therm

A Raspberry Pi thermostat control app

Install

On the raspi you'll need libblas before installing scipy:

sudo apt-get install libblas-dev libatlas-base-dev rpi.gpio

This project uses python 3. It's recommended that you use virtualenvwrapper. On raspbian, do:

sudo pip3 install virtualenv virtualenvwrapper

Add the following to ~/.bash_profile:

export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

Then:

mkvirtualenv therm
workon therm

Then install python requirements:

pip install -r requirements.txt -r requirements-device.txt

This will probably take a while (1-2hr on a RasPi zero); some of the requirements do not have wheels available for raspi, and therefore will be built from source.

To run the tests (requires python 3.6, specifically for assert_called_once):

pip install -r requirements-test.txt
pytest

Configuration

Therm uses a database to store temperature observations and thermostat state. Any DB that SQLALchemy can talk to works. To configure your DB, set the following environment variables (or handcode them in therm.settings if you're feeling bold):

export THERM_DB_URL=thermdb.cln2j9a8fio32eu.us-east-1.rds.amazonaws.com
export THERM_DB_UNAME=thermuser
export THERM_DB_PASS=correct-horse-battery-staple

If you want to send status messages to SQS using flask poll --to-sqs, you'll need to configure boto3.

Per-device hardware config

Run

The full thermostat consists of three processes: a polling loop, a web server, and a browser displaying the web UI on the raspi screen.

To start the polling loop:

FLASK_APP=therm flask poll

The polling loop reads the temp sensor and write samples to the DB. It also looks at the latest State in the DB, and if the state represents a thermostat "hold" temperature, it will enable/disable the heat relay.

The polling loop also handles button presses (TODO: explain State)

To start the web server:

FLASK_APP=therm flask run

To start Chromium in 320x240 kiosk mode on display 0:

./kiosk.sh

Testing

Running any of this in an environment without the raspberry pi library (e.g. your laptop) will fallback to fake-rpi, which provides fake sensor inputs and GPIO outputs to the program, as well as dumping debug information to the console.

Shell

Jupyter is included in test requirements, see https://blog.sneawo.com/blog/2017/06/27/how-to-use-jupyter-notebooks-with-flask-app/ for how to import your flask app into a jupyter notebook (and for some reason use docker if you want.)

Autostart on raspi:

I currently have two devices: a raspi Zero without a screen running the relay and temp sensor, and a raspi B+ with a 2.2" screen running the web UI and buttons

To run the web UI on startup on the b+, add to /etc/xdg/lxsession/LXDE-pi/autostart:

@/bin/bash /home/pi/devel/therm/run_kiosk.sh

To run relay and sensor on the zero, add to /etc/rc.local:

su pi /home/pi/devel/therm/run_temp.sh

In this setup, there are no buttons (pi B TFT hat has buttons, but they run in poll loop, so not enabled in this mode.)

To run everything on a single device, add to /etc/xdg/lxsession/LXDE-pi/autostart:

@/bin/bash /home/pi/devel/therm/run_all.sh

uWSGI + nginx

Install nginx and uwsgi globally (make sure you're using python 3 install!):

sudo pip3 install uwsgi
sudo apt-get install nginx

Add your site config in /etc/nginx/sites-available/therm.conf:

server {
	listen 80;
	server_name pi.local;

	location / {
	    include uwsgi_params;
	    uwsgi_pass unix:/tmp/uwsgi/therm.sock;
	}
}

Create a systemd service for uwsgi in /etc/systemd/system/uwsgi.service

[Unit]
Description=uWSGI instance to serve therm

[Service]
ExecStartPre=-/bin/bash -c 'mkdir -p /tmp/uwsgi; chown www-data /tmp/uwsgi'
ExecStart=/bin/bash -c 'cd /home/pi/devel/therm; source /home/pi/.virtualenvs/therm/bin/activate; uwsgi --ini uwsgi.ini --logto /var/log/therm.log'

[Install]
WantedBy=multi-user.target

Test it:

sudo systemctl start uwsgi

Launch nginx and make sure everything's working:

sudo service nginx start

If everything works, you can have nginx and uwsgi launch on boot:

$ sudo systemctl enable nginx
$ sudo systemctl enable uwsgi