Author: Zoe Skyforest

3718 Articles

Fiber Optics, But… Wetter?

September 29, 2020 by 27 Comments

Fiber optics are a great way to transfer huge quantity of data at lightning speed. Thanks to the property of total internal reflection, which allows light to flow through a glass fiber like fluid through a pipe, they can be used for communications at long distances and form the backbone of modern communication networks. However, water is also able to pull off the total internal reflection party trick, and [Mike Kohn] decided to see if it could be used as a communication medium, too.

The experimental setup consists of an ATTiny85 that receives signals over its serial port, and outputs the received bits by flashing an LED. This LED is attached to a plastic tube filled with water. On the receiving end, another ATTiny85 reads the voltage level of a photodiode placed in the other end of the tube. When the ADC detects voltage over a certain level, it toggles a pin connected to the serial RX pin.

Hooking the setup to a pair of terminals, [Mike] was able to successfully transmit 9600 baud serial data through a tube full of water with just an LED and a small microcontroller. To verify the success, he ran the test again with an air-filled tube instead, which failed. In doing so, he proved that the water was doing the work.

We’ve seen other optical data hacks, too – like this awesome laser ethernet build. Video after the break.

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Eight Motors Can Sure Pump A Lot Of Water

September 29, 2020 by 28 Comments

Once upon a time, 3D printing was more of a curiosity than a powerful tool, with many printing trinkets and tchotchkes rather than anything of real use. However, over the years as technology and techniques have progressed, we now see more application-ready builds. This water pump from [Let’s Print] is a great example.

The pump consists of two major pieces – a drive unit, and an impeller. The drive unit consists of a gearbox that combines the power of eight electric motors, driving a single shaft. This is all achieved with striking yellow ABS gears in a black housing. The build video does a great job of explaining how to make the project work with different motors, and how to properly use the bolt adjuster to set the backlash on the gear train. The drive unit is then used to turn a 3D-printed impeller pump which is capable of delivering a great deal of water very quickly.

When fired up, the leaky assembly makes an awful racket and a huge mess, but sure as heck shifts a lot of water while it does so. Watching the water spray off the gears as it leaks through the bearings is a great sight, and it’s clear that the device works well. We’d love to see a cost and performance analysis of this pump versus a commercial offering.

While it’s certainly not the most rugged build, it’s a fun one that nevertheless gets the job done. We’d love to see this running a foam machine or a classic slip and slide. Video after the break.

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PC Cases Are Still Stuck In The Dark Ages, But We Can Fix This

September 28, 2020 by 182 Comments

In the dawning of the IBM PC era, the computer case was a heavy, stout thing. These were industrial machines, built with beefy paddle power switches, and weighing as much as a ton of bricks. Painted in only the ugliest beige, they set the tone for PC design for the next couple of decades.

At the turn of the millennium, the winds of change swept through. The Apple iMac redefined the computer as a hip, cool device, and other manufacturers began to reconsider their product aesthetics. Around the same time, the casemodding scene took off in earnest, with adherents building ever wilder battle stations for internet clout and glory.

With all the development that has gone in the last 40 years of the PC platform, we’ve seen great change and improvement in almost every area. But in building a new rig this past month, this writer discovered there’s one element of the modern PC that’s still trapped in the past.

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Food Dispenser Shakes And Rattles

September 27, 2020 by 17 Comments

[Elite Worm] follows a strict diet that involves regularly mixing dry ingredients in varying proportions. The task grew tedious, and thus automation became a tantalising prospect. Enter the DIY shaking food dispenser.

The machine has a simple touch screen interface, with an Atmega328P running the show behind the scenes. The user can store a series of profiles, which each correspond to a different mixture of four base ingredients. Dealing with dry ingredients like oats, chia, and flax, shaking is often necessary to get things moving. To achieve this, the rig packs a hefty DC motor up top, which turns an eccentric shaft, shaking the whole rig. Each ingredient hopper has a servo-controlled nozzle, so ingredients can be dispensed in turn, with a load cell in the base measuring the weight delivered.

It’s a neat system, though [Elite Worm] notes that the device shakes just a little too much, and suspects it won’t hold up in the long term. We suspect a less violent, higher frequency vibration might be less hard on the components, but we’re sure there’ll be some quality engineering going into the next build. We’ve seen [Elite Worm]’s work here before, too. Video after the break.

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DIYing A High End Camera Arm

September 27, 2020 by 21 Comments

One of the first purchases for anyone looking to shoot video should be a tripod. Key to getting clean and stable shots, they can nevertheless be limiting in their range of motion. Wanting something a little more high-end, but dissatisfied with the high cost of commercial options, [Alexandre Chappel] decided to build his own camera arm.

The build is based around square alumiunium tubing, with the high-tolerance material acting as the arm’s vertical and horizontal rails. 3D printed brackets and adapters are used to bolt everything together, along with several printed components used as drilling guides to help accurately machine the aluminium tubes. Adjustment is built into the carriages that travel along the rails, to help account for any slop in the 3D printed parts. A counterweight system is then installed to ensure the camera doesn’t hit the floor when not in the locked position.

It’s a tidy build, and one that has given [Alexandre] far more flexibility to shoot than his existing tripods. Additionally, adjusting the camera position is much quicker than before. Of course, when you’re building your own rigs, the sky is the limit. Video after the break.

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Rocket Plane Build Aims For High Speed Flight

September 27, 2020 by 19 Comments

[James Whomsley] likes flying, and likes flying fast. After reaching a speed of 114 miles an hour with an RC plane, he wanted to go further and break that record. To do so, he looked towards rocket power, and started a new build.

The design consists of a combination of 3D printed parts, laser-cut plywood bulkheads, and foamboard flight surfaces, with a few carbon fiber stiffeners thrown in here and there. For this early prototype, power is solely from hobby rocket motors, providing thrust for 1.6 seconds, meaning flight times are necessarily short. The craft is launched from an aluminium profile rail thanks to a 3D printed sliding guide pin.

Initial tests with two rocket motors were promising, leading to a second trial with a full six motors fitted. The thrust line was a little low, however, and a major pitch-up just after launch meant the plane only reached around 62 miles an hour. [James] still has a ways to go to beat his previous record, so intends to explore adding ducted fan propulsion to get the plane in the air before using the rockets as a speed booster in steady flight.

Of course, if you can’t lay your hands on rocket engines, you could always consider spinning up your own. (Or ditch the engine entirely.) Video after the break.

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An FPGA Video Player Built Just For Fun

September 26, 2020 by 8 Comments

Sometimes, projects are borne out of neccessity; a fix for a problem that needs to be solved. Other times, they’re done just for the love of creation and experimentation. [ultraembedded]’s FPGAmp media player falls under the latter, and served as a great learning experience along the way.

The aim of FPGAmp is to play back a variety of media files on the Arty A7 development board, based around the Xilinx Artix-7 FPGA. Capable of playing back MJPEG video at 800 x 600 resolution and 25 fps, it’s also able to play back MP3s as well for stereo audio. Demonstrating the device on Twitter, [ultraembedded] notes that the method of using an LED to do SPDIF optical audio output isn’t legit, but does work. A later update switches to using a dedicated audio output board with the Arty A7 platform, featuring an excellent song from The Cardigans.

Using a RISC V processor core and a hardware JPEG decoder, we imagine [ultraembedded] really sharpened their FPGA skills with this project. Particularly in the wake of the sale of ARM to NVIDIA, RISC V continues to gain relevance in the hardware community. We were lucky enough to feature a keynote at last year’s Supercon, with Megan Wachs speaking on the technology. Video after the break.

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