Visual Ear Demonstrates How The Cochlea Works

April 2, 2023 by Zoe Skyforest 13 Comments

The cochlea is key to human hearing, and it plays an important role in our understanding of complex frequency content. The Visual Ear project aims to illustrate the cochlear mechanism as an educational tool.

The cochlea itself is the part of the ear that converts the pressure waves of sound into electrical signals for the brain. Different auditory frequencies excite different parts of the cochlea. The cells in the different parts of the cochlea then send signals to the brain corresponding to the sound it has picked up.

The Visual Ear demonstrates similar behavior on a strip of addressable LEDs. Lower LEDs coded in the red part of the color spectrum respond to low frequency audio. Higher LEDs step through yellow, green, and up to blue, and respond to the higher frequencies in turn. This is achieved at a high response rate with the use of a Teensy 4.0 running a Fast Fourier Transform on incoming audio, and then outputting signals to run a string of WS2812B LEDs. The result is a visual band display of 104 bands spanning 43 Hz up to 16,744 Hz, which covers most but not all of the human range of hearing.

It’s an impressive display, and one that makes a great music visualizer, too. When teaching the physics of human hearing and the cochlea, we can imagine such a tool would be quite useful.

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Design Files Released For The PR2 Robot

April 2, 2023 by Zoe Skyforest 9 Comments

It’s always great fun to build your own robot. Sometimes, though, if you’re doing various projects or research, it’s easier to buy an existing robot and then use it to get down to business. That was very much the role of the Willow Garage PR2, but unfortunately, it’s no longer in production. However, as covered by The Robot Report, the design files have now been released for others to use.

The PR2 was built as an advanced platform with wide-ranging capabilities. It was able to manipulate objects with its 7-degrees-of-freedom end effectors, as well as visualize the real world with a variety of complex sensor packages. Researchers put it to work on a variety of tasks, from playing pool to fetching beers and even folding laundry. The latter one is still considered an unsolved problem that challenges even the best robots.

Rights to the PR2 robot landed in the hands of Clearpath Robotics, after Willow Garage was shut down in 2014. Clearpath is now providing access to the robot’s design files on its website. This includes everything from wiring diagrams and schematics, to assembly drawings, cable specs, and other background details. You’ll have to provide some personal information to get access, but the documentation you desire is all there.

We actually got our first look at the PR2 robot many years ago, way back in 2009. If you decide to build your own from scratch, be sure to hit us up on the tipsline.

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Rubik’s Cube Solver Does It In 4.56 Seconds

April 2, 2023 by Zoe Skyforest 14 Comments

Solving Rubik’s Cubes is a learnable skill. However, to compete at the top level, you’ll have to train hard. Speed cubers can solve a 3×3 cube in under ten seconds these days, after all. [aaedmusa] was a long way off that speed, but his robot is an absolute demon that solves at a rapid pace.

The robot relies on a Teensy 4.1 microcontroller to run the show, paired with its Ethernet kit for connectivity. It runs six stepper motors via TMC2208 drivers, enabling it to directly actuate each face of the cube. Purists will note, however, that the steppers are fitted with adapters that slot directly into modified center squares on the cube. A regulation Rubik’s, this is not.

The design doesn’t feature a machine vision system to capture the state of the cube. Instead, the cube’s status must be input to a web app on an attached computer. Once the cube’s state is loaded into the program, though, the mechanical job of solving the cube can be achieved in under five seconds. Even with six actuators, that’s not fast enough to beat the human world record of 3.47 seconds, but it’s still pretty darn good.

It’s funny to think that way back in 2011, both robots and humans were so much slower at solving cubes. If only all the world’s problems were as simple as a jumbled up toy from the 1970s.

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Building An Energy Sword Replica From Halo

April 1, 2023 by Zoe Skyforest No comments

A good many of us whiled away the hours of our youths playing Swords Only deathmatch in Halo 2. The Energy Sword, aka the Plasma Sword, was the star of the show, with its devastating glowing blades granting us scoreboard domination. [Arnov Sharma] has now built a quality replica of this science-fiction weapon.

The build starts with a 3D design drawn up in Fusion 360. The parts are then 3D printed, with opaque filament used for the handle and translucent PLA filament for the “blade”. Inside the blade elements are twenty WS2812B LEDs, creating the characteristic glow that made the Energy Sword so tantalizing to find in game. An ATtiny85 is charged with running the LEDs, with the aid of an IP5306 chip to act as a boost converter for the lithium-ion battery supplying the juice.

[Anton] admits that the sword was built for the sole purpose of beautifying his maker space. That’s something we can respect, because we’d love to have one hanging on the wall at home. We’ve featured some other fun gaming replicas before, too.

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Blender And OpenEMS Teamed Up Make Stunning Simulations

April 1, 2023 by Zoe Skyforest 5 Comments

There’s tons of theory out there to explain the behavior of electronic circuits and electromagnetic waves. When it comes to visualization though, most of us have had to make do with our lecturer’s very finest blackboard scribbles, or some diagrams in a textbook. [Sam A] has been working on some glorious animated simulations, however, which show us various phenomena in a far more intuitive way.

The animations were created in Blender, the popular 3D animation software. As for the underlying simulation going on behind the scenes, this was created using the openEMS platform. [Sam] has used openEMS to run electromagnetic simulations of simple circuits via KiCAD. From there, it was a matter of finding a way to export the simulation results in a way that could be imported into Blender. This was achieved with Paraview software acting as a conduit, paired with a custom Python script.

The result is that [Sam] can produce visually pleasing electromagnetic simulations that are easy to understand. One needn’t imagine a RF signal’s behaviour in a theoretical coax cable with no termination, when one can simply see what happens in [Sam]’s animation.

Simulation is a powerful tool which is often key to engineering workflows, as we’ve seen before.

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Working With Old High-Voltage EPROMs Is Fussy

March 31, 2023 by Zoe Skyforest 19 Comments

EPROMs, those UV-erasable memory chips of the 80s and 90s, once played a crucial role in countless electronic devices. They’ve become relics of a bygone era, but for enthusiasts of vintage electronics, the allure of these light-sensitive devices remains strong. Today, we’re diving into [Kevin Osborn]’s nostalgic journey as he uncovers the secrets of old EPROMs loaded with Atari 7800 code.

[Kevin] used to work at General Computer Company, which produced the Atari 7800 and several games for the system. Thus, he had a handful of old carts and development EPROMs sitting up in his attic along with an old console. Recently, he decided to try and uncover what was on the EPROMs and begun an investigation. They wouldn’t run in his Atari, and he quickly realized why: the EPROMs weren’t cryptographically signed, so the system wouldn’t load them. Continue reading “Working With Old High-Voltage EPROMs Is Fussy” →

Tiny Yet Functional Bike Built From Scratch

March 31, 2023 by Zoe Skyforest 10 Comments

Sometimes, you just want to go ride your bike in the great outdoors, but you can’t be bothered throwing it in the back of the car. That wouldn’t be a problem if you rode this latest build from [The Q]: a bike small enough to fit in a handbag.

The build starts by customizing a rollerblade wheel to act as the driven rear wheel of the bike. It’s fitted with a tiny sprocket allowing it to be chain driven. Welding some steel tubes then nets a small diamond-layout bike frame. It’s fitted with a chain ring, pedals, and steering assembly just like a full-sized bike, just in absolute miniature.

Riding the bike is “uncomfortable,” in [The Q]’s own terms, but entirely possible. It basically requires the same level of contortion and technique as displayed by the clowns of your local circus. Don’t expect to use it as viable transportation, though. Walking would be much faster.

We’ve seen [The Q] build some wild bikes before, too, like this great hubless design. Video after the break.

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