An Entirely Frivolous Way To Measure Data

September 22, 2021 by Zoe Skyforest 23 Comments

[lexie] is a librarian, and librarians live in the real world. They’re not concerned with vague digital notions about the size of data, but practical notions of space. Thus, she created a tool to answer an important question: how long do your shelves need to be if you’re storing all your information on 3.5″ floppy disks?

It’s a great question, and one we find ourselves asking, well, pretty much never. [lexie]’s tool is also built using modern web technologies, and 3.5″ floppy disks were never really used for bulk storage, either. It just makes the whole thing all the more frivolous, and that makes it more fun.

You can key in any quantity from megabytes to exabytes and the tool will spit out the relevant answer in anything from millimeters to miles as appropriate. Despite the graphics on the web page, it does assume rational shelving practices of placing disks along the shelves on their thinner 4 mm edge.

We’d love to see a expanded version that covers other storage methods, like tape, hard drives, or burnt media. It could actually become pretty useful for those building their own mass storage farms at home. With CHIA cryptocurrency that could become more popular, even if it does run us all out of hard drives along the way. Altnernatively, you might consider hooking up a floppy controller for your Raspberry Pi.

Building A Custom Linux Single Board Computer Just To Play Spotify

September 22, 2021 by Zoe Skyforest 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!]

Spooky Coffin Bell Spooks Passers By On Halloween

September 21, 2021 by Zoe Skyforest 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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Green Roofs Could Help Improve Solar Panel Efficiency

September 20, 2021 by Zoe Skyforest 83 Comments

There’s been a movement in architecture over the past couple of decades to help tie together large urban developments with plant life and greenery. We’ve seen a few buildings, and hundreds more renders, of tall skyscrapers and large buildings covered in vegetation.

The aesthetic is often a beautiful one, but the idea is done as much for its tangible benefits as for the sheer visual glory. Naturally, there’s the obvious boost from plants converting carbon dioxide into delicious, life-giving oxygen. However, greenery on the roofs of buildings could also help improve the output of solar installations, according to a recent study from Sydney, Australia.

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Lego Submarine Gets Balloon Ballast System

September 19, 2021 by Zoe Skyforest 21 Comments

Lego is a fun building block which vast numbers of the world’s children play with every day. However, the mechanical Technic line of Lego building blocks has long offered greater options to the budding engineer. [Brick Experiment Channel] is one such soul, working hard on their latest Lego submarine.

The sub is built inside of a glass food container, chosen for its removable plastic lid with a watertight seal. This keeps all the mechanics dry, as well as the custom electronics built to allow a 27MHz RC controller to send signals to the Lego electronics. This is key as higher frequency radios such as Bluetooth or WiFi can’t penetrate water nearly as well.

A magnetic coupling fitted to a Lego motor is used to drive the propeller in the water without the leaks common when trying to seal a rotating shaft. A second coupling on a Lego servo along with a creative steering arrangement allows the propeller to be turned to steer the craft.

The ballast system is simple. A balloon is filled by a Lego motor running an air pump, capable of 3.0 mL a second and capable of creating a maximum pressure of 2.0 bar. When the balloon is inflated, the buoyancy goes up and the sub rises. Run the motor the other way and the balloon is emptied by a clever clutch and valve arrangement, reducing buoyancy and causing the sub to sink.

The sub isn’t perfect. Maintaining a set depth underwater can be difficult with the rudimentary ballast system, perhaps as the balloon changes shape with varying water pressure. Sometimes, Lego axles slip out of their gears, too, and the radio only works for a few meters under water.

However, simply building a Lego sub of any sort is a remarkable feat. It’s interesting to see the variances in the design compared to earlier projects from [Brick Experiment Channel], too, as we’ve featured their earlier subs before. Video after the break.

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Putting An Afterburner On An Electric Ducted Fan

September 17, 2021 by Zoe Skyforest 30 Comments

Afterburners are commonly agreed to be the coolest feature of military fighter aircraft. Injecting raw fuel into the exhaust stream of a jet engine, afterburners are responsible for that red-hot flaming exhaust and the key to many aircraft achieving supersonic flight. [Integza] wanted to see if the same concept could be applied to an electric ducted fan, and set out to find out.

Of course, building an afterburner for an EDF does add a lot of complication. A flame tube was installed downstream of the EDF, fitted with a brass tube drilled carefully to act as a fuel injector. The flame tube was also fitted with an automotive glow plug in order to ignite the fuel, which was lighter refill gas straight from a can. The whole assembly is wrapped up inside a clear acrylic tube that allows one to easily see what’s happening inside with the combustion.

Results were mixed. While the fuel did combust, but in a rather intermittent fashion. In proper operation, an afterburner would run with smooth, continuous, roaring combustion. Additionally, no thrust measurements were taken and the assembly barely shook the desk.

Thus, if anything, the video serves more as a guide of how to burn a lot of lighter gas with the help of an electric fan. The concept does has merit, and we’ve seen past attempts, too, but we’d love to see a proper set up with thrust readings with and without the afterburner to see that it’s actually creating some useful thrust. Video after the break. Continue reading “Putting An Afterburner On An Electric Ducted Fan” →

Retrotechtacular: The Dangers Of Confined Spaces

September 17, 2021 by Zoe Skyforest 31 Comments

Many people find themselves working in confined spaces every day, whether it be in sewer systems, drains, or other tight spots. These areas come with their own unique risks to life and limb that must be carefully considered in order to avoid disaster.

To this end, the Worker’s Compensation Board of British Columbia, known as WorkSafe BC, produced a video on the dangers of working in these areas. Confined Spaces, Deadly Spaces highlights how these areas can kill, and the right way to work around these hazards.

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