We might have seen digital blinds before, but Sonte's on-window film, deep within is pitched at home-owners rather than business signage. The switchable film is a thin, light layer that can be retro-fitted to existed windows and the company reckons it's so easy that you should even be able to do it yourself. We saw the film used both as a picture display and as a see-through panel that can be made frosted -- as you can see above in our before-and-after. To control how it looks, you'll need to install either the Android or iOS app, where there's controls for multiple smart films. Another use posited was transforming large windows into a projection screen. That extra layer to your windows will also notch up savings on your heating bills too -- at least according to Sonte. The product is still in development, so you won't be able to pick up Sonte's adjustable film yet, but the company looks likely to approach crowdfunding sites to help get its switchable film tech off the ground.