Home Assistant is an awesome open-source home automation platform, with a strong focus on privacy, offering integrations for more than 1000 smart home components. The project puts local control first, and empowers you to run it on your local server.
IOTA is an open-source distributed ledger, built to power the future of the Internet of Things with feeless microtransactions and data integrity for machines. You can also run it on your own server — and 1000s of people, possibly far more, — including this author — , do so.
Integrating those two technologies would immediately enable many more possible applications. Without thinking for too long, the following examples came to my mind:
Reacting to events in the Tangle
Your smart home solution is supposed to run on a small device, like a Raspberry Pi, in your home. But there will come a time you want to be able to trigger actions from outside that home.
An example for this could be some mailman, who wants to unlock your front door to deliver mail. Or an AirBnB host, who temporarely grants a guest access to his home. Or just a friend, who you otherwise would give a physical key.
For this, you could expose your Home Assistant server to the internet, but this comes with its own risks. Combining Home Assistant with IOTA elegantly solves this, eliminating all security concerns.
Your mailman, guest, or friend would have to publish this “open door” action on the Tangle, digitally signed so you could afterwards undeniably prove the open door was a direct result of this message. The message also has to be encrypted, so no one else can find out when guests come to your apartment — or when it is unoccupied.
Audit trails in the Tangle
As initially stated, IOTA is great for ensuring data integrity. This is where the following use case comes from: Audit trails.
Certain changes of the state can be published to the Tangle, to prove afterwards that the data is pure and unaltered.
These state changes could be simple, like movement detectors, that triggered an alert; or more complex scenarios like temperature sensors which regularely publish their values to ensure the cooling chain of a food supplier is unbroken.
The raw data can either by encrypted, so only the owner of the corresponding private key can understand it (and, if needed, reveal it to third parties like lawyers or courts), or it can deliberately be open and for the whole world to see.