Roll Up Your Sleeve, Watch A Video With This Smart Watch Forearm Projector

We’re all slowly getting used to the idea of wearable technology, fabulous flops like the creepy Google Glass notwithstanding. But the big problem with tiny tech is in finding the real estate for user interfaces. Sure, we can make it tiny, but human fingers aren’t getting any smaller, and eyeballs can only resolve so much fine detail.

So how do we make wearables more usable? According to Carnegie-Mellon researcher [Chris Harrison], one way is to turn the wearer into the display and the input device (PDF link). More specifically, his LumiWatch projects a touch-responsive display onto the forearm of the wearer. The video below is pretty slick with some obvious CGI “artist’s rendition” displays up front. But even the somewhat limited displays shown later in the video are pretty impressive. The watch can claim up to 40-cm² of the user’s forearm for display, even at the shallow projection angle offered by a watch bezel only slightly above the arm — quite a feat given the irregular surface of the skin. It accomplishes this with a “pico-projector” consisting of red, blue, and green lasers and a pair of MEMS mirrors. The projector can adjust the linearity and brightness of the display to provide a consistent image across the uneven surface. An array of 10 time-of-flight sensors takes care of watching the display area for touch input gestures. It’s a fascinating project with a lot of potential, but we wonder how the variability of the human body might confound the display. Not to mention the need for short sleeves year round.

Need some basics on the micro-electrical mechanic systems (MEMS) behind the pico-projector in this watch? We’ve got a great primer on these microscopic machines.

35 thoughts on “Roll Up Your Sleeve, Watch A Video With This Smart Watch Forearm Projector

  1. Karl Guttag has also good debunking on these picodisplay watches:

    Basically, there are so many problems with this projector-in-a-watch concept that it will not be a practical solution for anything:

    – Insufficient light output, especially when used outdoors in sunlight (notice how they conveniently tested outdoors out of sunlight)
    – Battery life – watch that is dead after an hour of use is of not much use. LumiWatch claims up to a day of “occasional use” – given that the watch doesn’t have any other display, only the projector, that’s quite a problem.
    – Problems with optics required to get a reasonable image on curved surface (hand) from a very short range and difficult angle
    – Large and cumbersome because otherwise there is simply no space left where to stuff the battery & the optics. Even if you use lasers (as the LumiWatch does) and not e.g. DLP, you still need to elevate the laser above the hand in order to produce a somewhat usable image. (“Our prototype measures 50x41x17 mm, nominally larger than the production 42 mm Apple Watch Series 3 (43x36x11 mm). ” – that’s a brick of a watch …)

    The LumiWatch doesn’t solve any of these problems plus they are also outright lying about being the first to show something like that in a “commercially viable form factor”.

  2. “First, the hardware is designed to elevate the projector as
    high as possible without wasting space. To do this, we
    made the projector the top most component in our watch,
    allowing the aperture to lie 13 mm above the surface of the

    doing it wrong :)

    make the bottom surface of the “roof” a mirror, such that the projector appears to shine from higher

  3. another issue:

    to the extent that you have a dark skin, visibility will be lower

    to the extend that you have a fair skin, and the display is expected to be visible in bright sunlight, you will be projecting light equivalent to multiple suns if you want to maintain contrast, the blueish violet might cause skin cancer in a neat rectangular patch, for a prolonged period of time, unless the color gamut is poor on the blue corner

    people with who’s skin browns substantially in response to the blueish light wlll develop a patch of darkened skin (the opposite of bikini shadow effect)

    1. Agreed. I guess it’s one of those youtube monetizing things, I’ve seen this being done before several times, always the fake video and the social media buzz that gets views and thus cash.

    2. The concept videos are fake, and are taken from scams. The Carnegie-Mellon device that that’s shown later in the video is an improvement on a real existing device. It, like similar products, is probably dependent on batteries with higher energy densities than are available for commercial use, but the projection and touch-sensitivity abilities on display are reasonable.

      The notable difference between real and fake devices is that real devices can’t project black. Anything that’s dark in the original image will be flesh-tone in the projection. Maybe a bright blue. That’s how you could tell that the concept devices (again, taken from Kickstarter scams) were bad fakes.

  4. Hmm, I’m wondering whether its actually not more sinister, another fresh round of capital going to be syphoned off the same people that also supported the Geeny bracelet.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.