Stataway is a service that runs in your home, determines if anyone is in your home, and sets your thermostat to its "home" or "away" mode accordingly.
The service enables laziness for those who forget to manually set their thermostat to "home" or "away", but it does not get in the way of doing so. If you are paying the bill at a restaurant and use a mobile app to set your thermostat to "home", this service will not "fight" your state change.
Put another way, as with all good home automation, this service endeavors to be helpful without being a dependency or getting in the way.
In addition to the detector-specific and thermostat-specific settings below, these configuration settings may be set as environment variables:
HOME_LATITUDE: latitude of your home location in decimal format
HOME_LONGITUDE: longitude of your home location in decimal format
The only supported thermostats currently are those made by Venstar and that support its local API.
Support for additional thermostats is desired. Please be in touch if you would like to assist in adding one.
VENSTAR_URL: URL to the thermostat's API
Whether anyone is in your home is determined by "detectors". Currently there is only one detector, but the system is designed for multiple.
A detector sends a "trigger" notification when it believes the state should change from "home" to "away" or vice versa. Those notifications get received by a control loop that determines if and how to make a change to a thermostat's state.
This detector uses Google location sharing to determine if someone is close enough to your home for the thermostat to be in "home" mode. It polls for the locations every 30 seconds.
The detector uses two distances to determine when to send a trigger. When changing from a state where any shared location is inside the outer shell to a state where all shared locations are outside the outer shell, a trigger is sent for the "away" state.
After this detector has triggered "away", it waits for at least one location to appear within the inner shell before triggering "home".
Having the inner and outer shells helps avoid thrashing between the two states in a case where someone was near the boundary in a single-shell design.
What distances you choose will depend on your normal travel habits, and when you want your thermostat to change states. Early testing has used .7 and .5 km. Those distances are good enough to cause the thermostat to go to "away" most of the time when the house is unoccupied for an hour or more. But the distances are small enough that the service rarely notices that occupants are close to home until they are actually at home, so it does not give the HVAC an opportunity to pre-condition the space.
In practice, it seems that when a device first connects to the wifi network at home, that causes the device to report a location change. That is usually good enough for your system to engage heating or cooling before you make it inside, but only by a minute or less.
- Create a new Google account only for this purpose.
- Have every person whose location you want to consider share their location with that new account through Google Maps.
- Set the below environment variables when running stataway.
GOOGLE_USERNAME: The full username for a Google account, usually an email address.
GOOGLE_PASSWORD: The password for the account.
GOOGLE_INNER_KM: The inner shell distance in kilometers, decimal values supported.
GOOGLE_OUTER_KM: The outer shell distance in kilometers, decimal values supported.
No, we haven't figured out how to detect the future. These are ideas for detectors that could be implemented in the future.
Owntracks could be used as a location source similar to Google. It has privacy advantages. It also is meant to be integrated with, as opposed to Google location sharing data that we have to scrape from an undocumented API.
A downside is that you may need to provide a service that listens on the Internet for devices to report location changes.
A detector could look for the presence of devices on the local network.
Depending on how this gets implemented, it can be a bad idea to ping mobile devices repeatedly and regularly, because it can prevent them from staying in a power-saving mode. If polling for their presence, it should only be done while the current known state is "away", and should be used to detect the arrival of a person at home. Other detectors could then be used to determine when to change from "home" to "away".