The Mini Console Revolution, And Why Hackers Passed Them By

August 27, 2020 by Zoe Skyforest 31 Comments

The Raspberry Pi was initially developed as an educational tool. With its bargain price and digital IO, it quickly became a hacker favorite. It also packed just enough power to serve as a compact emulation platform for anyone savvy enough to load up a few ROMs on an SD card.

Video game titans haven’t turned a blind eye to this, realising there’s still a market for classic titles. Combine that with the Internet’s love of anything small and cute, and the market was primed for the release of tiny retro consoles.

Often selling out quickly upon release, the devices have met with a mixed reception at times due to the quality of the experience and the games included in the box. With so many people turning the Pi into a retrogaming machine, these mini-consoles purpose built for the same should have been immediately loved by hardware hackers, right? So what happened?

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Tiny Robot Beetle Runs On Alcohol

August 26, 2020 by Zoe Skyforest 44 Comments

Batteries have come a long way in the past few centuries, but pale in comparison to hydrocarbon fuels when it comes to energy density. When it comes to packing plenty of juice in a light, compact package, hydrocarbons are the way to go. Recently, researchers have begun to take advantage of this, powering small robots with liquid fuels. Just like Bending Unit 22, aka Bender Bending Rodriguez, this tiny robotic beetle runs on alcohol.

Robeetle can carry up to 2.6 times its own weight, using Nitinol muscle wires to move its legs.

Affectionately named Robeetle, the tiny ‘bot weighs just 88 milligrams, comparable in mass its insectoid contemporaries. It stores methanol in a polyimide film tank, operating for up to 2 hours on a single fill. As shown in the video, a solely mechanical control system is used to actuate the robot’s legs. In the neutral state, vents in the fuel tank are open, releasing methanol vapor. This passes over nitinol muscle wires coated in a special catalyst which causes the combustion of the methanol, heating the wires. The wires then contract, moving the legs, and closing the vents. When the wire cools, the wires relax, opening the vents and beginning the cycle anew.

While the ‘bot is solely capable of walking in a single direction, it nevertheless shows the possibilities enabled by powering small devices from energy-dense fuels. Waiting for improved battery technologies to develop is such a bore, after all. We look forward to swarms of such ‘bots exploring disaster areas or performing environmental sampling in years to come. The scientific paper outlines the research outcomes in detail.

We love tiny robots at Hackaday; we’ve featured a few in the past, too. Video after the break.

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Driving A PAL TV Over RF Thanks To PWM Harmonics

August 26, 2020 by Zoe Skyforest 11 Comments

While most analog televisions come with composite video inputs on a yellow RCA jack, the feature is not universal. This problem was even more prevalent in the 1980s, and most home consoles got around the problem by instead feeding video to the television’s tuner with an RF modulator. [Manzel Seet] had just such a television which used the PAL standard. Wanting to display images from a microcontroller, he put together PAL-Streamer.

The aim of the project was to display images on an analog television with minimal investment in hardware over and above what [Manzel] already had on hand. To this end, the project was built using a STM32F411 Nucleo development board. Capable of running at clock speeds up to 100 MHz, there’s plenty of grunt to handle demanding tasks like outputting video signals to a TV.

To achieve the target frequency of VHF Channel 3 (61.25 MHz), [Manzel] elected to rely on the onboard PWM hardware, after being inspired by [CNLohr]’s ATTiny NTSC project. The project takes advantage of the odd harmonics of square waves. Setting the PWM output to operate at 6.86 MHz, the ninth harmonic ends up at around 61.71 MHz, close enough to be tuned in on the TV set. With the hard part done, [Manzel] then implemented a virtual COM port allowing an attached PC to send PNG images or GIF animations to the display.

It’s a fun project that shows it’s possible to drive all kinds of analog displays if you’re willing to be creative about how you do it. Files are available on GitHub for those eager to recreate the work. [Manzel] points out that this method does put out a lot of RF energy in the surrounding bands, but for direct hookup to an antenna input, it works just fine. We love to see creative video projects on microcontrollers, so if you’ve figured out how to get an Arduino Uno to do 1080P over HDMI, be sure to let us know. Video after the break.

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You’ve Never Seen This RetroPie Emulator Console: Watermelon

August 26, 2020 by Zoe Skyforest 5 Comments

The Raspberry Pi is a hugely popular platform for emulating older consoles, with the RetroPie framework making it easy to get started in no time at all. Often, these single board computers get built into fun arcade boxes or replica console shells to add to the charm. That’s all been done, so instead, [Cedishappy] decided to go in his own direction – resulting in the wonderful Watermelon Gameboy.

What sounds like a trivial exercise of building a RetroPie rig in a unique enclosure actually comes with some engineering challenges. The basics are all pretty standard – GPIO pins interfacing buttons, a speaker and the screen, emulating a Gameboy Advance. But the mechanical implementation is more complex. The watermelon is first cut open, having its red flesh removed, leaving just the rind. Paper and cardboard templates are then used to make holes for the buttons and screen. Unfortunately, hot glue doesn’t work on watermelon, so instead, toothpicks were used to hold the screen and speaker in place. To protect the electronics from the moist melony environment inside, clear food wrap was applied to the Raspberry Pi and other components where needed.

[Cedishappy] goes above and beyond with the project video charmingly showing the reactions of bystanders to the contextually confusing game system. The combination of electronics with fruit and vegetables is an area we don’t see explored often enough; our own [Mike Szczys] built a magnificent LED Jack-o-Lantern that really looks the business. Video after the break.

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New Arduino JPEG Library Focuses On Speed

August 26, 2020 by Zoe Skyforest 10 Comments

Working with graphics on microcontrollers has always meant focusing on making the most of limited resources. Particularly in the 8-bit era, all manner of tricks were used to get low-performance chips to achieve feats beyond their lowly station. However, these days, we’re blessed with 32-bit workhorses with clock speeds in the tens, or even hundreds, of MHz and many kilobytes of RAM to match. It’s these higher performance chips [Larry] had in mind when writing his JPEGDEC library.

As [Larry] discusses in a blog post on the topic, JPEG libraries already exist for the Arduino platform. However, many of these are aimed at 8-bit platforms with tiny amounts of RAM. While it’s possible to decode JPEGs piece by piece with some intelligent code under these conditions, it’s possible to go much faster when you’ve got a little more headroom. [Larry] does a great job of explaining the variety of optimizations he’s developed in the two decades since writing his first JPEG decoder back in 1994. From eliminating unnecessary marker checks to ignoring unneeded data for scaled-down output, it all adds up to get the job done faster. The library targets the Cortex-M0+, or any chip with a minimum of 20K of RAM, as its bare minimum to operate. Faster chips with higher clock rates naturally do better, and [Larry] provides benchmark decoding times for various common hardware using the library.

We’ve featured [Larry]’s GIF decoder for the Arduino platform before, again a useful library that’s optimised for good performance. If you’ve got your own neat tricks for image processing on microcontrollers, you know how to call!

The USB Null Modem Cable Is Now A Thing

August 25, 2020 by Zoe Skyforest 87 Comments

The classic serial null-modem cable was, among other things, used to connect two computers together for communications and file transfer. Largely eliminated in daily use by the advent of home networking, there are still fringe applications where such a thing can come in handy. [Nick Sayer] needed just such a tool, but one that would work in a modern USB environment. Enter the isolated USB null-modem.

The device consists of two USB Communication Device Class, or CDC chips, creating a USB serial port for each attached computer. The TX and RX lines are cross-connected to allow communication between the two sides. Rather than directly connect the lines, however, they pass through an opto-isolator. This is important, as it allows two computers at different ground potentials to be safely connected to each other without damage.

[Nick] originally created the device to solve a specific problem at his day job, but community response was large enough that he was kind enough to share the project online. Expect to see devices available on Tindie in future for those that need a hookup. While it’s not something everyone will need, for those that do, it should come in handy. If you’re looking for other useful applications for USB-serial devices, there’s plenty – you can even try your hand at software-defined radio!

Reactive Pixel Lamps Create Colourful Vibes On Command

August 24, 2020 by Zoe Skyforest 3 Comments

Phillips Ambilight technology is a curious thing, never quite catching on in the mainstream due to its proprietary nature. Consisting of an LED array that sits behind a television screen, it projects colours relevant to the content on screen to create a greater feeling of ambience. [Ed Chamberlain]’s reactive pixel lamps aim to do much the same thing in a more distributed way.

Each pixel lamp consists of a Wemos D1 controller fitted with an old-school 4-wire RGB LED. The components are placed in a 3D printed translucent cube, which serves as an attractive enclosure and diffuser. With WiFi connectivity on board, it’s possible to connect the individual cubes up to a Raspberry Pi serving as a Phillips Hue bridge thanks to DIYHue. Once setup, the lights can be configured as an Ambilight system within the Phillips Hue app.

It’s an impressive way to give a room reactive lighting on a budget, without resorting to costly off-the-shelf solutions. We’d love to see this expanded further, as we’re sure a room full of reactive lights would be truly a sight to behold. Other methods to recreate the Ambilight technology are possible, too. Video after the break.

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