Overview of options available for Mobile app development primarily from Hybrid app development
Google has recently released the Android Things developer preview SDK. Android Things is Google's Internet of Things(IoT) platform formerly known as Brillo. If you know how to develop an Android app, you can use this SDK to build your own IoT apps.
This SDK supports the Raspberry PI3 which is one of the most popular system on chip boards and also has lot of PI hats that can extend the functionality. Also the GPIO ports in the PI allow you to connect various electronic components and program them to do anything that you like.
To get started with this, you will need a Raspberry PI3. You can download the ROM to be flashed on the to the PI here. The detailed steps to connecting it to your computer and flash the device are present here.
I think this a great move from Google to standardise the IoT platform. Google is already trying to enter into the Home automation and entertainment segment with Android TV, Chromecast and their new Google Home assistant. Providing a developer preview and providing support to a popular prototyping device like Raspberry PI3 would allow developers to experiment and ideate quickly. This brings in endless possibilities and new line of products.