# Curing Chamber - Raspberry Pi - Humidity Fluctuation?



## hjbct (Jan 5, 2016)

Hi - just finished prototyping my new curing chamber controlled by Raspberry Pi and using Google Sheets as GUI.  I plan on a full build writeup soon.

Question - the humidity fluctuates by around 15% but the average is still close to my desired setpoint.  Is this an issue?

The red line in the below is the RH (excuse the messy prototype GUI!).













Capture.PNG



__ hjbct
__ Jan 5, 2016


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## harleykids (Jan 5, 2016)

Shouldn't hurt anything with a 15% fluctuation, as long as your average remains around 80-82% RH overall. 

My min/max over time is usually 3-4% (ie. 80-84% with averag of 82%)

I am using a WH8040 for humidity control, and an STC-1000 for temp control. 
Works perfectly!

Good luck!
Jason


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## holyfeld (Jun 11, 2016)

I'm looking at adding a Raspberry Pi to my smoker for better control. Did you post you BOM and / or how you went about building your curing system?

Don


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## hjbct (Jun 11, 2016)

Hi,

I have not yet posted a BOM - i need to write it up.  Essentially, I have DH11 reading temp and humidity using the Adafruit_DHT python library.  The controls are via a set of relays, connected to GPIO on the pi.  I'm controlling heating, cooling, dehumidifying, humidifying and circulation fans.  I also have 4 load cells so I can monitor weight loss as the drying proceeds.  The GUI is managed via Google Sheets.  I use the gspread API and write the readings from the curing chamber every minute (if they have changed) to the spreadsheet.  I also read parameters from the spreadsheet.  Fairly simple to put together, but the devil is in the detail and managing hysteresis was tricky.  If you are just managing temperature, that should be easier to keep on top of.

Happy to share more details or specifics.


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## holyfeld (Jun 13, 2016)

I'm now following this thread, so I'll get notified if you update here.

Temperature control will be simpler than the curing chamber you made. 

I took a look at https://github.com/jamesgao/kiln_controller I did control systems when I graduated. Then I started doing management stuff. Now I'm looking to get back into coding, mainly for fun. I need to update some outdated skills.

Don


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