooker [Re: Jerjer] 1
#25111185 - 04/03/18 02:45 PM (6 years, 1 month ago) |
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Wow. Badass. I don't think it get's much more legit than this. Thanks for posting
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36fuckin5
Alchemycologist


Registered: 08/11/03
Posts: 12,091
Loc: Diving into Mystical Territori...
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Looks cool but why not just use your stove? They're designed to be used on the stove. You already learned from your other thread that your burner isn't really up to the job. I'd expect problems soon.
-------------------- Pat The Bunny said: A punk rock song won't ever change the world, but I can tell you about a couple that changed me. bodhisatta said: i recommend common sense and figuring it out. These are the TEKs I use. They're all as cheap and easy as possible, just like your mom.
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Apples in Mono
Not a puppet


Registered: 09/21/17
Posts: 3,240
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Re: Automated pressure cooker [Re: 36fuckin5] 1
#25113158 - 04/04/18 08:49 AM (6 years, 1 month ago) |
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I think the point is portability and full automation. A stove provides neither. And i have a feeling that this guy will be up to the task of improving upon the burner function if he runs into any hiccups
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,891
Loc: Milky way
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It's turning a pressure cooker into a rudimentary autoclave.
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Madoxx
Aspiring Mycologist


Registered: 05/19/13
Posts: 111
Last seen: 3 years, 17 days
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Re: Automated pressure cooker [Re: Jerjer]
#25135981 - 04/13/18 02:32 PM (6 years, 1 month ago) |
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Cooool thing! Crazy piece of home engineering
Will you eventually take a nap in the room where this thing is working on it's own i guess is the final question
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drake89
Mushroom Magnate



Registered: 06/26/11
Posts: 4,168
Loc: TN
Last seen: 5 years, 2 months
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Re: Automated pressure cooker [Re: Madoxx]
#25144888 - 04/17/18 06:16 AM (6 years, 1 month ago) |
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I suspect OP has an engineering degree , or OCD. Which is it?
Nice job btw.
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Tookitooki
Mycological Fabricator


Registered: 07/28/16
Posts: 1,157
Loc: Nowhere
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Re: Automated pressure cooker [Re: drake89]
#25144960 - 04/17/18 07:11 AM (6 years, 1 month ago) |
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This is awesome.
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Jerjer
Level 3 Moron
Registered: 12/25/17
Posts: 9
Loc: Austin
Last seen: 5 years, 9 months
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Re: Automated pressure cooker [Re: Tookitooki] 1
#25161822 - 04/24/18 08:30 AM (6 years, 26 days ago) |
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Someone asked privately about pressure transducers, and the information might be useful to others, so I'm answering here.
First, the pressure transducer isn't really necessary in this setup. I added it because I could. In the current code, the only function it has (aside from a readout) is a redundant sensor for safety (the autoclave will disable itself if pressure exceeds a set maximum). The pressure readout can easily be hooked up to the temperature sensor. Also, the reading of at least the sensor I used would drift: if initially set to zero, over time it would have a bias of up to -0.6PSI. I have ideas for why, but it doesn't seem worthwhile to spend effort fixing when the temperature sensor is sufficient.
If one really wants to play with a pressure transducer, the cheap one I used are on eBay and Amazon, for around $15-$25. My code and electronics are set up for the 0-30PSI, 5V models. Try to find one that shows a max operating temperature of above 121 C. Examples:
- This one on Amazon, $29, 125 C. - This one on Amazon, $18, 125 C. - This one on eBay, $18, 120 C.; this is the one I have; although <120 C., it has survived a dozen cycles now
Also, reading the reviews, these sensors are cheap and crappy, and apparently blow out all the time. Again, probably more trouble than they're worth. More money than they're worth too, even at $18.
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drake89
Mushroom Magnate



Registered: 06/26/11
Posts: 4,168
Loc: TN
Last seen: 5 years, 2 months
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Re: Automated pressure cooker [Re: Jerjer]
#25161860 - 04/24/18 09:06 AM (6 years, 26 days ago) |
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A professional grade pressure switch is about $200 , but they could last 20 or 30 years.
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donrjuan
On the Grind


Registered: 10/20/10
Posts: 534
Loc: State of Boredom
Last seen: 3 months, 10 days
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Re: Automated pressure cooker [Re: drake89]
#25187971 - 05/06/18 02:52 PM (6 years, 14 days ago) |
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Nice work
I was wondering about using a RaspberryPi when I read Gr0wer's post. I have built a few beer brew controllers as well as two still controllers using them and I believe it could be easily adapted. Plus you could work in a Pi controlled valve to vent off in the beginning to prevent cold pockets. Simple temp checks coupled with PWM to control total power to your element. Could be super nifty!
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eldearmano
Stranger



Registered: 10/07/16
Posts: 410
Loc: Colombia, South America
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Re: Automated pressure cooker [Re: donrjuan]
#25224271 - 05/23/18 09:54 PM (5 years, 11 months ago) |
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IT"S ALIVE! BUT
Wouldn't a timer on your phone work just as well? I'm trying to figure out what the benefit would be in terms of time savings - and from the standpoint of return on investment. I mean, yea, it's a testament to your ingenuity, but you must be doing a lot of volume to need something like that - your time is obviously worth a lot more than mine is lol.
-------------------- On a quest to find the undiscovered mushrooms in the Sierra Nevada Mountains of the Caribbean coast of Colombia, South America.
  
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Throwawaygrower
Secret ninja


Registered: 06/18/18
Posts: 141
Last seen: 3 years, 4 months
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Re: Automated pressure cooker [Re: eldearmano]
#25282933 - 06/21/18 09:51 AM (5 years, 10 months ago) |
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Do you have any more pictures of the hardware part? couldn't find any on the github
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tedoro
ToadStool Tender



Registered: 02/06/15
Posts: 2,218
Last seen: 3 hours, 1 minute
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Re: Automated pressure cooker [Re: Jerjer]
#26428092 - 01/11/20 01:16 PM (4 years, 4 months ago) |
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Old thread.... but.... Has anyone heard of someone using an InkBird Thermostat to control a hotplate.... you know, tee off the gauge stem and insert the inkbird temperature probe.
Seems like it could work....
-------------------- -------------------- Deep pour soft agar plates-->bags of WBS-->Low Profile Monos Clean spawn thread | Put a thermometer on your PC
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IamMatt
Stranger


Registered: 06/20/10
Posts: 1,071
Last seen: 1 year, 10 months
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Re: Automated pressure cooker [Re: tedoro]
#26432488 - 01/14/20 02:02 AM (4 years, 4 months ago) |
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thanks for the thread
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asymetricaljoe
Stranger

Registered: 08/03/08
Posts: 20
Last seen: 8 months, 29 days
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Re: Automated pressure cooker [Re: tedoro]
#27937378 - 09/06/22 02:53 PM (1 year, 8 months ago) |
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Quote:
tedoro said: Old thread.... but.... Has anyone heard of someone using an InkBird Thermostat to control a hotplate.... you know, tee off the gauge stem and insert the inkbird temperature probe.
Seems like it could work....
did you ever pursue this/get this to work?
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tedoro
ToadStool Tender



Registered: 02/06/15
Posts: 2,218
Last seen: 3 hours, 1 minute
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I realized that I really want to oversee its operation for safety.
So this is what I do.
https://www.shroomery.org/forums/showflat.php/Number/26742520
And I'm very pro pressure release safety valves in the stead of bobbles. I run 25psi, because the 20psi were way too quick to pop at 18 psi.
-------------------- -------------------- Deep pour soft agar plates-->bags of WBS-->Low Profile Monos Clean spawn thread | Put a thermometer on your PC
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