It’s Doom, This Time On A Bluetooth LE Dongle

November 20, 2021 by 4 Comments

By now most readers should be used to the phenomenon of taking almost any microcontroller and coaxing it to run a port of the 1990s grand-daddy of all first-person shooters, id Software’s Doom. It’s been done on a wide array of devices, sometimes only having enough power for a demo mode but more often able to offer the full experience. Latest to the slipgate in this festival of pixelated gore is [Nicola Wrachien], who’s achieved the feat using an nRF52840-based USB Bluetooth LE dongle.

Full details can be found on his website, where the process of initial development using an Adafruit CLUE board is detailed. A 16MB FLASH chip is used for WAD storage, and an SPI colour display takes us straight to that cursed base on Phobos. The target board lacks enough I/O brought out for connection to screen and FLASH, so some trickery with 7400 logic is required to free up enough for the task. Controls are implemented via a wireless gamepad using an nRFS1822 board, complete with streamed audio to a PWM output.

The result can be seen in the video below the break, which shows a very playable game of both Doom and Doom 2 that would not have disgraced many machines of the era. This was prototyped on an Adafruit Clue board, and that could be the handheld console you’ve been looking for!

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iPodRPi by production

IPod Mod Puts Pi Zero In New Bod

November 20, 2021 by 7 Comments

We sure love to see nicely designed products get a new lease on life. Just as the new Raspberry Pi Zero 2 was being announced, [production] was stuffing an original RPi Zero into an old iPod’s case.

[production] cites several previous, similar projects that showed how to interface with the click-wheel, a perfectly fitting color display from Waveshare, and open-source software called Rockbox to run on the pi. We all stand on the shoulders of giants.

iPodRPi by production interior wiring

Some nice innovations to look for are the Pi Zero’s micro-SD card and a micro-USB charging port aligned to the large slot left from the iPod’s original 40 pin connector. Having access for charging and reflashing the card without opening the case seems quite handy. There’s a nice sized battery too, though we wonder if a smaller battery and a Qi charger could fit in the same space. Check the project’s Hackaday.io for the parts list, and GitHub for the software side of things, and all the reference links you’ll need to build your own. It looks like [production] has plans to turn old iPods into Gameboy clones, you may want to check back for progress on that.

If you just want to rock like it’s 2004, there are options to just upgrade the battery and capacity but keep your vintage iPod too.

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PinePhone Speed Up Takes Soldering

November 19, 2021 by 19 Comments

It is no secret that we like a good hack and [Federico Amedeo Izzo] explains a hack for the PinePhone that can double the speed used for the device’s memory chips. Like many good hacks, it all started with a question. [Federico] was reading a review of the PinePhone Pro (the source of the image for this post) and apparently, the eMMC memory in that phone clocks in at about 150 MB/s. The original phone gets about 50-80 MB/s.

Reading some datasheets, it looked like the same chips are in both phones and should support not only DDR52 mode — the mode the original phone uses — but also HS200 and HS400 modes which top out at 200 and 400 MB/s, respectively. But there was one problem.

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Arduino + Ham Radio = Texting

November 19, 2021 by 12 Comments

Over on the Spectrum web site, [Dale] — a relatively new ham radio operator — talks about his system for sending text messaging over VHF radios called HamMessenger. Of course, hams send messages all the time using a variety of protocols, but [Dale] wanted a self-contained and portable unit with a keyboard, screen, and a GPS receiver. So he built one. You can find his work on GitHub.

At the heart of the project is MicroAPRS, an Arduino firmware for packet radio. Instead of using a bigger computer, he decided to dedicate another Arduino to do everything but the modem function.

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Run UNIX On Microcontrollers With PDP-11 Emulator

November 19, 2021 by 40 Comments

C and C++ are powerful tools, but not everyone has the patience (or enough semicolons) to use them all the time. For a lot of us, the preference is for something a little higher level than C. While Python is arguably more straightforward, sometimes the best choice is to work within a full-fledged operating system, even if it’s on a microcontroller. For that [Chloe Lunn] decided to port Unix to several popular microcontrollers.

This is an implementation of the PDP-11 minicomputer running a Unix-based operating system as  an emulator. The PDP-11 was a popular minicomputer platform from the ’70s until the early 90s, which influenced a lot of computer and operating system designs in its time. [Chloe]’s emulator runs on the SAMD51, SAMD21, Teensy 4.1, and any Arduino Mega and is also easily portable to any other microcontrollers. Right now it is able to boot and run Unix but is currently missing support for some interfaces and other hardware.

[Chloe] reports that performance on some of the less-capable microcontrollers is not great, but that it does run perfectly on the Teensy and the SAMD51. This isn’t the first time that someone has felt the need to port Unix to something small; we featured a build before which uses the same PDP-11 implementation on a 32-bit STM32 microcontroller.

An electric mini rat rod made from mostly recycled parts.

Electric Mini Rat Rod Starts ‘Em Young

November 19, 2021 by 4 Comments

These days, a lot of people barely even say hello to their neighbors. But not [dewey302]. They’re so tight with the people next door that they built this bad-ass electric mini rat rod for the neighbors’ five-year-old kid. Talk about community!

Nearly every bit of this rod is recycled — the body is a wheelbarrow, the transaxle is from a mobility scooter, and the frame was welded together from scrap tubing including the wheelbarrow itself, and old bike or two, and some broken lawn chairs. The rear wheels are also from the ‘barrow, though the front ones were purchased (one of few new parts. Power comes from a pair of 18 V tool batteries wired in series and running through the Curtis controller from the scooter. Depending on the weight of the driver, this baby will do 10-12 MPH.

We love the look of this little rat rod, and wish we were [dewey302]’s neighbor. When you’re done poring over the pile of build pictures, be sure to watch [dewey302] and [The Kid] tear up the cul-de-sac in the video after the break.

You may have noticed the mailbox grille. Surprisingly, this is not the first mail-themed rat rod we’ve covered. Here’s one that really delivers.

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The Silent Dripper Dispenses Water Without Making Any Sound

November 19, 2021 by 6 Comments

Engineering is all about making a design that conforms to a set of requirements. Usually those are boring things like cost, power consumption, volume, mass or compatibility with existing systems. But sometimes, you have to design something with restrictions you might have never considered. [Devon Bray] was tasked with designing a system that could dispense single drops of water, while making absolutely no noise. [Devon]’s blog describes in detail the process of making The Silent Dripper, which was needed for an art installation called The Tender Interval by [Sara Dittrich].

The design process started with picking a proper pump. Centrifugal pumps can be very quiet due to their smooth, continuous motion, but are not suitable for moving small quantities of liquid. Peristaltic pumps on the other hand can generate single drops of liquid very accurately, but their gripping-and-squeezing motion creates far more sound. [Devon] still went for the latter type, and eventually discovered that filling up the pumping mechanism with lithium grease made it quiet enough for his purpose.

The pump was then mounted on a 3D-printed bracket that also contained the water feeding tube and electrical connections to the outside world. The tubing was fastened with zip ties to stop it from moving when the pump was running, and the pump itself was isolated from the bracket with rubber dampening mounts.

Another trick to silence the pump was the motor driver circuit: standard PWM drivers often cause audible whine from the motor coils because of their abrupt switching, so [Devon] went for a Trinamic SilentStepStick that regulates the current much more smoothly. The end result is a water dripper that makes less noise than a piece of tissue paper being crumpled, as you can observe in the video (embedded below) which also demonstrates the complete art installation.

We really like the mechanical design of the Dripper; as far as we’re concerned it would merit a spot in a gallery on its own. It would not be the first water dripping art project either; we’ve already seen a sculpture that apparently suspends droplets in mid-air. Continue reading “The Silent Dripper Dispenses Water Without Making Any Sound” →