Brewing Sensors via ESP32 to MQTT and ELK

Author: Arthur Kepler for Oort Cloud Brewing (our brew collective)

Date: Published October 11, 2020

Description

This set of two sensors, which share a breadboard with an ESP32 devboard, captures temperature, humidity, and gas pressure, reporting it back to an MQTT and ELK stack server.

The pressure sensor is connected to a tee fitting between the CO2 tank and the keg.

Requirements

Hardware

• A small breadboard and about 60cm (2 ft) of wiring
• ESP32 dev board (PIN comments are for NodeMCU32 dev board) (https://www.amazon.com/dp/B0718T232Z)
• DHT11 Temperature sensor (https://www.adafruit.com/product/386)
• 60psi 5v-in/4.5v-out pressure transducer. 60 is a good upper bound for brewing with nitro, 1/4" is good for gas line fittings. Amazon does not have these, most US OEMs charge > $120. I recommend eBay or Google Shopping. (https://www.google.com/search?q=pressure+transducer+60+psi+5v&tbm=shop)

Software

• Arduino IDE (or your favorite IoT IDE, etc.)
• MQTT broker on a host server (Tested with Mosquitto)
• Python3 (Tested on v3.5) on host server
• ELK Stack (Optional) (index export needs 6.5+, Kibana Viz export needs 7.3+) It's easy to recreate the index and visualization without importing my .ndjson export.

Arduino Libraries

• Wifi by Ardino
• PubSub Client by Nick O'Leary (Arduino Client for MQTT) (https://pubsubclient.knolleary.net/)
• DHT-sensor-library by Adafruit

Pip Modules

pip3 install paho-mqtt
pip3 install elasticsearch

Components

1. arduino-ide-code/brewing-sensors.ino: Arduino C++ code, tested and uploaded via Arudino IDE
2. ELK/mqtt-to-elasticearch.py: Python script to read from MQTT and publish to Elasticsearch
3. ELK/kibana-chart-export.ndjson: Export of Kibana saved-objects for the oort_sensors-*

Install Notes

Update brewing-sensors.ino with your WIFI and MQTT server config.

Optionally change references of oort_sensors-* to an ELK index name of your choosing.