(Last updated: June 2014. See last step for details on changes.)
This is the UDS Digital Supervisor, an Android app and hardware for remotely maintaining the temperature of your UDS like a thermostat. Your phone monitors the temperatures inside the UDS and adjusts a blower to keep the temperature to the setting you decide. Don't have a UDS? You can build one yourself!
The Supervisor app has the following functionality:
- Maintains a constant temperature inside your smoker (duh).
- Sounds an alarm if a thermometer temperature falls outside a configurable range. Very handy for overnight cooks so you can sleep worry-free.
- Records the temperatures in a database and displays a graphical chart showing the progress of your cook.
- Periodically tweets the status of your smoker so you can monitor your cook from anywhere in the world. Requires an internet connection (double duh). If you need something to put yourself to sleep you can follow my smoker's twitter account.
- A companion app running on another Android device can monitor the Twitter feed and sound an alarm if there is an error. Go see a movie in peace knowing that your smoker is purring like a kitten in a basket full of warm socks.
- Can monitor up to eight thermometers and measures in Fahrenheit, Celsius, or Kelvin.
The app monitors the temperature using thermometers inside your smoker and compares it to your target temperature. If the temperature is too low the app will turn on a blower to force more air into the UDS, which will stoke the coals and increase the temperature. The app uses a PID algorithm to determine when to turn on the blower. Your phone uses Bluetooth to communicate with the hardware attached to the blower and the thermometers.
This project is made up of three main parts:
- Blower The temperature of the smoker is ultimately determined by the amount of air the coals get. The more air the blower pushes into the smoker the hotter it will get.
- IOIO controller The IOIO (pronounced yo-yo) is a microcontroller specially made for Android and acts as the connection between the blower/thermometers and the Android app. The blower and thermometers plug into the controller and it sends signals to your phone using Bluetooth. Check out the IOIO home page for more information.
- Android app The app monitors the thermometer temperatures and adjusts the blower speed accordingly by sending a signal to the IOIO controller. The app uses a PID algorithm to determine the correct blower speed. The temperatures and the blower speed are recorded in a DB (database) which can then be used to display a chart of the entire cook. The app is free to download and is Open Source, which means it will always be free.