This project aims to develop a multi-sensor (up to 8) temperature process control platform with configurable heating/cooling actuators and remote host access/monitoring.
The process controller is called fresca-controller and is based on an Arduino platform and the DS18B20 and/or DHT22 digital sensors. It supports setting temperature operating point with hystheresis via an LCD Keypad shield, and supports temperature display with additional 7-segment displays for each sensor. The controller will turn on/off the heating/cooling actuators according to configurable temperature thresholds for each sensor.
The host handles connection to the controller using fresca-link (UART) and provides remote access to the controller via fresca-webapp. It is usually run on a single board computer like a Raspberry Pi.

fresca-controller:

• +-0.5deg celsius accuracy from -10deg to +85deg without calibration (Higher accuracy is possible through offset calibration) (DS18B20)
• Relative humidity sensing with DHT22 sensor
• Interactive menu to modify sensor/temperature control parameters
• Monitoring of temperature for each sensor on 7-segment displays (Celsius/Fahrenheit)
• CoolOn/CoolOff and HeatOn/HeatOff thresholds offer hysteresis-like temperature control for each sensor
• Offset calibration for each sensor, stored in the DS18B20's EEPROM (each sensor will store the calibration data)
• Storage of project settings in Arduino's EEPROM
• Sensor CRC and presence checking (no wrong read-outs)

fresca-link:

• Data-gathering from controller via UART-link
• Logging of controller variables to disk (Time/Temperature/Humidity/Controller state)

fresca-webapp:

• Remote monitoring via webapp (python/flask based using Google Charts)

fresca-controller parts:

• Arduino Mega 2560 or similar (depending on how many processes are needed)
• DFR Robot LCD keypad shield for user interface/control (one)
• DS18B20 digital temperature sensor with OneWire interface (as many as processes are)
• DHT22 digital temperature/humidity sensor (as many as processes are)
• 7-segment displays based on TM1637 controller (as many as processes are)
• 5v Relays as actuators (as many as processes are)

fresca-link and fresca-webapp parts:

• Host computer with internet connection (Raspberry Pi, PC or other)
• A fresca-controller

• PLEASE NOTE: This repo contains submodules, so for the first time cloning the repo you can do it like this: git clone --recursive https://github.com/lcapossio/fresca.git , or if you already cloned you have to initialize the submodules: git submodule update --init --recursive. Also each time you pull, you have to pull recursively, in case there is an update for the submodules: git pull --recurse-submodules
• Although this project was first started to aid in beer fermentation, it can be used in any temperature control project that has similar specifications
• Source code is released under GPLv3, please read LICENSE for more information

PD: The project is called 'fresca' in reference to Argentinian slang word used to describe a cold beer! Plus direct-translation of fresca is cool :)