Cloud-enabled Bathroom Scale

Cloud-enable the EB9121 bathroom scale with an LIRC receiver.

The EB9121 bathroom scale transmits weight measurements to a remote display unit using infrared. The infrared protocol was reverse-engineered and is thus able to be interpreted using this script. This script logs measurements to a Google Docs spreadsheet for graphing/exporting.

This script uses the oauth2client library to authorize access to Google Docs, and the gspread library to interact with Spreadsheets on Google Docs. Note that oauth2client does NOT support Python 3.

Installation

The installation process for this script is rather involved because of the OAuth 2.0 access to the Google Docs spreadsheet.

Steps 3 & 4 is a one-time process of creating a Client ID for this script. I could supply the one I created, but I'm worried of abuse, so you will have to do this yourself.

Step 5 is the similar to the setup required for the Adafruit tutorial for humidity logging.

Steps 6 & 7 verify that the setup is working as expected.

1. Clone the repository:

    hg clone https://bitbucket.org/geekman/cloud-bathroom-scale
   

2. Create the virtualenv to download required the Python dependencies. If your system has both Python 2 and 3 installed, you might need to use virtualenv2 instead.

    cd cloud-bathroom-scale
    virtualenv venv
    source venv/bin/activate
   

3. Run the mkwheels script to download dependencies and unpack them into the deps directory:

    ./mkwheels
    unzip -d deps deps.zip
   

4. Now the virtualenv is no longer needed. You can now deactivate and discard it:

    deactivate
    rm -rf venv
   

5. Expose the lirc device by adding a dtoverlay to /boot/config.txt:

    dtoverlay=lirc-rpi,gpio_in_pin=4
   

6. Create a project and a new Client ID at the Google Developers Console. Select "Installed application" under "Application Type".

7. Download the JSON file for the generated Client ID. Ensure that the filename is client_secrets.json.

8. Create a new Spreadsheet in Google Docs and delete off all the rows. Find the document "key" in the URL, which should look something like this:

    https://docs.google.com/spreadsheets/d/<DOCUMENT_KEY_HERE>/edit
   

9. Run the script to test that it works by passing the --test argument:

    ./cloud-bathroom-scale.py --test <DOCUMENT_KEY>
   

10. Check that a row has been added to the Spreadsheet with the current time.

Normal Usage

The script needs to be started, like so:

./cloud-bathroom-scale.py <DOCUMENT_KEY>

When you step onto the scale, the bathroom scale should emit the measurements via infrared and will be picked up by the script. When the weight is stable, the reading is recorded into the Google Docs spreadsheet.

A status LED can be added to visually indicate to the user if the measurements are being picked up by the IR receiver. The LED blinks to indicate this, and when the weight is being recorded, the LED turns solid for a few seconds, then turns off. The GPIO pin connected to the LED can be specified by the --led argument.

If there are problems, you can pass the --debug argument to see if weight measurements are being correctly recognized.

A systemd service file has been included (tested on Arch Linux) to automatically start the logging script on boot. You will need to copy this file into /etc/systemd/system/multi-user.target.wants/ and modify the Environment= lines accordingly. For "security", the script runs as my user and this can be specified by the User= line.

License

cloud-bathroom-scale is licensed under the 3-clause ("modified") BSD License.

Copyright (C) 2014 Darell Tan

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.