The Tiniest RetroPie

The RetroPie project is a software suite for the Raspberry Pi that allows the user to easily play classic video games through emulators. It’s been around for a while now, so it’s relatively trivial to get this set up with a basic controller and video output. That means that the race is on for novel ways of implementing a RetroPie, which [Christian] has taken as a sort of challenge, building the tiniest RetroPie he possibly could.

The constraints he set for himself were to get the project in at under 100 mm. For that he used a Pi Zero loaded with the RetroPie software and paired it with a 1.44″ screen. There’s a tiny LiPo battery hidden in there, as well as a small audio amplifier. Almost everything else is 3D printed including the case, the D-pad, and the buttons. The entire build is available on Thingiverse as well if you’d like to roll out your own.

While this might be the smallest RetroPie we’ve seen, there are still some honorable mentions. There’s one other handheld we’ve seen with more modest dimensions, and another one was crammed into an Altoids tin with a clamshell screen. It’s an exciting time to be alive!

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A Practical Portable Wii Emerges from the Memes

A few months ago, [Shank] built what will almost certainly go down in history as the world’s smallest portable Nintendo Wii. As it turns out, the Wii motherboard is home to a lot of unnecessary hardware, and with a careful hand and an eye for detail, it’s possible to physically cut it down to a much smaller unit; allowing this particularly tenacious hacker to put an actual Wii, along with everything else required to make it portable, into an Altoids tin.

As you might expect, between the cramped controls, comically short battery life, and the fact that the whole thing got hot to the touch during use, it was a miserable excuse for a portable console. But the incredible response the project received inspired [Shank] to dust off an earlier project: a far more practical portable Wii that he calls PiiWii. This time around the handheld is a more reasonable size, a useful battery life, and proper controls. It even has an integrated “Sensor Bar” so you can use real Wii Remotes with it. It might not be the prettiest portable console conversion we’ve ever seen, but it certainly ranks up there as one of the most complete.

[Shank] actually “finished” the PiiWii some time ago, but in his rush to complete the project he got a little overzealous with the hot glue and ended up with a device that was difficult to diagnose and fix when things started to go wrong. He shelved the project and moved on to his Altoids tin build, which helped him refine his Wii shrinking skills. With a clearer head and some more practical experience under his belt, the PiiWii was revamped and is clearly all the better for it.

Unlike previous Wii portables we’ve seen, there’s no attempt at adding GameCube controller ports or video out capability. It’s built to be a purely handheld system, and that focus has delivered a system that’s roughly the size of the original Game Boy Advance. Beyond the cleverly sliced Wii motherboard, the inside of the PiiWii features a 3.5 inch display, a custom designed audio amplifier PCB, four 3400 mAh cells which deliver a run time of around four hours, a 3DS “slider” analog stick, and a generous helping of Kapton tape in place of hot glue.

If there’s any criticism of the PiiWii, it’s likely going to be about the system’s boxy exterior. But as [Shank] explains, there’s an excellent reason for that: it’s literally built into a project box. He simply took a commercially available ABS project box, the Polycase SL 57, and made all his openings on the front with a laser cutter. Other than the fact taking a laser to ABS releases hydrogen cyanide, he found it a good way to quickly knock out a custom enclosure.

Last year we took a look his ridiculously small Altoids tin Wii, and while that was an impressive project to be sure, we’re glad he revisited the PiiWii and showed that a portable Wii can be more than just a novelty. Compared to other systems, the Wii doesn’t seem to get the portable treatment that often, so we’re always glad to see somebody come in and do the concept justice.

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Get Your Tweets Without Looking

Head-mounted displays range from cumbersome to glass-hole-ish. Smart watches have their niche, but they still take your eyes away from whatever you are doing, like driving. Voice assistants can read to you, but they require a speaker that everyone else in the car has to listen to, or a headset that blocks out important sound. Ignoring incoming messages is out of the question so the answer may be to use a different sense than vision. A joint project between Facebook Inc. and the Massachusetts Institute of Technology have a solution which uses the somatosensory reception of your forearm.

A similar idea came across our desk years ago and seemed promising, but it is hard to sell something that is more difficult than the current technique, even if it is advantageous in the long run. In 2013, a wearer had his or her back covered in vibrator motors, and it acted like the haptic version of a spectrum analyzer. Now, the vibrators have been reduced in number to fit under a sleeve by utilizing patterns. It is being developed for people with hearing or vision impairment but what drivers aren’t impaired while looking at their phones?

Patterns are what really set this version apart. Rather than relaying a discrete note on a finger, or a range of values across the back, the 39 English phenomes are given a unique sequence of vibrations which is enough to encode any word. A phenome phoneme is the smallest distinct unit of speech. The video below shows how those phonemes are translated to haptic feedback. Hopefully, we can send tweets without using our hands or mouths to upgrade to complete telepathy.

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Building Portable Linux Devices: Never Been Easier, But Still Hard

We live in a Golden Age of single-board computers. There was a time when a portable computer that was any good was a relatively rare and expensive device, certainly not something you could expect to replicate for yourself. A Psion, or later a Palm or perhaps a WinCE device would have been a lot more than an impulse purchase, and could not easily have been replicated using the components then available to the experimenter.

Thanks to spin-offs from technology developed for set-top boxes and mobile phones we can now buy any one of a pile of different boards that have almost equivalent power to a desktop computer. The experimenter can leverage that computing power to create their own small portables. Zerophone creator Arsenijs Picugins spoke about the tricky parts of designing a LInux portable at the recent Hackaday Superconference. You’ll find his talk below the break, which makes for a fascinating primer for those tempted to walk in his footsteps.

Zerophone – a Raspberry Pi Smartphone

Minor Details of Portables are the Majority of the Build

In theory, it’s pretty easy to use one of these boards to make a portable computer. Take one of the smaller members of the Raspberry Pi or Beaglebone families, add a battery and a display, and away you go. But as always the devil is in the detail, and for a truly successful build there are a wealth of variables to attend to.

In his talk, Arsenijs takes us through the challenges of power supplies, connectors, and interfaces. In particular there is considerable challenge to running an SBC from a battery small enough to be portable, as efficiency concerns and the ability to easily recharge make for a critical set of choices. Then we learn of another pitfall, that of using USB as a default interface. Power loss in converting 5V to 3.3V that is inconsequential for a desktop computer is a battery-killer in a small device, so we’re pointed at the array of alternatives.

Zerophone screen menu [via @ZeroPhoneOSHW]

Screen Size is a Tricky Spec to Settle

If you’ve been tempted by one of those cheap Raspberry Pi touch screens, you’ll certainly understand that while a full desktop on a screen the size of a playing card looks cool, the reality is almost unusable. Your device will require a user interface that fits its form factor, which from his experience, Arsenijs suggests is best achieved through the medium of buttons rather than a touchscreen on smaller screens. There are a variety of UI and display libraries he introduces us to which make the whole process significantly easier.

Arsenijs’ Zerophone Raspberry Pi smartphone was a finalist in the 2017 Hackaday Prize, and remains an exemplary portable project from which many others can gain inspiration. We are privileged that he was able to bring his experience to speak at the Superconference, and his talk makes for a fascinating watch.

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Teardown of a (Relatively) Cheap Thermal Camera

The cost of tools and test equipment has largely been on the downward trend for years, making it now more affordable than ever to get into the hacking and making scene. This is particularly visible with something like the venerable oscilloscope: a piece of equipment that was near unobtainium for the home hacker a decade ago, you can now get digital pocket scope for as little as $20 USD. But there are still pieces of gear which haven’t quite hit the sort of prices we’d like to see.

A perfect example are thermal imaging cameras. The cheap ones are usually so low resolution they might as well just be thermometers, but the higher resolution ones can cost thousands. [Rob Scott] recently wrote in to tell us about a very promising middle ground, the HTI HT-A1. But he didn’t just point it out to us, he also tore it down and laid its internal’s bare for our entertainment. Now that’s our kind of introduction.

[Rob] walks us through the disassembly of the device, which is made unnecessarily difficult due to the fact that half the screws are hidden under a glued on screen bezel. That means a heat gun, a thin tool, and patience are in order if you want to get inside the device. It’s bad enough they use these kinds of construction techniques on modern smartphones, but at least they’re so thin that we can understand the reasoning. Why this chunky thing needs to resort to such measures is beyond us.

Eventually he cracks the HT-A1 open and is greeted with a single double-sided PCB. The top side is pretty much bare except for the buttons and the LCD display, and the flip side is largely just a breakout for a quad-core Allwinner A33 daughterboard. [Rob] theorizes this is to keep costs down by allowing reuse of the modular A33 board on other devices. Given the A33’s use in so many cheap tablets, it’s also possible HTI simply purchased these daughterboards as a drop-in component and designed their own board around it.

There’s not much else inside the HT-A1 beyond the rechargeable battery pack and thermal camera, both attached to the device’s rear panel. [Rob] noticed that the date on the thermal camera PCB is a full two years older than the date on the main PCB, leading one to wonder if HTI might have gotten a good deal on a bunch of these slightly outdated sensors and spun up a whole device around them.

The HT-A1 is high enough resolution that you can actually pick out individual components on a PCB, and at $400 USD is approaching a reasonable price point for the individual hacker. Which is not to say it’s cheap, but at least you get a useful tool for your money. We wouldn’t suggest you buy this device on a whim, but if you do a lot of diagnostic work, it might pay for itself after a couple repairs.

If that’s still a little too rich for your blood, we’ve covered a handful of DIY options which might better fit your budget.

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SMART Response XE Gets Wireless Bootloader

A few months back we first brought word of the progress being made in unlocking the SMART Response XE, an ATmega128RFA powered handheld computer that allowed teachers to create an interactive curriculum in the days before all the kids got Chromebooks. Featuring 2.4 Ghz wireless communication, a 384×160 LCD, and a full QWERTY keyboard, schools paid around $100 each for them 2010. Now selling for as little as $5 on eBay, these Arduino-compatible devices only need a little coaxing and an external programmer to get your own code running.

The previous post inspired [Larry Bank] to try his hand at hacking the SMART Response XE, and so far he’s made some very impressive progress. Not only has he come up with his own support library, but he’s also created a way to upload Arduino code to the devices through their integrated 802.15.4 radio. With his setup, you no longer need to open the SMART Response XE and attach a programmer, making it much easier to test and deploy software.

[Larry] has written up a very detailed account of his development process, and goes through the trouble of including his ideas that didn’t work. Getting reliable communication between two of these classroom gadgets proved a bit tricky, and it took a bit of circling around until he hit on a protocol that worked.

The trick is that you need to use one SMART Response XE attached to your computer as a “hub” to upload code to other XEs. But given how cheap they are this isn’t that big of a deal, especially considering the boost in productivity it will net you. [Larry] added a 5 x 2 female header to his “hub” XE so he could close the device back up, and also added a physical power switch. In the video after the break, you can see a demonstration of the setup sending a simple program to a nearby XE.

Between this wireless bootloader and the Arduboy compatibility covered previously, we’d suggest you get your SMART Response XE now. We wouldn’t be surprised if the prices of these things start going up like they did with the IM-ME. Continue reading “SMART Response XE Gets Wireless Bootloader”

DIY Scientific Calculator Powered By Pi Zero

It’s the eternal question hackers face: do you built it, or do you buy it? The low cost and high availability of electronic gadgets means we increasingly take the latter option. Especially since it often ends up that building your own version will cost more than just buying a commercial product; and that’s before you factor in the time you’ll spend working on it.

But such concerns clearly don’t phase [Andrea Cavalli]. Sure he could just buy a scientific calculator, but it wouldn’t really be his scientific calculator. Instead, he’s taking the scenic route and building his own scientific calculator from scratch. The case is 3D printed, the PCB is custom, and even the software is his own creation.

His PCB hooks right up to the GPIO pins of the internal Raspberry Pi Zero, making interfacing with the dome switch keyboard very easy. The board also holds the power management hardware for the device, including the physical power switch, USB connection for charging, and TPS79942DDCR linear regulator.

The case, including the buttons, is entirely 3D printed. At this point the buttons don’t actually have any labels on them, which presumably makes the calculator more than a little challenging to use, but no doubt [Andrea] is working on that for a later revision of the hardware. A particularly nice detail is the hatch to access the Pi’s micro SD card, making it easy to update the software or completely switch operating systems without having to take the calculator apart.

After the kernel messages scroll by, the Pi boots right into the Java calculator environment. This gives the user a fairly standard scientific calculator experience, complete with nice touches like variable highlighting. The Mario mini-game probably isn’t strictly required, but if you’re writing the code for your own calculator you can do whatever you want.

Here at Hackaday we’ve seen a calculator that got a Raspberry Pi upgrade, a classic scientific calculator emulated with an Arduino, and of course we’ve raved about the NumWorks open source graphing calculator. Even with such stiff competition, we think this project is well on its way to being one of the most impressive calculators we’ve ever come across.

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