Building A Custom Linux Single Board Computer Just To Play Spotify

September 22, 2021 by 31 Comments

If you want to hook up an existing stereo or amplifier to Spotify, there’s a fair few options on the market. You can even just order a Raspberry Pi and be done with it. [Evan Hailey] went his own way, however, and built his own Spotify Box from scratch.

[Evan] even made this tidy wooden enclosure, learning yet more along the way!
Housed inside a tidy little wooden enclosure of his own creation, the Spotify Box can turn any amplifier into a remote-controlled Spotify player via Spotify Connect. Pick the songs on your smartphone, and they’ll play from the Spotify Box as simple as that.

The project is based on the Allwinner V3S, a system-on-chip with a 1.2GHz ARM-Cortex-A7 core, 64MB of DDR2 RAM, and an Ethernet transceiver for good measure. There’s also a high-quality audio codec built in, making it perfect for this application. It’s thrown onto a four-layer PCB of [Evan’s] own design, and paired with a Wi-Fi and BlueTooth transceiver, RJ-45 and RCA jacks, a push-button and some LEDs. There’s also an SD card for storage.

With a custom Linux install brewed up using Buildroot, [Evan] was able to get a barebones system running Spotifyd while communicating with the network. With that done, it was as simple as hooking up the Spotify Box to an amp and grooving out to some tunes.

Along the way, [Evan] learned all about compiling drivers and working with embedded Linux, as well as how to take a bare SoC and build it into a fully-functional single-board computer. When someone else says they “made” a Spotify player, he presumably gets to clear his throat.

If you fancy retro computers, consider interfacing Spotify with your classic Mac instead!

[Thanks to Jay Carlson for the tip!]

Is There A Simpler Aircraft Than This Electric Paramotor?

September 22, 2021 by 52 Comments

The dream of taking to the air has probably ensnared more than a few of us, but for most it remains elusive as the safety, regulatory, and training frameworks surrounding powered flight make it not an endeavour for the faint-hearted. [Justine Haupt] has probably delivered the simplest possible powered aircraft with her Blimp Drive, a twin-prop electric add-on for her paragliding rig that allows her to self-launch, and to sustain her flights while soaring.

It takes the form of a carbon-fibre tube with large drone motors and props U-bolted to each end, and a set of brackets in the centre of laid carbon fibre over 3D-printed forms to which the battery and paraglider harness are attached. The whole thing is lightweight and quiet, and because of the two contra-rotating propellers it also doesn’t possess the torque issues that would affect a single propeller craft.

We’re not fliers or paragliders here at Hackaday, so our impression of the craft in use doesn’t come from the perspective of a pilot. But its simplicity and ease of getting into the air looks to be unmatched by anything else, and we have to admit a tinge of envy as in the video below the break she flies over the beach that’s her test site.

If you recognise Justine from past Hackaday articles, you’re on the right track. Probably most memorable is her rotary cellphone.

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Retro TV Shows Off Family Memories With Raspberry Pi

September 21, 2021 by 21 Comments

Fascinated by the look and feel of vintage electronics, [Democracity] decided to turn an old Sony Micro TV into a digital picture frame that would cycle through old family photos in style. You’d think the modern IPS widescreen display would stick out like a sore thumb, but thanks to the clever application of a 1/16″ black acrylic bezel and the original glass still installed in the front panel, the new hardware blends in exceptionally well.

Driving the new display is a Raspberry Pi 4, which might sound overkill, but considering the front-end is being provided by DAKboard through Chromium, we can understand the desire for some extra horsepower and RAM. If it were us we’d probably have gone with a less powerful board and a few Python scripts, and of course there are a few turn-key open source solutions out there, though we’ll admit that this is probably faster and easier to setup.

[Democracity] provides some general information on how he took apart the TV and grafted in the new gear, but of course the exact steps will vary a bit depending on which old TV you end up sending to the big parts bin in the sky. We did like that he made sure to keep all the mechanisms for the buttons and knobs intact, so even if they don’t do anything, you can still fiddle around with them.

Otherwise, his steps for setting up a headless Chromium instance are probably more widely applicable. As are the tips about setting up this particular LCD module and getting the display rotated into the proper orientation. If you just follow along for that part of the guide, you can spin up your own stand-alone Raspberry Pi DAKboard endpoint to take the service for a test drive.

It probably won’t come as much of a surprise to hear that this isn’t the first time [Democracity] has upgraded a piece of vintage hardware. Back in 2017, we covered this gorgeous art deco speaker that he outfitted with RGB LEDs and an Amazon Echo Dot. As with the previous post, it’s likely some commenters will be upset that a vintage piece of gear has been gutted for this project. But we’d counter that by saying his family is going to get a lot more enjoyment out of this beautiful piece of hardware now than they would have if it was still collecting dust in a closet.

Spooky Coffin Bell Spooks Passers By On Halloween

September 21, 2021 by 3 Comments

Being buried alive isn’t fun, we imagine. Fear of it led to the development of various safety coffin ideas in the 18th and 19th centuries, and [Glen Akins] wonderful Halloween prop riffs on that tradition today. 

The safety coffin was a simple solution for those afraid that this might happen to them. One concept had a bell which was installed above freshly dug graves with a string extending into the coffin. One who found themselves accidentally buried alive could then pull the string to ring the bell and summon help.

[Glen’s] installation eliminates the coffin and the dead body, and simply mounts a bell on a post. Inside, there’s an ultrasonic rangefinder that detects passers by. When someone walks closely enough to the prop, a microcontroller triggers a servo which rings the bell with a haunting urgency.

It’s a simple build, but appropriately installed with its LED lighting, it really does pop. It would be a wonderful way to add atmosphere and mood to a Hallowe’en party or haunted house. We’ve seen some great Hallowe’en hacks over the years, and some of the best are pumpkins. Video after the break.

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A weld bead laid down with homemade CO2

Cooking Up A Batch Of Homebrew Welding Gas

September 21, 2021 by 31 Comments

You know the feeling — you’re making good progress on a weekend project, you’re really in the groove, things are going right. Right up until you run out of That One Thing™ that you can’t do without, the only store that sells it is closed, and you get a sudden case of whiplash as your progress hits a virtual brick wall.

Of course, every challenge holds the opportunity to hack your way around it, which is how [Lucas] ended up building this carbon dioxide generator. The “IG” in MIG welding stands for the “inert gas” that floods the weld pool and keeps the melted metal — the “M” in MIG — from rapidly oxidizing and ruining the weld. Welders often use either straight CO2 or a mix of CO2 and argon as a MIG shielding gas, which they normally get from a commercial gas supplier, generally on non-weekend days.

[Lucas] turned to grade-school chemistry for his CO2 generator, using the vigorous reaction of baking soda and vinegar to produce the gas. Version one was sketchy as all get-out; the second iteration still had some sketch factor thanks to the use of ABS pipe, but the inclusion of a relief valve should prevent the worst from happening. After some fiddling with how to get the reagents together in a controlled fashion, [Lucas] was able to generate enough CO2 to put down a decent bead — a short one, to be sure, but the video below shows that it worked.

Could this be scaled up to something for practical use? Probably not. But it’s cool to see what’s possible, and something to file away for a rainy day. And maybe [Lucas] can use this method to produce CO2 for his homemade laser tube. But again, probably not.

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Mini Wireless Thermal Printers Get Arduino Library (and MacOS App)

September 21, 2021 by 24 Comments

[Larry Bank]’s Arduino library to print text and graphics on BLE (Bluetooth Low Energy) thermal printers has some excellent features, and makes sending wireless print jobs to a number of common models about as easy as can be. These printers are small, inexpensive, and wireless. That’s a great mix that makes them attractive for projects that would benefit from printing out a hardcopy.

It’s not limited to simple default text, either. Fancier output can be done using Adafruit_GFX library-style fonts and options, which sends the formatted text as graphics. You can read all about what the library can do in this succinct list of concise functions.

But [Larry] hasn’t stopped there. While experimenting with microcontrollers and BLE thermal printers, he also wanted to explore talking to these printers from his Mac using BLE directly. Print2BLE is a MacOS application that allows dragging image files into the application’s window, and if the preview looks good, the print button makes it come out of the printer as a 1-bpp dithered image.

Small thermal printers make for neat projects, like this retrofitted Polaroid camera, and now that these little printers are both wireless and economical, things can only get easier with the help of a library like this. Of course, if that’s all starting to look a little too easy, one can always put the thermal back in thermal printing by using plasma, instead.

Bringing The Quake Flicker To Life With A Hacked Light

September 21, 2021 by 14 Comments

If you ever feel a pang of shame because you’ve been reusing the same snippets of code in your projects for years, don’t. Even the big names do it, as evidenced by the fact that code written to govern flickering lights back in 1996 for Quake is still being used in AAA titles like 2020’s Half-Life: Alyx. In honor of this iconic example of digital buck-passing, [Rodrigo Feliciano] thought he’d port the code in question over to the Arduino and recreate the effect in real-life.

Since the Quake engine has been released under the GPLv2, it’s easy to pull up the relevant section of the code to see how the lighting was configured. Interestingly, lighting patterns were implemented as strings, where the letters from a to z referenced how bright the light should appear. So for example, a strobe light that goes between minimum and maximum brightness would be written as “aaaaaaaazzzzzzzz”, while a flickering light could be represented with the string “nmonqnmomnmomomno“.

An emergency light provided the LEDs and enclosure.

This ended up being very easy to implement on the Arduino in just a few lines, as [Rodrigo] simply had to assign each letter in the string a numerical value between 0 and 255 using map, and then use the resulting number to set the LED brightness with analogWrite.

With the code written, [Rodrigo] then had to put the hardware together. He stripped down a basic emergency light to get an array of white LEDs and a handy enclosure. He also wired up a simple transistor circuit on a scrap of perfboard so the Arduino Pro Mini could control all the LEDs from a single GPIO pin. Combined with a long USB cable to power it, and he’s got a perfect desk accessory for late-night gaming sessions.

In the video below you can see the final result, which [Rodrigo] has even synced up to footage from the classic 1996 shooter. The light makes for an interesting conversation piece, but we think the logical next step is to work this technique into an ambilight-like system to really make it feel like you’re wandering down those dimly lit corridors.

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