This smartwatch lets you beam your movies onto the nearest wall

Asu Cast One

One of the biggest complaints about smartwatches is that they're not that useful, but that's a criticism which could be harder to level at the Asu Cast One and its built-in projector.

This slightly mad invention spotted by GizChina makes normal smartwatches look small, but if you don't mind having a brick strapped to your wrist, are happy to import it from China and have 2,980 Yuan (around US$455, £311, AU$632) to spare it could become an essential part of your gadget arsenal - if it's any good.

That's a big if, as a projector this small is unlikely to be particularly great, but it certainly looks versatile. Wear the watch and you can project an image onto your hand, or put it in a stand and you can project a much larger image onto a wall or ceiling.

Projecting the future

The projector has a 720p resolution and can project images anywhere from 1.5cm to 2 metres away at a 720p resolution. Potential uses shown off in a video for it (below) include projecting a clock on your ceiling, apps onto your hand, sat nav onto your windscreen or a movie onto a wall.

With a 1.2GHz quad-core Snapdragon 400 processor, 768MB of RAM and 4GB of storage its specs stand up to other smartwatches and its 740mAh battery is almost twice the size of most rival wearables, though it'll need to be if it's going to power a projector. The Asu Cast One also runs Android 5.1, rather than Android Wear.

It's unusual and expensive enough that we don't expect the Asu Cast One will get an international release, but if you're desperate to have a projector built into your tech you may not have to wait too long, as it's a feature of numerous concept devices, such the Lenovo Smart Cast.

That's a phone, not a watch, but its projecting skills and battery life are probably stronger for it.

James Rogerson

James is a freelance phones, tablets and wearables writer and sub-editor at TechRadar. He has a love for everything ‘smart’, from watches to lights, and can often be found arguing with AI assistants or drowning in the latest apps. James also contributes to, and and has written for T3, Digital Camera World, Clarity Media and others, with work on the web, in print and on TV.