pi-tilt

Tools for reading your Tilt hydrometer on a Raspberry Pi, storing the results as CSV, and mailing you summaries and plots. Intended for use as two cron jobs (recording data and mailing plots).

TODO

• plot: detect missing file and send sensible message

Dependencies

• python bluez, matplotlib, pandas

  • sudo apt-get install python3-bluez or pip3 install PyBluez

• Make the bluetooth interface accessible without being root:

  • sudo setcap cap_net_raw+eip /usr/bin/python3.7 (for example)

  • Note: this command does not follow symlinks so applying it to /usr/bin/python3 won't work

  • You need to run this command whenever apt updates that library

• A working /usr/sbin/sendmail command is required (nullmailer is sufficient)

crontab examples

• The same config file is used for both.

15 *     * * *  path/to/pi-tilt/record.py -c path/to/config.json 
00 09,21 * * *  path/to/pi-tilt/plot.py -c path/to/config.json

config file

required items

• hydrometers: map of Tilt colors to CSV filenames (absolute or relative to the directory the config file is in)

• readings: number of readings to take (then record the median of the density and temperature readings)

• wait_seconds: interval between readings

• give_up_minutes: quit after this amount of time

• mail_from: e-mail address

• mail_to: list of e-mail addresses

optional item

• water: SG reading in water after changing the battery (for recalibration); if absent, a default of 1000 will be used

Acknowledgements and notes

• Derived from https://github.com/atlefren/pytilt and updated to Python 3

• The code in blescan-py is adapted from https://github.com/switchdoclabs/iBeacon-Scanner-

• The Tilt UUID-to-color mapping is taken from: https://github.com/tbryant/brewometer-nodejs

• https://kvurd.com/blog/tilt-hydrometer-ibeacon-data-format/

• https://tilthydrometer.com/