A black motion system with two stepper motors. A green circuit board is fixed in a rotating cage in the center, and the entire assembly is on a white base atop a green cutting mat. Wires wind through the assembly.

Pi-lomar Puts An Observatory In Your Hands

Humans have loved looking up at the night sky for time immemorial, and that hasn’t stopped today. [MattHh] has taken this love to the next level with the Pi-lomar Miniature Observatory.

Built with a Raspberry Pi 4, a RPi Hi Quality camera, and a Pimoroni Tiny2040, this tiny observatory does a solid job of letting you observe the night sky from the comfort of your sofa (some assembly required). The current version of Pi-lomar uses a 16mm ‘telephoto’ lens and the built-in camera libraries from Raspbian Buster. This gives a field of view of approximately 21 degrees of the sky.

While small for an observatory, there are still 4 spools of 3D printing filament in the five different assemblies: the Foundation, the Platform, the Tower, the Gearboxes and the Dome. Two NEMA 17 motors are directed by the Tiny2040 to keep the motion smoother than if the RPi 4 was running them directly. The observatory isn’t waterproof, so if you make your own, don’t leave it out in the rain.

If you’re curious how we might combat the growing spectre of light pollution to better our nighttime observations, check out how blinking can help. And if you want to build a (much) larger telescope, how about using the Sun as a gravitational lens?

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Mini DDR Cabinet Gets Maximum Upgrade

Those shrunken-down arcade cabinets are a nifty idea, but they sure do suck in practice. At least, the Dance Dance Revolution game is full of empty promises. With the $25 cabinet, all you get are three songs that come out of a crappy little speaker, and a not-great display to match.

[BigRig Creates] endeavored to make it better, however, and managed to cram a Raspberry Pi 4 in the cabinet without disturbing the stock components too much. They did have to trim every extraneous piece of plastic from the inside of the cabinet and trim the I/O pins down, but it fit.

What didn’t fit are the fans that [BigRig Creates] needed once it was clear that it was necessary to overclock the Pi. As [BigRig Creates] points out, a custom PCB would have saved some room. And perhaps time. And definitely some wires.

Unfortunately, it wasn’t that simple on the software side. (It never is, is it?) Even getting the screen to work was no picnic. But in the end, it worked, and even survived a bunch of gamers testing it out at LTX. Check it out after the break.

Got an old PS2 DDR controller? You could make it play Simon instead.

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A picture of the bottom of the Pi 4 PCB, showing the three points you need to use to tap into the Pi 4 I2C bus going to the PMIC

Dead Raspberry Pi Boards, PMICs, And New Hope

Since the Raspberry Pi 3B+ release, the Pi boards we all know and love gained one more weakpoint – the PMIC chip, responsible for generating all the power rails a Pi needs. Specifically, the new PMIC was way more vulnerable to shorting 5V and 3.3V power rails together – something that’s trivial to do on a Raspberry Pi, and would leave you with a bricked board. Just replacing the PMIC chip, the MxL7704, wouldn’t help since the Raspberry Pi version of this chip is customized – but now, on Raspberry Pi forums, [Nefarious19] has reportedly managed to replace it and revive their Pi.

First off, you get a replacement PMIC and reflow it – and that’s where, to our knowledge, people have stopped so far. The next step proposed by [Nefarious19] is writing proper values into the I2C registers of the PMIC. For that, you’d want a currently-alive Pi – useful as both I2C controller for writing the values in, and as a source of known-good values. That said, if you go with the values that have been posted online, just having something like a Pi Pico for the I2C part ought to be enough.

[Nefarious19] reports a revived Pi, and this is way more hopeful than the “PMIC failures are unfixable” conclusion we’ve reached before. The instructions are not quite clear – someone else in the thread reports an unsuccessful attempt doing the same, and it might be that there’s a crucial step missing in making the values persist. However, such an advancement is notable, and we trust our readers to take the lead.

A week ago, [Mangy_Dog] on Hackaday Discord brought up fixing Raspberry Pi boards – given that the Raspberry Pi shortages are still an issue, digging up your broken Pi and repairing it starts making sense budget-wise. It’s no longer the ages where you could buy broken Pi boards by the hundred, and we imagine our readers have been getting creative. What are your experiences with fixing Raspberry Pi boards?

Showing a RAM chip being removed from a Pi 4 board, hot air gun in the shot. Area around the chip is covered with kapton tape.

Upgrade RAM On Your Pi 4, The Fun Way

The Raspberry Pi shortage has been a meme in hacker circles for what feels like an eternity now, and the Pi 4 seems to be most affected – though, maybe it’s just its popularity. Nevertheless, if you’re looking for a Pi 4, you would need to look far and wide – and things are way worse if you need the 8 GB version specifically. Or so we thought – [MadEDoctor] shows us that refreshing online store pages isn’t the only way, having successfully upgraded the RAM chip on the Pi 4 from 1 GB to 8 GB with help of a hot air gun.

These chips are BGA, and those might feel intimidating if you’re just starting out with hot air – however, we recommend you watch this video, as [MadEDoctor]’s approach is of the kind that brings BGA replacement to hobbyist level. First off, you get a compatible RAM chip somewhere like Aliexpress – lucky for us, those come equipped with a set of balls from the factory. The default balls are made of lead-free solder, and [MadEDoctor] reballed the RAM chip with leaded solder balls to lower the melting point, but it’s by no means a requirement that you do the same.

In fact, you only need a hot air gun, flux, a soldering iron and some solder wick to perform the replacement – no reballing equipment. Put some kapton or metal tape on the board for heat shielding, get the old chip off with hot air, use an iron with wick to clean the pads, add some flux, align the chip, then use hot air to solder a new chip onto the board. Replacing this chip can get your Pi 4 to the highly-sought-after 8 GB target – as an aside, we’re surprised that there was no configuration needed, as the Pi 4 booted right up and successfully recognized the extra RAM added.

We’d personally recommend preheating for such an upgrade – that said, this sure went without a hitch, and such a RAM swap method doesn’t require any stencils, solder paste or solder ball applications. Drop by the video description for compatible RAM chip part numbers, make sure you have your tacky flux and solder wick in order, and let [MadEDoctor] walk you through upgrading your Pi 4 the hacker way. Is this hack to your liking? Take it up a notch with this laptop soldered-in RAM upgrade journey, or that one RAM upgrade for an old GPU to comply to Apple’s whims.

Giant Spinning POV Christmas Tree

Spinning Holographic POV Christmas Tree Of Death

[Sean Hodgins] really harnessed the holiday spirit to create his very own Giant Spinning Holographic Christmas Tree (of Death). It’s a three-dimensional persistence-of-vision (POV) masterpiece, but as a collection of rapidly spinning metal elements, it’s potentially quite dangerous as well. As [Sean] demonstrates, the system can display other images and animations well beyond the realm of mere holiday trees.

Initial experiments focused on refining the mechanical structure, bearings, and motor. A 1/2 horsepower A.C. motor was selected and then the dimensions of the tree were “trimmed” to optimize a triangular frame that could be rotated at the necessary POV speed by the beefy motor.  A six-wire electrical slip ring allows power and control signaling to be coupled to the tree through its spinning central shaft.

The RGB elements are SK9888 LEDs also know as DotStar LEDs. DotStar LEDs are series-chainable, individually-addressable RGB LEDs similar to NeoPixels. However, with around 50 times the pulse width modulation (PWM) rate, DotStars are more suitable for POV applications than NeoPixels.  The LED chain is driven by a Raspberry Pi 4 single board computer using a clever system for storing image frames.

If deadly rotational velocity is not your cup of tea, consider this slower spinning RGB Christmas tree featuring a DIY slip ring. Or for more POV, may we suggest this minimalist persistence-of-vision display requiring only a few LEDs and an ATtiny CPU.

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A terminal window with a search for "Guineau Pig Olympics" is inset on a photo of an ortholinear keyboard attached by a yellow USB cable to a 70s aluminum and plastic Super 8 film editor/viewer. The device has a large screen on the right hand side, a silver grate on the left, and a tray at the bottom for slotting in film.

Super 8 Film Editor Reborn As A YouTube Terminal

We love hacks that give new life to old gadgets, and [edwardianpug]’s YouTube Terminal certainly fits the bill by putting new hardware inside a Super 8 film editor.

[edwardianpug] could have relegated this classy-looking piece of A/V history to a shelf for display, but instead she decided to refresh its components so it could display any YouTube video instead of just one strip of film at a time. The Boost-Box keeps the retrofuturistic theme going by using the terminal to search for and play videos via Ytfzf.

The original screen has been replaced by an 800×600 LCD, and the yellow USB cord gives a nice splash of color to connect the ortholinear keyboard to the device. Lest you think that this “ruined” a working piece of retro-tech, [edwardianpug] says that 20 minutes would get this device back to watching old movies.

Are you looking for more modern and retro mashups? Check out these Dice Towers Built In Beautiful Retro Cases, a Vacuum Tube and Microcontroller Ham Transmitter, or this Cyberdeck in a Retro Speaker.

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Cyberdeck Contest 2022: Gibson Rev 001 Thinks Outside The Pelican Case

As we’ve gushed previously in these pages, we saw an incredible turnout for our first-ever cyberdeck contest — so many cool ‘decks rolled in that it made judging them all quite the feat, and we would be remiss if we didn’t feature the favorites that, for whatever reason, didn’t make the cut. One of these is the aptly-named Gibson Rev 001 from [Gadjet].

This cyberdeck may be on the pocket-sized side of things, but don’t let that fool you, because it’s loaded with I/O and sensors galore. A Pimoroni Breakout Garden provides particle/smoke and pulse oximetry, temperature/pressure/altitude, an air quality sensor, and a UVA/UVB light sensor — plenty of feelers for judging conditions on the fly. As you might expect, the brains of the operation is a Raspi 4, which is running Twister OS.

We love the dual-display thing going on with the 7″ touchscreen and the color e-ink display — really gives it a cobbled-together-yet-polished, futuristic feel. May the rest of the post-apocalypse gadgetry have such clean lines and cheerful colors (if that’s what you’re into).