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Create pretty charts of your Nest thermostat data
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inc
README.md
collect.php
dbsetup
fetch.php
index.html
insert.php
test.php

README.md

nestgraph

Create pretty charts of your Nest thermostat data. Instead of using the unofficial nest_api, the official one is used.

Background

The point of this project was to see how well the Nest algorithms work. In particuar, the Nest claims to minimize overshoot, which is a common problem with cast-iron radiators. It also claims to know when to start heating in order to hit your target temperature exactly at the time you scheduled it.

Unfortunately, you can't actually access historical temperature data on the Nest website or via the iOS app. It shows you when heating was turned on/off and what the temperature targets were at those times, but it doesn't give you any indication of how well or how poorly the thermostat performed. This could be by design, as it's a lot of information to store.

This project uses an unofficial Nest API to pull your temperature readings periodically and store them in a database so that you can inspect the data yourself in an easily consumable form.

I also wanted an excuse to play with the D3 (Data-Driven Documents) library a little.

Features

  • Polls Nest website to collect thermostat telemetry
  • Stores selected data in local MySQL database
  • Generates a nice visualization of actual temp vs. set point
  • Lower mini-chart is interactive pan-and-zoom of the upper chart
  • Hover over the gray circles to get the exact timestamp and temperature

Dependencies

  • LAMP stack

Getting Started

Clone this repo into your web root.

cd [your-web-root]
git clone https://github.com/lubao515/nestgraph.git

Open inc/config.php in a text editor and update the nest_token (For more detial to get nest access token see here). Update the local_tz variable to reflect your time zone.

Run the test script to make sure that the API is able to pull your thermostat data correctly from nest.com.

php test.php

If this works, you should see a bunch of stuff fly across the screen, ending with something like this:

Heating             : 0
Timestamp           : 2013-01-15 22:10:39
Target temperature  : 67.00
Current temperature : 67.53
Current humidity    : 29

Choose a password for your local MySQL nest database, and update it in two places: inc/config.php (the db_pass variable) and dbsetup.

As root or using a DBA account, run the commands in dbsetup to create the MySQL database that will be used to store historical data.

mysql -u root < dbsetup

Create a cron job to poll the website periodically and update the local database. The thermostat does not phone home on a fixed schedule, but typically it updates in 5 to 30 minute intervals. The script will only insert into the database if there is new data available. Obviously, update the path to insert.php if it's not in /var/www/html/nestgraph.

NOTE: if you have it calling every 5 mins NEST will put a stop to it and stop allowing connections. If this happens stop the updater for a few days and start it back up with a wider interval.

*/5 * * * *     /usr/bin/php /var/www/html/nestgraph/insert.php > /dev/null

Point web browser to the nestgraph directory on your webserver! Admire pretty graphs (actually, they won't be all that pretty until it has collected some data).

This version has

  • Current temp with a curved line
  • Heating On/Off
  • Cooling On/Off
  • Fan On/Off
  • Humidity %
  • Auto/Manual Away
  • Leaf (indicated by a bump)

Known Issues

  • need to figure out how to make curved lines for the other reportable data elements.
  • Only supports a single Nest thermostat from a single home. If many, the first one will be shown.
  • Heating on/off trendline lazily mapped on to the temperature graph
  • Assumes you want temperatures displayed in Fahrenheit
  • Doesn't automatically redraw when you resize the browser window
  • Labels (current/target/heating) don't follow the trend lines when you pan/zoom
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