Android seems to be the key mobile operating system and now it aims for the same status on smaller wearable devices. It sounds innocent enough, but this could be the change that the market needs to make smart watches a commonplace reality.

Android Wear is in developer preview at the moment, but it is safe to say that it hasn't just appeared from nowhere. It seems to be based on the version of Android used in Google Glass - which is, of course, a prime example of a wearable. You can think of it as a generalization of the OS that Glass uses. As such it is a fairly obvious move on Google's part, but it still deserves to be regarded as a smart move. 

The basic application model uses "cards" that provide simple I/O and a sort of flow of control. The cards present data to the user obtained from a remote server accessed via an associated mobile phone.  The user is expected to interact with the device using voice input more than touch.

A key innovation is the use of activity detection APIs to allow devices to wake up only when the user might make use of them. For example, a watch could be in sleep mode until the user raises their wrist to read the dial when it could switch on. The activity API can also be used to monitor what the user is doing and record their activity level for "lifestyle" apps. 

Google makes four claims for what the device can do for you: 

• Useful information when you need it most. Android Wear shows you info and suggestions you need, right when you need them. The wide variety of Android applications means you’ll receive the latest posts and updates from your favorite social apps, chats from your preferred messaging apps, notifications from shopping, news and photography apps, and more. 
  
  
• Straight answers to spoken questions. Just say “Ok Google” to ask questions, like how many calories are in an avocado, what time your flight leaves, and the score of the game. Or say “OK Google” to get stuff done, like calling a taxi, sending a text, making a restaurant reservation or setting an alarm. 
  
  
• The ability to better monitor your health and fitness. Hit your exercise goals with reminders and fitness summaries from Android Wear. Your favorite fitness apps can give you real-time speed, distance and time information on your wrist for your run, cycle or walk. 
  
  
• Your key to a multiscreen world. Android Wear lets you access and control other devices from your wrist. Just say “OK Google” to fire up a music playlist on your phone, or cast your favorite movie to your TV. There’s a lot of possibilities here so we’re eager to see what developers build. 

The final point seems to suggest Chromecast integration, which of course would be easy via the associated phone. 

If you would like to see how Google thinks a smart watch might sell to the public try the following video:

Somehow I think the reality might be a lot more frustrating than the video suggests - try voice recognition in a crowded street with lots of traffic noise. I think holding you watch near to your mouth is likely to be a commonplace sight. 

A more down to earth look at the developer preview still concentrates on the smart watch idea:

The developer preview works with a standard Android SDK-based development set up - either Eclipse or Android Studio and you can test applications using the Android emulator - and there are both square and round screen devices available. You can get the Developer Preview by just signing up and waiting for an email to provide you with access to a zip file. 

While others have been experimenting with the difficult problem of creating a smart watch from hardware through software, Google has left the hardware to others. Although it has to be said that Motorola, which Google sold to Lenovo, seems to be keen on the idea and has produced some hardware - the Moto 360. The Moto 360 is special in that its round like a real wrist watch and looks more like one than most things we are being asked to strap to our wrists. 

Overall the idea of an operating system that we all know working on a range of wearables from a range of manufacturers seems like a lot safer bet for the programmer.