Powered by three AA batteries that should reportedly last for up to a year of use, FloSmart is simply clipped onto the frame of an existing air filter, and connected to your home Wi-Fi.
As long as the filter remains relatively clean, forced air flows straight through it, bypassing the FloSmart. Once contaminants such as dust and pollen start to accumulate in the filter, though, it gets more difficult for air to pass through it. This means that the air is increasingly forced to go through the FloSmart, bending a small hinged flap within it. Basically, the more the flap bends, the dirtier the filter is becoming.
More specifically, the FloSmart utilizes opposing magnetic force and linear hall effect sensors to measure the bend of the flap. Readings are stored on an onboard processor, and periodically transmitted to an online server for analysis. When that server determines that the filter needs replacing, it notifies you via an iOS/Android app. That app can then be used to order new filters for home delivery, plus it lets you know when the FloSmart's batteries are getting low.
If you're interested in getting a FloSmart, it's currently the subject of a Kickstarter campaign. A pledge of US$25 will get you one, when and if they reach production. The planned retail price is $50.
According to newatlas