Reusing An Old Android Phone For GPIO With External USB Devices

November 4, 2024 by Maya Posch 44 Comments

Each year millions of old smartphones are either tossed as e-waste or are condemned to lie unloved in dusty drawers, despite the hardware in them usually being still perfectly fine. Reusing these little computers for another purpose once the phone’s manufacturer drops support is made hard by a range of hardware and software (driver) issues. One possible way to do so is suggested by [Doctor Volt] in a video where a Samsung Galaxy S4 is combined with a USB-connected FT232R board to add external GPIO.

The idea is pretty simple: the serial adapter is recognized by the existing Android OS and within the standard Android development environment this module can be used. Within this demonstrator it’s merely used to blink some LEDs and react to inputs, but it shows how to reuse one of these phones in a non-destructive manner. Even better is that the phone’s existing sensors and cameras can still be used as normal in this way, too, which opens a whole range of (cheap) DIY projects that can be programmed either in Java/Kotlin or in C or C++ via the Native Development Kit.

The only wrinkle is that while the phone is connected like this, charging is not possible. For the S4 it’s easy to solve as it has a removable battery, so an external power input was wired in with a dummy battery-sized bit of perfboard. With modern phones without removable batteries simultaneous USB/audio dongle and charging usage via the USB-C connector is claimed to be possible, but this is something to check beforehand.

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Rollercoasters Are Triggering The IPhone’s Crash Detection System

October 12, 2022 by Lewin Day 68 Comments

Apple has been busy adding new features to its smartphone and smartwatch offerings. Its new iPhone 14 and Apple Watch 8 now feature a safety system that contacts emergency services in the event the user is in a automobile accident.

As with so many new technologies though, the feature has fallen afoul of the law of unintended consequences. Reports are that the “crash detection system” is falsely triggering on rollercoasters and in other strange circumstances. Let’s take a look at how these systems work, and why this might be happening.

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Lego Microscope Aims To Discover Future Scientists

June 28, 2021 by Dan Maloney 7 Comments

When it comes to inspiring a lifelong appreciation of science, few experiences are as powerful as that first glimpse of the world swimming in a drop of pond water as seen through a decent microscope. But sadly, access to a microscope is hardly universal, denying that life-changing view of the world to far too many people.

There have been plenty of attempts to fix this problem before, but we’re intrigued to see Legos used to build a usable microscope, primarily for STEM outreach. It’s the subject of a scholarly paper (preprint) by [Bart E. Vos], [Emil Betz Blesa], and [Timo Betz]. The build almost exclusively uses Lego parts — pretty common ones at that — and there’s a complete list of the parts needed, which can either be sourced from online suppliers, who will kit up the parts for you, or by digging through the old Lego bin. Even the illuminator is a stock part, although you’ll likely want to replace the orange LED buried within with a white one. The only major non-Lego parts are the lenses, which can either be sourced online or, for the high-power objective, pulled from an old iPhone camera. The really slick part is the build instructions (PDF), which are formatted exactly like the manual from any Lego kit, making the build process easily accessible to anyone who has built Lego before.

As for results, they’re really not bad. Images of typical samples, like salt crystal, red onion cells, and water fleas are remarkably clear and detailed. It might no be a lab-grade Lego microscope, but it looks like it’s more than up to its intended use.

Thanks for the heads up on this, [Jef].

Smartphone Mod Goes Out On A Limb

October 6, 2018 by Lewin Day 24 Comments

The modern smartphone has a variety of ways to interact with its user – the screen, the speakers, and of course, the vibration motor. But what if your phone could interact physically? It might be unnerving, but it could also be useful – and MobiLimb explores exactly this possibility.

Yes, that’s right – it’s a finger for your mobile phone. MobiLimb has five degrees of freedom, and is built using servomotors which allow both accurate movement as well as positional feedback into the device. Additionally, a touch-sensitive potentiometer is fitted, allowing the robofinger to respond to touch inputs.

The brains behind the show are provided by an Arduino Leonardo Pro Micro, and as is usual on such projects, the mechanical assembly is 3D printed – an excellent choice for producing small, complex parts. Just imagine the difficulty of trying to produce robotic fingers with classic machine tools!

The project video shows many different possibilities for using the MobiLimb – from use as a basic notification device, to allowing the smartphone to crawl along a table. We frankly can’t wait until there’s a fully-functional scorpion chassis to drop an iPhone into – the sky really is the limit here.

Interested in other unique ways to interact with your smartphone? Check out these nifty 3D printed physical buttons.

Ask Hackaday: Why Did Modular Smart Phones Fail?

April 21, 2017 by Jack Laidlaw 96 Comments

Remember all the talk about modular smart phones? They sounded amazing! instead of upgrading your phone you would just upgrade the parts a bit like a computer but more simplistic. Well it seems modular phones are dead (video, embedded below) even after a lot of major phone manufacturers were jumping on the bandwagon. Even Google got on-board with Google Ara which was subsequently cancelled. LG released the G5 but it didn’t fare too well. The Moto Z from Motorola seemed to suffer from the same lack of interest. The buzz was there when the concept of these modular phones was announced, and people were genuinely exited about the possibilities. What went wrong?

For a start people expect their phones to have everything on board already, whether it be cameras, GPS, WiFi, high-capacity batteries or high-resolution screens. Consumers expect these things to come as standard. Why would they go out and buy a module when other phones on the market already have these things?

Sure you could get some weird and wonderful modules like extra loud speakers or perhaps a projector, but the demand for these items was small. And because these extras are already available as separate accessories not locked down to one device, it was a non starter from the beginning.

When we did our user studies. What we found is that most users don’t care about modularizing the core functions. They expect them all to be there, to always work and to be consistent. — Lead engineer Project Ara

The hackability of these phones would have been interesting to say the least, had they come to the mainstream. It just seems the public want thin sleek aluminum phones that they treat more as a status symbol than anything else. Modular phones have to be more bulky to accommodate the power/data rails and magnets for the modules, so they’ll lose out in pocketability. Still, we hope the idea is revisited in the future and not left on the scrap-heap of obsolescence.

Would you buy a modular smart phone? Even if it is bigger or more expensive? Is that really why they failed?
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Phone Scope Build Uses Old Optical Drive

September 10, 2015 by Al Williams 13 Comments

It is hardly news that you can use your smart phone as a really crummy oscilloscope. You can even use it as an audio frequency signal generator. There are also plenty of projects that allow you to buffer signals going in and out of your phone to make these apps more useful and protect your phone’s circuitry to some degree. What caught our eye with [loboat’s] phone oscilloscope project was its construction.

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Smart Phone Camera Turns Laser Cutter Into Hi-Res Scanner

September 9, 2015 by Dan Maloney 35 Comments

Getting decent macro photos always seems to be a chore. Some important detail always seems to be just outside of the depth of field, or you have to be zoomed in so close that you get great detail in one spot but miss the big picture. [Nate B] had such a problem while trying to document some PC boards, and he came up with a nifty hack that uses a laser cutter and a smart phone camera to do the job.

Having first tried scanning the boards with a flat-bed scanner but finding the depth of field unsatisfactory, [Nate B] then went on to his Samsung phone’s camera. Set to panorama mode, he manually scanned across the boards and let the camera stitch the images together. The results were better, but the wobblies got the better of him and the images showed it. He then decided to use a laser cutter — with the laser disabled, of course — as an impromptu X-Y stage to raster his camera above the boards. In a slightly cringe-worthy move, he gingerly clamped the phone to the cutter gantry, started the panorama, and let the cutter move over the board. This results in a rock-solid pictures of his boards with a lot of detail – perfect for his documentation. As a bonus, the honeycomb laser cutter bed makes for an interesting background texture.

Obviously anything could be used to raster a camera and achieve similar results, but full points here for maximizing available resources and not over-complicating a simple job. Yet another reason you can use to justify that laser-cutter purchase.

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