Fermentation monitoring with NodeMCU (ESP8266)

[rijnswand]

Here's my fermentation monitor using only a NodeMCU chip and some sensors.

The data is sent to ThinkSpeak for easy monitoring:
https://thingspeak.com/channels/100937

I'm also using a free Android widget that shows the data on my phone:
https://play.google.com/store/apps/details?id=ua.livi.thingspeakmonitor
The widget can also sound an alarm if the temperature gets too high or too low (which shouldn't happen, since it's inside a fridge).

Currently I have two temperature sensors connected to it, one inside the fermentation tun and one outside (inside the fridge where I have the fermentor). I also have two sound detectors so I can detect the bubbling sound from the air lock, but they are difficult to calibrate correctly. Therefore I get better data from the alcohol sensors which I have, one inside the fermentor and another attached to the air lock.
The extra red board you see in the picture is a multiplexer, so I can read multiple analog values with the nodeMCU.

About the performance:
- The alcohor sensors probably react slighty to other gases than alcohol, like CO2 or even water vapour, but they still give a clear indication when the fermentation has started.
- The fridge temperature sensor also indicates whether fermentation is ongoing, since the fermentation produces heat causing the compressor to start more often. This way I can also see when the fermentation slows down.

Parts:
- 1 pc NodeMCU
- 2 pcs "NTC Thermistor temperature sensor 10K 1% 3950"
- 2 pcs "MQ-3 Alcohol Ethanol Sensor"
- 2 pcs "KY-037 Sound Detection Module"
- 1 pc " 16 CH Analog Digital CD74HC4067 MUX Breakout Board"

The NodeMCU is powered by a standard micro-USB phone charger.

The fridge is controlled by a cheap thermostat (like this: http://www.ebay.com/itm/281764668296 ), which is not connected to the NodeMCU. It has a temperature sensor which is taped to the outside of the fermetation tun, and it keeps the temperature of the wort constant within 0.25 C, which is amazing.

I'm also planning to add a digital hydrometer to this, it will work with the same principle as the brewometer:
http://tilthydrometer.com/products/brewometer

 

[doomy86]

Nice project, love the ESP8266 platform. Sucks that the brewpi is programmed on photon.

Have you thought about measuring gravity somehow? I played around with cheap body scales, they are pretty accurate if the temperature remains stable.

 

[rijnswand]

Here's a graph of the fridge's power consumtion, calculated from the fridge temperature data (from the tops and bottoms of the data I can see when the compressor has turned on and off, and can that way calculate how much power it uses). The dashed line represents what I think is the normal power consumption, when there is nothing inside it that generates heat.
You can see it took about 36 hours for the fermentation to start, and now after seven days the main fermentation process has almost finished. Of course, the beer isn't finished yet, I'll raise the temperature a bit and the fermentation will slowly continue.