Smartphones use big touchscreens on the front as a useful tactile interface. However, our hands naturally wrap around the back of the phone, too. This area is underutilized as an interface, but the designers of BackTrack found a way to change that.
The idea is simple. The project video notes that conductive tape can be placed on a multitouch touchscreen, allowing touches to be read at a remote location. Taking this concept further, BackTrack works by creating a 2D matrix on the back of the phone, and connecting this matrix to a series of pads in a row on the front touchscreen. Then, touches on the back touchpad can be read by the existing touchscreen on the front screen.
Doing this in practice requires the use of fancy transparent electrodes and flexible connections. However, the team behind Backtrack were able to create their passive rear touchpad in a formfactor that fits into a simple phone case. It can then be used to play games or use interface with the phone in other ways.
We fully expect phone manufacturers to start creating interfaces that use the back surface of the phone. Apple have already explored this with the rarely-discussed back-tapping feature. Implementing a full 2D touchpad on the rear could quickly become a great point of difference for the first handset manufacturer to get it right. Video after the break.
[Thanks to Itay for the tip!]
Interesting! The Motorola Backflip had a similar feature. It could be used to things such as scrolling through documents.
Google Pixel phones allow you to use the back fingerprint reader to scroll or do other actions.
That’s the one feature I miss on that phone.
TapTap makes the feature available for any Android 7.0+ device with its port of the double tap on back of device feature from Android 12. Not only that feature but 50+.
That phone was truly peak product design coupled with cheapest hardware and lazy software.
Oh yees! And also extend it to the edges as well!! Everything you touch is a interfarce! Great idea! Briliant! We absolutely need more buttons on our phones. Who holds their phones anyways? Maibe just waving your hand could also be used. Pure magic!
Another one of the secretive League Of Undercover Sadists who also invented conditional interfarces and zoning rules.
This could be a useful accessibility feature though.
A lot of the smartphones with rear fingerprint sensors had similar features. Notably, I could swipe down on the sensor to open the notification shade. This solves a big UI problem with phones – if cell phones are getting taller, how can you expect people to to reach all the way up there to access one of the most common functions? (You might say they shouldn’t be getting taller, but in any case it’s an inconvenient gesture to do one-handed).
I had an original Pixel XL. The sensor is quite unmistakable and just a little out of the way of where your fingers actually rest. It’s actually quite a convenient input device, and I often accidentally found myself trying to use it for unsupported tasks like scrolling or flipping between pages of a UI.
Just because you cannot afford microgravity doesn’t mean it’s a bad idea.
You actually made me think about this.
I like the idea for emulation for SOME buttons but not all.
I like the thought of scrolling without blocking half my view.
I do handle my phone quite a lot and whilst I can see the wires on the side being covered so they don’t register touch I can also see the wiring going over the top because on reflection I practically never handle my phone on that section. Or even being integrated into a case so it can be purpose built and used.
I remember (and miss) my Nokia 6700 having a similar back tapping feature where phone locked and screen off you gently back tapped twice and the screen would display the time. Very useful and nicely designed feature. It only requires an accelerometer and I’d love to see that implemented as default on modern Android phones (baked in the OS).
My oppo (android 12) essentially does this, with the “always on” display. it isnt always on, but bump or tap thephone and the clock is displayed on the front screen. I assume its somewhat standard feature?
Interesting. I have access to multiple Android devices right now (from 2010 to 2020) and none of them seems to have this option so I guess it’s a proprietary one
Samsung galaxy have this as well. My S9+had it and my S22 has it. Or you can set it to tap the screen twice and it does the same thing.
an AMOLED screen is a mandatory first element for AOD operation. an LCD has to run a backlight to display anything at all, so it’s always generating full light output across the entire screenspace (notwithstanding Zoned Backlight, which is better but still imperfect for the job), which then has to be gated by Off Pixels. OLED screens only generate light from On Pixels, so the power demand of an AOD is (ideally) linearly proportional to the Total Screen Luminance
The Pixel 6 (and possibly other Android 12 devices) have IMU-based back-tapping baked in as a remappable input, as well as capacitive front-tapping to wake the display.
Brain interface please
So, by touching your bald spot, I can control your actions?
I saw something like that in the movie “Ratatouille”.
B^)
I wish I had transparent fingers.
The feature I truly miss is the 5-way wheel on the side of the SE P910
Yes! the jog wheel, that was intuitive (I still have mine somewhere, must try it again).
I’m certain this technique could be adapted to add a thumbwheel control to any phone. The sucky part is the ITO cost but in theory you could use copper foil on the very edge of the screen as well.
To be honest, I think I’d kind of love a thumbwheel to scroll on my phone.
PlayStation Portable had the exact same feature, it was used only in two games IIRC.
I think you mean the ps vita. Funnily enough I got a beat up vita for cheap with a damaged rear touch ffc and I just never bothered fixing it because like you said the rear touch isn’t required for the majority of games.
Assuming modestly high resolution(which might not be possibly just by hijacking the front screen; but could certainly be implemented as a peripheral connected to the phone in the worst case) this seems like it would be absolute catnip to the people who can adapt to weird input devices.
Normal people are wasting a third or so of the screen on a soft keyboard to poke at with their thumbs; those guys are merrily chording away at absurd speed by tapping on the back of their phone…
If you are going to really ‘type’ even by chording I expect you’d want something tactile to actually let you hit the right combinations with confidence – you can’t do touch typing like speeds if you are waiting for the letters to pop up, and they get seen and processed as reading exactly as you expected to be sure your fingers are on the ‘home row’ – you should be half way through the next word at least before you can really pick up on the bum letter, as you fingers are already moving on, and your focus aught to be on what you are composing or copying not if your hands successfully hit did the job blind…
I’d think having a raised bump that isn’t sensitive (or at least not used when play as ‘keyboard’ sensitive), so you can rest your fingers on that known position for referencing your chording by touch… Or just make it simple and have actual physical button.
Either way I agree there is a method that would give a great deal of screen real estate back getting rid of the keyboard with this sort of concept, at least for some folks.
Still not sure its really worth it though – at some point you want to accept that a mobile isn’t a real general use computing device, as even with the best will in the world the screens are too damn small to hold enough information (even when you still have good sharp vision). The use for anything that really needs screen the keyboard’s screen real estate back is probably a job very much for a laptop sized screen or better.
More ways to accidentally pocket dial people.
Ever since I played that one Welcome Park minigame on the PS Vita, I’ve always wondered when a phone manufacturer would need a new and fancy back cover to stand out from the rest and put a trackpad on the back.