[CNLohr] Reverses Vive, Valve Engineers Play Along

[CNLohr] needs no introduction around these parts. He’s pulled off a few really epic hacks. Recently, he’s set his sights on writing a simple, easy to extend library to work with the HTC Vive VR controller equipment, and in particular the Watchman controller.

There’s been a lot of previous work on the device, so [Charles] wasn’t starting from scratch, and he live-streamed his work, allowing others to play along. In the process, two engineers who actually worked on the hardware in question, [Alan Yates] and [Ben Jackson], stopped by and gave some oblique hints and “warmer-cooler” guidance. A much-condensed version is up on YouTube (and embedded below). In the links, you’ll find code and the live streams in their original glory, if you want to see what went down blow by blow. Code and more docs are in this Gist.

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Flame Triodes Don’t Need Any Vacuum

There is a rich history surrounding the improvisation of electronic components. From cats-whisker foxhole radio detectors using razor blades through radio amateurs trying antique quartz lenses as crystal resonators and 1950s experimenters making their own point-contact transistors, whenever desirable components have been unavailable the ingenuity of hackers and makers has always sought to provide.

In an age when any component you might wish for is only a web browser and a courier package away, you might think there would be no need for such experiments. But it is in our curious nature to push the boundaries of what can be made without a factory at our disposal, so there are still plenty of ingenious home-made components under construction.

One such experiment came our way recently. It’s a few years old, but it’s a good one. [Nyle Steiner, K7NS] made a working triode without any form of vacuum, instead its medium is a flame. He’s demonstrated it as a rectifier, amplifier, and oscillator, and while it might not be the best triode ever it’s certainly one of the simplest.

In a traditional vacuum triode the current flows as electrons released from a hot cathode and are able to cross the space because there are no gas molecules for them to collide with. The flame triode has an abundance of gas, but the gasses within it and its immediate surroundings are also strongly ionized, and thus electrically conductive. Flame ionization detectors have exploited this phenomenon in scientific instruments for a very long time.

A roaring flame might not be the most practical thing to keep in your electronic equipment, but [Nyle]’s experiment is nonetheless an impressive one. He’s posted a video showing it in action, which you can see below the break.

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An Introduction To Valve’s Tracking Hardware

[Alan Yates] brought a demo of Valve’s new VR tech that’s the basis of the HTC Vive system to Maker Faire this year. It’s exceptionally clever, and compared to existing VR headsets it’s probably one of the best headtracking solutions out there.

With VR headsets, the problem isn’t putting two displays in front of the user’s eyes. The problem is determining where the user is looking quickly and accurately. IMUs and image processing techniques can be used with varying degrees of success, but to do it right, it needs to be really fast and really cheap.

[Alan] and [Valve]’s ‘Lighthouse’ tracking unit does this by placing a dozen or so IR photodiodes on the headset itself. On the tracking base station, IR lasers scan in the X and Y axes. By scanning these IR lasers across the VR headset, the angle of the headset to the base station can be computed in just a few cycles of a microcontroller. For a bunch of one cent photodiodes, absolute angles and the orientation to a base station can be determined very easily, something that has some pretty incredible applications for everything from VR to robotics.

Remember all of the position tracking hacks that came out as a result of the Nintendo Wii using IR beacons and a tracking camera? This seems like an evolutionary leap forward but in the same realm and can’t wait to see people hacking on this tech!

Solar Powered Circuit Waters Your Plants

 

If you want your plants to stay healthy, you need to make sure they stay watered. [Dimbit] decided to build his own solar powered circuit to help automatically keep his plants healthy. Like many things, there is more than one way to skin this cat. [Dimbit] had seen other similar projects before, but he wanted to make his smarter than the average watering project. He also wanted it to use very little energy.

[Dimbit] first tackled the power supply. He suspected he wouldn’t need much more than 5V for his project. He was able to build his own solar power supply by using four off-the-shelf solar garden lamps. These lamps each have their own low quality solar panel and AAA NiMH cell. [Dimbit] designed and 3D printed his own plastic stand to hold all of the solar cells in place. All of the cells and batteries are connected in series to increase the voltage.

Next [Dimbit] needed an electronically controllable water valve. He looked around but was unable to find anything readily available that would work with very little energy. He tried all different combinations of custom parts and off-the-shelf parts but just couldn’t make something with a perfect seal. The solution came from an unlikely source.

One day, when [Dimbit] ran out of laundry detergent, he noticed that the detergent bottle cap had a perfect hole that should be sealable with a steel ball bearing. He then designed his own electromagnet using a bolt, some magnet wire, and a custom 3D printed housing. This all fit together with the detergent cap to make a functional low power water valve.

The actual circuit runs on a Microchip PIC microcontroller. The system is designed to sleep for approximately nine minutes at a time. After the sleep cycle, it wakes up and tests a probe that sits in the soil. If the resistance is low enough, the PIC knows that the plants need water. It then opens the custom valve to release about two teaspoons of water from a gravity-fed system. After a few cycles, even very dry soil can reach the correct moisture level. Be sure to watch the video of the functioning system below. Continue reading “Solar Powered Circuit Waters Your Plants”

Sci-Fi Contest Roundup: The Valve Universe

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While most of the entries to our Sci-Fi contest come from movies and TV shows, a select few are based on the Valve universe, including a few builds based on Portal and Team Fortress 2.

Deadly neurotoxinGLADOS

Who wouldn’t want a gigantic articulated sociopathic robot hanging around? Two groups are building a clone of GLaDOs from the Portal series. and already the builds look really great.

[AmarOk], developed an open-source personal assistant called RORI that intends to be a more helpful version of GLaDOs, without all the testing and killing. He, along with [Peterb0y] and [n0m1s] are turning this personal assistant software into a GLaDOs replica.

Taking a slightly different tack, [Eric] and [jjyacovelli] built a GLaDOs-like robot with a camera in the ‘face’. This camera connects to a Google Glass and tracks the user’s head movements. There’s also a Nerf gun attached to the end of the robot body, triggered by double winking. Yep, it’s a heads-up display GLaDOs, perfect for punishing your test subjects.

Heavy load comin’ through!

Sentry

Not to be out done by a malevolent, hyper-intelligent artificial intelligence, [Tyler] and [Ryan] are building the cutest gat’ dern weapon in all of west Texas. It’s the level one sentry from Team Fortress 2, and the guys are turning one into a paintball sentry.

The TF2 sentry is a cute little bugger capable of motion tracking and perimeter defense, filling enemies with lead should they ever come too close.

While the end result probably won’t be as large or as heavy as the “official” real-life turret, a smaller table-top sized model is probably a little more practical. Even if it doesn’t live up to expectations, upgrading the sentry is simply a matter of whacking it with a wrench a few times.

 

There’s still time for you to cobble together an awesome Sci-Fi project and have a chance to win some awesome prizes.

A real car remote controlled with an Arduino… what could go wrong?

[Gilad] tipped us about his latest project, where he adds plenty of pneumatics and electronics into his wife’s car to remote control it.

The brake/throttle pedals are actuated by pistons controlled by electronic valves, and a standard DC motor is in charge of turning the wheel. The Arduino code tells us that the valves will be opened as long as the remote up/down channel is above/under given values. The frame is based on Festo aluminium profiles and we’re not sure where the mains used for the DC/DC converters is coming from.  As the valves use 24V and the motor 12V, standard N-Mosfets and power relays are used for voltage conversion. The remote controller [Gilard] used is actually 20 years old, so the output signal of the receiver isn’t actually really clean.

We do hope to never see this car on the road….

Build your own water rocket launcher

We feel like the days when you want to play in the water are far behind us. But if you can still find a warm afternoon here or there this water rocket launcher build is a fun undertaking. We figure most of the time spent on the project will be in shopping for the parts. They’re all quite common, and once you have them on hand it can be assembled in under an hour.

The concept is simple, but that doesn’t stop people from building rather complicated water rocket rigs. This one which [Lou] devised is rather simple but it does offer connections to a hose and air compressor (the alternative being to fill the bottle with water ahead of time and use a bike pump for air pressure). PVC is used to connect the two inputs to the bottle via a pair of valves. The bottle is held in place while water and air are applied. The launch happens when a pull on that rope  releases the bottle.

Check out the build process and bottle launch after the break. We think that rocket needs a few fins.

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