Simulating VR Obstacles With Wheelchair Brakes

June 1, 2017 by John Baichtal 6 Comments

[Joey Campbell] is studying for his PhD at the Bristol Interaction and Graphics Lab, focusing on the interplay between real and virtual objects within the realm of exergaming–“gamercising” where physical motion and effort drives the game. The goal is to make the physical effort seem to correspond with what’s seen on the headset.

[Joey] set up a test rig where an exercise bike’s gears were adjusted based on the terrain encountered, seeking to find out if that realism inspired a greater feeling of immersion. He also provided some test subjects a HUD with their heart rate and other stats, to see if that encouraged gamers to exercise more.

In his current project, [Joey] has equipped a wheelchair with a pair of Arduino-controlled servos that squeeze the brakes to simulate an obstacle. In the VR realm, a player pushes the wheelchair toward a virtual block and the brakes engage, requiring the player push harder to bypass the obstacle.

One imagines the possibilities of games designed for specifically for wheelchairs. The Eyedrivomatic wheelchair that won the 2015 Hackaday Prize sounds perfect for the job!

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Current Sink Keeps The Smoke In

June 1, 2017 by Bryan Cockfield 11 Comments

One of the most versatile tools on anyone’s work bench, at least as far as electrical projects are concerned, is a power supply. Often we build our own, but after we’ve cobbled together some banana jacks with a computer’s PSU or dead-bug soldered a LM317 voltage regulator to a wall wart, how will that power supply perform? Since it’s not desirable to use a power supply that’ll let the smoke out of everything it powers (or itself, for that matter) a constant current sink, or load, can help determine the operating limits of the power supply.

[electrobob] built this particular current sink from parts he had lying around. The theory of a constant current sink is relatively straightforward so it’s easily possible to build one from parts out of the junk drawer, provided you can find a few transistors, fuses, an op amp, and some heat sinks. The full set of schematics that [electrobob] designed can be found on his main project page. He’s also gone a step further with this build as well, since he shorted out his first prototype and destroyed some of the transistors. But, using a few extra transistors in his design also improves the safety and performance of the load, so it’s a win-win.

This constant current load also has the added feature of being able to interface with a waveform generator (an Analog Discovery, specifically) and as a result can connect and disconnect the load quickly. If you aren’t in need of an industrial-grade constant current sink and you have some spare parts lying around, this would be a great one to have around the work bench.

Shoot Video In 26 Different Directions

May 31, 2017 by John Baichtal 9 Comments

[Mark Mullins] is working on a project called Quamera: a camera that takes video in every direction simultaneously, creating realtime 3D environments on the fly.

[Mark] is using 26 Arducams, arranging them in a rhombicuboctahedron configuration, which consists of three rings of 8 cameras with each ring controlled by a Beaglebone; the top and bottom rings are angled at 45 degrees, while the center ring looks straight out. The top and bottom cameras are controlled by a fourth Beaglebone, which also serves to communicate with the Nvidia Jetson TX1 that runs everything. Together, these cameras can see in all directions at once, with enough overlap for provide a seamless display for viewers.

In the image to the right, [Mark] is testing out his software for getting the various cameras to work together. The banks of circles and the dots and lines connecting to them represent the computer’s best guess on how to seamlessly merge the images.

If you want to check out the project in person, [Mark] will be showing off the Quamera at the Dover Mini Maker Faire this August. In the meantime, to learn more about the Jetson check out our thorough overview of the board.

ZeroBot Is As Simple As It Gets

May 31, 2017 by Cameron Coward 22 Comments

Usually at Hackaday we like to post projects that are of interest because of their complexity. That’s especially true for robots — the more motors and sensors the better. But, occasionally we come across a project that’s beautiful because of its simplicity. That’s the case with [Max Kern]’s ZeroBot, recently posted over on Hackaday.io.

The ZeroBot breaks the essence of a robot down to just the essentials: a Raspberry Pi Zero W for the brains, a driver and two motors for movement, a battery for power, and a camera to see. The chassis is made completely of parts that are easily 3D-printable. The Zero W creates a WiFi access point that users can connect to on a computer or smart phone, and subsequently provides FPV control.

This project is reminiscent of the starter robot kits many of us began our hacking lives with, and it’s a great teaching tool for kids. Print the parts and you can have the robot built-in an afternoon, while still being fun enough to actually play with when you’re done. After the physical robot is built, the possibilities for programming and controlling it are endless.

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A Water Jet Cutter From A Cheap Pressure Washer

May 31, 2017 by Jenny List 67 Comments

We’ve become used to CNC mills and 3D printers becoming staples of our workshops, and thanks to the wonders of international trade even a modest laser cutter is not beyond the reach of most experimenters. But there is one tool that has so far evaded all but either commercial operations or the extremely well-heeled, the water cutter. These machines use a high-pressure water jet, usually carrying a stream of abrasive particles, to cut through the material placed beneath them. From our perspective they are interesting in that they can cut metal, something not normally possible with the laser cutters within our reach.

A water cutter is something you might think would be impossible for an experimenter to make for themself, but [Applied Science] is on hand to disprove that notion. He’s taken a cheap pressure washer, and modified it to produce a much higher water pressure for a water cutting head.

His very detailed description of the modifications makes for an extremely interesting watch, and we’ve placed the video below the break. The higher pressure is achieved by modifying the washer’s pressure on-off switch with a newly-machined sleeve and a stronger spring. The description of how the washer switch works is interesting in itself. Then we are treated to a complete teardown of a water cutting head, with abrasive feed, tungsten carbide tube, and ruby nozzle. This last component is surprisingly cheap. He then gives us a run-down of its design, particularly with respect to choosing the size of the orifices to match the pump. Finally we take a look at his abrasive feed system, and the plastic funnel he uses to keep water flow back out of his hopper.

For now the cutter is static, but his obvious next step is to bring it to some form of CNC table. If this project brings water cutting one step closer to the masses, we can’t wait!

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Hijacking The Sonoff OTA Mechanism

May 31, 2017 by Lewin Day 25 Comments

ITEAD’s Sonoff line is a range of Internet-of-Things devices based around the ESP8266. This makes them popular for hacking due to their accessibility. Past projects have figured out how to reflash the Sonoff devices, but for [mirko], that wasn’t enough – it was time to reverse engineer the Sonoff Over-The-Air update protocol.

[mirko]’s motivation is simple enough – a desire for IoT devices that don’t need to phone home to the corporate mothership, combined with wanting to avoid the labor of cracking open every Sonoff device to reflash it with wires like a Neanderthal. The first step involved connecting the Sonoff device to WiFi and capturing the traffic. This quickly turned up an SSL connection to a remote URL. This was easily intercepted as the device doesn’t do any certificate validation – but a lack of security is sadly never a surprise on the Internet of Things.

After capturing the network traffic, [mirko] set about piecing together the protocol used to execute the OTA updates. After a basic handshake between client and server, the server can ask the client to take various actions – such as downloading an updated firmware image. After determining the messaging format, [mirko] sought to create a webserver in Python to replicate this behaviour.

There are some pitfalls – firmware images need to be formatted slightly differently for OTA updates versus the usual serial upload method, as this process leaves the stock bootloader intact. There’s also the split-partition flash storage system to deal with, which [mirko] is still working on.

Nevertheless, it’s great to see hackers doing what they do best – taking control over hardware and software to serve their own purposes. To learn more, why not check out how to flash your Sonoff devices over serial? They’re just an ESP8266 inside, after all.

Hackaday Prize Entry: 3D Printed Mini-Lathe

May 31, 2017 by Lewin Day 20 Comments

Lathes can be big, powerful, dangerous machines. But sometimes there’s a call for making very small parts out of soft materials, like plastic and wood. For jobs like this, you could use something like this 3D printed mini-lathe.

The benefits of 3D printing a tool like this are plentiful. The design can be customized and refined by the end user; [castvee8] notes that the machine can be made longer simply by increasing the length of the lead screw and guide rails. The machine does rely on some metal parts and a motor; but the real power here is that if you can’t source the exact components, you can always customize the files to suit what you have on hand.

[castvee8] aimed to make the entire build as easy as possible for the novice – even the motor and speed controller are off-the-shelf modules. It’s a testament to the golden age we live in that an entire lathe can be built out of modules and 3D printed parts. The project makes up another member of the family of 3D printed tools [castvee8] is showing off on Hackaday.io.