Hackaday Podcast Ep014: Keeping Raspberry’s SD Card Alive, We Love MRRF, And How Hot Are Flip Chips?

Elliot Williams and Mike Szczys take a look at advances in photogrammetry (building 3D models out of many photographs from a regular camera), a delay pedal that’s both aesthetically and aurally pleasing, and the power of AI to identify garden slugs. Mike interviews Scotty Allen while walking the streets and stores of the Shenzhen Electronics markets. We delve into SD card problems with Raspberry Pi, putting industrial controls on your desk, building a Geiger counter for WiFi, and the sad truth about metal 3D printing.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Give Your Raspberry Pi SD Card a Break: Log to RAM

The fragility of SD cards is the weak link in the Raspberry Pi ecosystem. Most of us seem to have at least one Pi tucked away somewhere, running a Magic Mirror, driving security cameras, or even taking care of a media library. But chances are, that Pi is writing lots and lots of log files. Logging is good — it helps when tracking down issues — but uncontrolled logging can lead to problems down the road with the Pi’s SD card.

[Erich Styger] has a neat way to avoid SD card logging issues on Raspberry Pi, he calls it a solution to reduce “thrashing” of the SD card. The problem is that flash memory segments wear out after a fairly low number of erase cycles, and the SD card’s wear-leveling algorithm will eventually cordon off enough of the card to cause file system issues. His “Log2Ram” is a simple Unix shell script that sets up a mount point for logging in RAM rather than on the SD card.

The idea is that any application or service sending log entries to /var/log will actually be writing them to virtual log files, which won’t rack up any activity on the SD card. Every hour, a cron job sweeps the virtual logs out to the SD card, greatly reducing its wear. There’s still a chance to lose logging data before it’s swept to disk, but if you have relatively stable system it’s a small price to pay for the long-term health of a Pi that’s out of sight and out of mind.

One thing we really like about [Erich]’s project is that it’s a great example of shell scripting and Linux admin concepts. If you need more information on such things, check out [Al Williams’] Linux-Fu series. It goes back quite a way, so settle in for some good binge reading.

Raspberry Pi Breathes Life into a Scale Model SEGA

Miniature game consoles are all the rage right now. Many of the big names in gaming are releasing their own official “mini” versions of their classic machines, but naturally we see plenty of DIY builds around these parts as well. Generally they’re enclosed in a 3D printed model of whatever system they’re looking to emulate, but as you might expect that involves a lot of sanding and painting to achieve a professional look.

But for SEGA Genesis (or Mega Drive as it was known outside the US) fans, there’s a new option. A company by the name of Retro Electro Models has released a high-fidelity scale model of SEGA’s classic console, so naturally somebody hacked it to hold a Raspberry Pi. Wanting to do the scale detailing of the model justice, [Andrew Armstrong] went the extra mile to get the power button on the front of the console working, and even added support for swapping games via RFID tags.

[Andrew] uses the Raspberry Pi 3 A+ which ended up being the perfect size to fit inside the model. Fitting the Pi Zero would have been even easier, but it lacks the horsepower of its bigger siblings. The RFID reader is connected to the Pi over SPI, and the reed switch used to detect when the power switch has been moved is wired directly to the GPIO pins. The system is powered by a USB cable soldered directly to Pi’s PCB and ran out a small hole in the back of the case.

For input, [Andrew] is using a small wireless keyboard that includes a touch pad and gaming controls. Unfortunately, it has a proprietary receiver which had to be integrated into the system. In a particularly nice touch, he used snipped off component leads to “wire” the receiver’s PCB directly to the pins of the Pi’s USB port. Not only does it look cool, but provides a rigid enough connection that he didn’t even need to glue it down to keep it from rattling around inside the case. Definitely a tip to keep in the back of your mind.

The software side of this project is about what you’d expect for an emulation console, though with the added trickery of loading games based on their RFID tag. At this point [Andrew] only has a single “cartridge” for the system, so he simply drops the tags into the cartridge slot of the console to load up a new title. It doesn’t look like Retro Electro Models is selling loose cartridges (which makes sense, all things considered), so there might still be a job for your 3D printer yet if you want to have a library of scale cartridges to go with your console.

For those of you who were on Team Nintendo in the 1990’s, we’ve seen a similar build done with a 3D printed case. Of course, if even these consoles are a bit too recent for your tastes, you could build a miniature Vectrex instead.

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Not All Raspberry Pi Laptops Have QWERTY Keyboards And Screens

Our recent coverage of a Raspberry Pi Zero inside the official Pi keyboard prompted a reader to point us to another far more unusual keyboard with a Pi Zero inside it. It may be a couple of years old, but [Mario Lang]’s Braille keyboard and display with built-in Pi is still an interesting project and one that should give sighted readers who have not encountered a Braille display an introduction to the technology.

The model in question is a Handy Tech Active Star 40, which seems to have been designed to have a laptop sit on top of it. A laptop was not the limit of its capabilities, because it also has a compartment with a handy USB connector that was intended to take a smartphone and thus makes a perfect receptacle for a Pi Zero. Sadly the larger boards are a little tall with their connectors.

If this hack were preformed today he would undoubtedly have used a Pi Zero W, but since the Zero he had did not possess WiFi he relied upon a Bluetooth dongle for connectivity to the outside world. The BRLTTY screen reader provides a Braille interface to the Linux console, resulting in an all-in-one Braille computer in a very compact form factor.

This is one portable Braille computer, but it’s by no means the only one we’ve seen. Thanks [Simon Kainz] for the tip, and here’s a nod to the Pi keyboard that inspired him.

Here’s The First Person To Put A Pi In The Raspberry Pi Keyboard

Last week, the Raspberry Pi foundation released the first official Raspberry Pi-branded keyboard and mouse. As a keyboard, it’s probably pretty great; it’s clad in a raspberry and white color scheme, the meta key is the Pi logo, there are function keys. Sure, the Ctrl and Caps Lock keys are in their usual, modern, incorrect positions (each day we stray further from God’s light) but there’s also a built-in USB hub. Everything balances out, I guess.

The Pi keyboard started shipping this week, and it took two days for someone to put a Pi zero inside. Here’s how you do it, and here’s how you turn a Pi keyboard into a home computer, like a speccy or C64.

The parts required for this build include the official Pi keyboard, a Pi Zero W, an Adafruit Powerboost, which is basically the circuitry inside a USB power bank, and a LiPo battery. The project starts by disassembling the keyboard with a spudger, screwdriver, or other small wedge-type tool, disconnecting the keyboard’s ribbon cables, and carefully shaving down the injection molded webbing that adds strength to the keyboard’s enclosure. The project is wrapped up by drilling holes for a power LED, a button to turn the Pi on and off, and the holes for the USB and HDMI ports.

One shortcoming of this build is the use of a male-to-male USB cable to connect the keyboard half of the circuitry to the Pi. This can be worked around by simply soldering a few pieces of magnet wire from the USB port on the Pi to the USB input on the USB hub. But hey, doing it this way gives the Official Pi keyboard a convenient carrying handle, and when one of the ports breaks you’ll be able to do it the right way the second time. Great work.

Raspberry Pi Tracks Humans, Blasts Them With Heat Rays

Given how long humans have been warming themselves up, you’d think we would have worked out all the kinks by now. But even with central heating, and indeed sometimes because of it, some places we frequent just aren’t that cozy. In such cases, it often pays to heat the person, not the room, but that can be awkward, to say the least.

Hacking polymath [Matthias Wandel] worked out a solution to his cold shop with this target-tracking infrared heater. The heater is one of those radiant deals with the parabolic dish, and as anyone who’s walked past one on demo in Costco knows, they throw a lot of heat in a very narrow beam. [Matthias] leveraged a previous project that he whipped up for offline surveillance as the core of the project. Running on a Raspberry Pi with a camera, the custom software analyzes images and locates motion across the width of a frame. That drives a stepper that swivels a platform for the heater. The video below shows the build and the successful tests; however, fans of [Matthias] should prepare themselves for a shock as he very nearly purchases a lazy susan to serve as the base for the heater rather than building one.

We’re never disappointed by [Matthias]’ videos, and we’re always impressed by his range as a hacker. From DIY power tools to wooden logic circuits to his recent Lego chocolate engraver, he always finds ways to make things interesting.

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A Raspberry Pi Terminal Fit For Fallout 76

The Fallout series of video games provide a wonderful alternative history that answers the question of what might have happened had the microchip never been invented. Yes, most things run on tubes, and apparently you can implement an AI that passes a Turing test in tubes (does the Turing test apply if you’re comparing it against NPCs?). Of course, as with all of computer history, the coolest parts of Fallout are the computer terminals, so [LowBudgetTech] decided to build one. All the files are available, and if you have a Pi sitting around this is a good weekend project.

This terminal has a host of features that are well-suited for the modern vault dweller. Of note, the entire case is 3D printed, in multiple pieces. Sure, considering the display is an LCD it’s a tiny bit thick, but you don’t get the Atomic age aesthetic without a big CRT, do you? The keyboard is a standard, off-the-shelf mechanical keyboard for clicky goodness with vintage-style keycaps. There’s a 3.5″ USB floppy drive, because there’s nothing that will survive a nuclear holocaust like magnetic media. The rest of the build is a Raspberry Pi 3B+, which is more than enough compute power to open a door shaped like a gear.

As for what you would do with a retro-inspired Pi terminal, well, it would make a good computer for the workbench, and since the case is already designed for a 3.5″ drive, you could use this to archive some old media. If there’s one thing the apocalypse tells us, it’s that these old terminals will still be kicking after a few hundred years.