Retrotechtacular: Rocket Sleds

December 18, 2016 by 28 Comments

If you need to test rockets, missiles, or ejection-seat systems, your first instinct would be to shoot them up in the air and see what happens. But if you want data, film footage, or the ability to simply walk away from a test, you might consider running your experiment on a rocket sled.

The Holloman High Speed Test Track is a 15 km long stretch of meticulously straight railroad track located in the middle of the New Mexico desert, and bristling with measurement equipment. Today’s Retrotechtacular video (embedded below) gives you the guided tour. And by the way, the elderly colonel who narrates? He doesn’t just run the joint — he was one of the human test subjects put on a rocket sled to test the effects of high acceleration on humans. You can see him survive a run around 1:00 in. Continue reading “Retrotechtacular: Rocket Sleds” →

Raspberry Pi Zero smart projector

Smart Projector With Built-in Raspberry Pi Zero

December 18, 2016 by 16 Comments

You’ve heard of smartphones but have you heard of smart projectors? They’ve actually been around for a few years and are sort of like a TV set top box and projector combined, leaving no need for a TV. Features can include things like streaming Netflix, browsing in Chrome, and Skyping. However, they can cost from a few hundred to over a thousand dollars.

[Novaspirit]  instead made his own cheap smart projector. He first got a $70 portable projector (800×480 native resolution, decent for that price) and opened it up. He soldered an old USB hub that he already had to a Raspberry Pi Zero so that he could plug in a WiFi dongle and a dongle for a Bluetooth keyboard. That all went into the projector.

Examining the projector’s circuit board he found locations to which he could wire the Raspberry Pi Zero for power even when the projector was off. He lastly made the Raspberry Pi dual-bootable into either OSMC or RetroPie. OSMC is a Linux install that boots directly into a media player and RetroPie is a similar install that turns your Raspberry Pi into a gaming machine. You can see a timelapse of the making of it and a demonstration in the video after the break.

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Another Desktop LED Xmas Tree!

December 18, 2016 by 7 Comments

We love it when someone takes inspiration from one of our posts and comes up with their own twist on it. [Matthew] liked one builds he saw on Hackaday so much, he built his own LED desktop Xmas tree!

[Matthew] was inspired by [designer2k2]’s DIY desktop Xmas tree that was posted in October. To get started, he found a set of concentric WS2812 rings over on Ali Express. The five rings total 93 LEDs, plus a single WS2812 for the top of the tree. He also got a laser cut tree model from Thingiverse and had it cut, combining the LED rings with the tree in the final product

The whole thing running on a Digispark USB Development Board from DigiStump, the same as the original project. There aren’t many details in the video, but [Matthew] has put links to where he got the rings and the tree, the laser cutting service, a link to the DigiStump website as well as a link to [designer2k2]’s original tree project. There’s no source code yet, but [Matthew] says a link to it is coming along with some more pictures.

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Animatronic Cosplay Wings

December 17, 2016 by 32 Comments

In recent years, Cosplay as a hobby has seen improvement in the props department by leaps and bounds. Thanks in part due to the rise of the Maker culture and the easy availability of design and manufacturing tools and processes. Case in point is this awesome set of Animatronic Wings that programmer [Nelson Stoldt] built for his daughter who wanted to be Nightmare Moon.

[Nelson] had no idea what he’d gotten himself in to when he answered “Sure, I can do that”. Making motorized cosplay wings that open up to 8 feet wide and close again at the flick of a switch without weighing a ton is not a trivial project. The final rig did end up tipping the scales at just over 9 kgs, but we guess that’s a load that Cosplayers are used to hauling around.

Using a nifty program called Linkage, he played around with a few different design approaches until he found a mechanism that worked well. If you ever want to build one of [Theo Jansen]’s Strandbeest, give this program a spin. Armed with this information, and a spreadsheet to help determine the exact length of each linkage element, he modelled the project in Sketchup. The wings are operated by a scissor mechanism that is driven by a motorized screw operated sliding carriage. Wing position is measured by a potentiometer coupled to one of the wing elements. Basically, he just built a huge, powerful servo.

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3D Printed Circuit Boards… Sort Of

December 17, 2016 by 16 Comments

Comedian Demetri Martin does a bit about the phrase “sort of”. He says:

“Sort of’ is such a harmless thing to say… sort of. It’s just a filler. Sort of… it doesn’t really mean anything. But after certain things, sort of means everything. Like… after “I love you”… or “You’re going to live.”

SCADboard is an OpenSCAD library that lets you create 3D printable circuit boards…sort of. The library lays out like a breadboard with two bus bars on each side and a grid of rows and columns. OpenSCAD modules provide a way to create a board, ICs, LEDs, wires and other fundamental components. You set a few initial variables (like the board thickness) then your code looks like this:

 wire(1,bln,1,e, neg); // Neg left trace to LED
 led(1,e+1, 1,e+2, yellowled); // LED
 wire(1,f, 1,i, pos); // LED Pos
 wire(1,j, 1,brp, resistor); // Resistor
 
 wire(3,c,3,h, pos); // Cap Pos
 wire(4,c,4,h, neg); // LED Resistor

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The Engines Of Ingenuity

December 17, 2016 by 10 Comments

Every once in a while, we stumble on an amazing resource that’s not exactly new, but it’s new to us. This is the case, in spades, with The Engines of Our Ingenuity, a radio show that’s been running since 1988!

Each episode covers an invention or engineering marvel, and tells the story of how it came to be, and puts each device into its historical and cultural context. Want to get the lowdown on how we safely bring fire into the kitchen? Or the largest land transport vehicle, NASA’s crawler? And what’s up with lobsters anyway?

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PIC Mesh, Accessible Distributed Networking

December 17, 2016 by 6 Comments

Wireless networks have been reduced to a component, for most of us. We fit a device, maybe an ESP8266 module or similar, and as if by magic a network exists. The underlying technology has been abstracted into the firmware of the device, and we never encounter it directly. This is no bad thing, because using wireless communication without having to worry about its mechanics gives us the freedom to get on with the rest of our work.

It is however interesting once in a while to take a look at the operation of a real wireless network, and [Alex Wong], [Brian Clark], and [Raghava Kumar] have given us a project with the opportunity to do just that. Their PIC Mesh university project is a distributed wireless mesh network using 2.4GHz NRF24L01 transceiver modules and PIC32 microcontrollers. They have it configured for demonstration purposes with a home automation system at the application layer, however it could be applied to many other applications.

The real value in this project is in its comprehensive but easy to read write-up of the kind you’d expect from a university project. The front page linked above has an overview of how the mesh works, but there are also pages taking us through the hardware, the networking software layer, and the home automation application layer. If you have ever wanted to understand a simple mesh networking system, this is a good place to start.

We’ve covered quite a few mesh networks over the years, but sadly we can only link you to a few of them. We’ve had a mesh network using the Raspberry Pi, Project Byzantium’s “ad-hoc wireless mesh networking for the zombie apocalypse“, and a 1000-node Xbee network for testing purposes.