Powering A Cellphone With Gasoline

September 1, 2022 by Lewin Day 24 Comments

Batteries are a really useful way to store energy, but their energy density in regards to both weight and volume is disappointing. In these regards, they really can’t compete with fossil fuels. Thus, [bryan.lowder] decided to see if he could charge a phone with fossil fuels as safely and inoffensively as possible.

Obviously, with many national grids relying on fossil fuels for a large part of their generation, most of us are already charging our phones with fossil fuels to some degree. However, the aim here was to do so more directly, without incurring transmission losses from the long runs through the power grid. Continue reading “Powering A Cellphone With Gasoline” →

Turning The Back Of Your Phone Into A Touchpad

July 21, 2022 by Lewin Day 28 Comments

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.

Touches on the 2D rear matrix are translated into a pair of touches on the linear line of pads on the front screen. This can then be reconstructed into the touch location on the rear touchpad.

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. Continue reading “Turning The Back Of Your Phone Into A Touchpad” →

Porting DOOM But In The Opposite Direction

July 20, 2022 by Lewin Day 4 Comments

DOOM was first released for MS-DOS, and is one of the pillar titles of the broader first-person-shooter genre. It’s also become a bit of a meme for being ported to any and every weird platform under the sun. Now, a group of developers in Costa Rica have found a way to flip that joke around – by porting an old mobile DOOM game back to the PC.

The game in question is DOOM RPG, made for BREW and Java-compatible phones in 2005. A group named GEC.inc has taken that game and ported it to Windows, outlining their work on the Doomworld forums. As with many such projects, the port is freely available, but doesn’t include the raw game files themselves due to copyright. You’ll have to find the gamedata yourself, and combine it with the files the group published on the forum to get it to work on a modern PC.

For those that have missed the turn-based role playing game based in the DOOM universe (Doomiverse?), today is a good day. No longer must you pine for your ancient, crusty Java smartphone of yesteryear. Now you can play the game on a less awful platform, and listen to the unique and compelling MIDI-esque soundtrack.

Doom ports are hot right now, whether it’s to forgotten Apple OSes or Sega arcade hardware. Video after the break.

Continue reading “Porting DOOM But In The Opposite Direction” →

Lenses: From Fire Starters To Smart Phones And VR

June 28, 2022 by Matthew Carlson 21 Comments

In antiquity, we see examples of magnifying crystals formed into a biconvex shape as early as the 7th century BC. Whether the people of that period used them either for fire-starting purposes or vision is unclear. Still, it is famously said that Emperor Nero of Rome watched gladiator games through an emerald.

Needless to say, the views we get through modern lenses are a lot more realistic. So how did we get from simple magnifying systems to the complex lens systems we see today? We start with a quick journey through the history of the camera and the lens, and we’ll end up with the cutting edge in lens design for smartphone cameras and VR headsets.

Continue reading “Lenses: From Fire Starters To Smart Phones And VR” →

Metal Detector Gets Help From Smartphone

June 27, 2022 by Bryan Cockfield 15 Comments

[mircemk] is quite a wizard when it comes to using coils of wires in projects, especially when their application is within easy-to-build metal detectors. There are all kinds of ways to send signals through coiled wire to detect metal objects in the ground, and today [mircemk] is demonstrating a new method he is experimenting with which uses a smartphone to detect the frequency changes generated by the metal detector.

Like other metal detectors, this one uses two coils of wire with an oscillator circuit and some transistors. The unique part of this build, though, is how the detector alerts the user to a piece of metal. Normally there would be an audible alert as the frequencies of the circuit change when in the presence of metal, but this one uses a smartphone to analyze the frequency information instead. The circuit is fed directly into the headphone jack on the smartphone and can be calibrated and used from within an Android app.

Not only can this build detect metal, but it can discriminate between different types of metal. [mircemk] notes that since this was just for experimentation, it needs to be calibrated often and isn’t as sensitive as others he’s built in the past. Of course this build also presumes that your phone still has a headphone jack, but we won’t dig up that can of worms for this feature. Instead, we’ll point out that [mircemk] has shown off other builds that don’t require any external hardware to uncover buried treasure.

Continue reading “Metal Detector Gets Help From Smartphone” →

Two Nokia 1860 phones side by side - a Notkia-modded phone on the right, and an unmodified Nokia phone on the left

Notkia: Building An Open And Linux-Powered Numpad Phone

June 18, 2022 by Arya Voronova 42 Comments

Many of us hackers have a longing for numpad-adorned mobile phones. We also have a shared understanding that, nowadays, such a phone has to be open and Linux-powered. Today’s project, Notkia, is the most promising and realistic effort at building a keypad phone that fits our requirements. Notkia is a replacement board for Nokia 168x series phones, equipped with an improved display, USB-C, WiFi, Bluetooth, and LoRa — and [Reimu NotMoe] of [SudoMaker] tells us this project’s extensive story.

The Notkia effort started over two years ago, because of [Reimu]’s increasing dislike for modern smartphones — something every hacker is familiar with. Her first-hand experience with privacy violations and hackability limitations on Android phones is recounted in detail, leading to a strong belief that there are fundamental problems with phones available nowadays. Building new hardware from the ground up seems to be the way forward. Two years later, this is exactly what we got!

Continue reading “Notkia: Building An Open And Linux-Powered Numpad Phone” →

How A Smartphone Is Made, In Eight “Easy” Blocks

May 9, 2022 by Matthew Carlson 21 Comments

The smartphone represents one of the most significant shifts in our world. In less than thirteen years, we went from some people owning a dumb phone to the majority of the planet having a smartphone (~83.7% as of 2022, according to Statista). There are very few things that a larger percentage of people on this planet have. Not clean water, not housing, not even food.

How does a smartphone work? Most people have no idea; they are insanely complicated devices. However, you can break them down into eight submodules, each of which is merely complex. What makes them work is that each of these components can be made small, at massive economies of scale, and are tightly integrated, allowing easy assembly.

So without further ado, the fundamental eight building blocks of the modern cellphone are: the application processor, the baseband processor, a SIM card, the RF processor, sensors, a display, cameras & lenses, and power management. Let’s have a look at them all, and how they fit together.

Continue reading “How A Smartphone Is Made, In Eight “Easy” Blocks” →