[Jeri] Spills The Beans On Her AR Glasses

May 31, 2013 by 52 Comments

AR

In the last year, [Jeri Ellsworth] has been very busy. She was hired by Valve, started development of an augmented reality system, fired by Valve, and started a new company with [Rick Johnson] to bring her augmented reality glasses to the market. On the last Amp Hour podcast she spilled the beans on what went down at Valve, how her glasses work, and what her plans for the future are.

[Jeri] and [Rick]’s castAR glasses aren’t virtual reality glasses like the Oculus Rift or other virtual reality glasses that cut you off from the real world. The castAR glasses preserve your peripheral vision by projecting images and objects onto a gray retro-reflective mat and allows you to interact with a virtual environment with an electronic wand. So far, there are a few demos for the castAR system; a Jenga clone, and a game of battle chess called Team For Chess, a wonderful reference to Valve’s hat simulator.

The electronics inside the castAR glasses are fairly impressive; new frames are drawn on the retro-reflective surface at 100 Hz, positioning accuracy is in the sub-millimeter range, and thanks to [Jeri]’s clever engineering the entire system should be priced at about $200. Not too bad for an awesome device that can be used not only for D&D and Warhammer, but also for some very cool practical applications like visualizing engineering models of 3D prints before they’re printed.

18-year-old Builds Functioning Submarine

May 30, 2013 by 92 Comments

teen-builds-submarine

[Justin Beckerman] built a functioning one-man submarine. The thing is, this isn’t the first one that he’s built. Looking through the projects on his website we find almost no information about this build, but he does show off one previous model, as well as a couple of unmanned underwater rover projects.

The pressure hull of the sub is made from corrugated drainage pipe. This isn’t a bad idea as the tube is engineered to be buried in the ground and carry the load of earth on top of it. It’s designed to go down just 30 feet, which explains the lack of half-dome caps on either end; the pressure just isn’t that great at that depth. The buoy floating to his left is his tether to the surface. Fresh air is pumped from here into the sub. He’s also included safety features like a 20-minute air tank in case he gets into a bind, and a quick opening top hatch. That hatch is a hemisphere of clear acrylic which lets him view what’s around him.

You’ll learn more from the two video clips he posted. The Fox 5 news interview includes a shot of one of the messiest work benches we’ve seen. A messy bench is the sign of constant project construction, right?

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Raspberry Pi Helps With 2.4GHz Home Automation

May 30, 2013 by 15 Comments

Wanting to extend the capabilities of the radio frequency devices in his home [Kalle Löfgren] turned a Raspberry Pi into an RF control hub. We’ve seen some of his home automation work in the past. In his media room he built a universal remote base station which used the same RF board as in this project. The main difference is that before he went with an AVR microcontroller and this time he’s upgrade to a Raspberry Pi board.

The RPi brings a lot more to the table. Notably, the scripting (whose output is shown above) and networking features. His radio board is an nRF24L01 which he talks to via the SPI protocol. The Raspberry Pi has no problem talking to SPI devices through its GPIO header. [Kalle] just needed to do a bit of setup to configure the pin modes.

A Python script lets him sent commands using his keyboard, but this can also be automated. Combine that with the TCP server script he wrote and it opens up the a wide range of configurations to switch or talk to any device operating on the 2.4 GHz band.

Giving The Nexus 4 A Serial Port

May 30, 2013 by 28 Comments

Having a serial port on any Linux box is always useful, but with the tiny computers we’re carrying around in our pockets now, that isn’t always an option. Some of the more advanced phones out there break out a UART on their USB OTG port, but the designers of the Nexus 4 decided to do things differently. They chose to put the Nexus 4’s serial port on the mic and headphone input, and [Ryan] and [Josh] figured out how to access this port.

Basically, the Nexus 4 has a tiny bit of circuitry attached to the microphone input. If the Nexus detects more than 2.8 Volts on the mic, it switches over to a hardware UART, allowing everything from an Arduino to an old dumb terminal to access the port.

The guys used a USB to serial FTDI board wired up to a 3.5 mm jack with a few resistors to enable the hardware UART on their phone. With a small enclosure, they had a reasonably inexpensive way to enable a hardware serial port on a mobile device with GPS, cellular, a camera, and a whole bunch of other sensors that any portable project would love.

EDIT: An anonymous little bird told us this: “You should add a note to the Nexus 4 serial cable post that TX and RX need to be 1.8V.  If you use 3.3V USB cables, you will likely eventually fry something.  FTDI makes 1.8V IO cables that work – you just need to make the trigger voltage for the mic line.” Take that for what you will.

Human Asteroids Makes You A Vector Triangle Ship

May 30, 2013 by 22 Comments

asteroids

In 1979, [Nolan Bushnell] released Asteroids to the world. Now, he’s playing the game again, only this time with the help of a laser projector and a Kinect that turns anyone sitting on a stool – in this case [Nolan] himself – into everyone’s favorite vector spaceship. It’s a project for Steam Carnival, a project by [Brent Bushnell] and [Eric Gradman] that hopes to bring a modern electronic carnival to your town.

The reimagined Asteroids game was created with a laser projector to display the asteroids and ship on a floor. A Kinect tracks the user sitting and rolling on a stool while a smart phone is the triangular spaceship’s ‘fire’ button. The game is played in a 150 square foot arena, and is able to put anyone behind the cockpit of an asteroid mining triangle.

[Brent] and [Eric] hope to bring their steam carnival to LA and San Francisco next spring, but if they exceed their funding goals, they might be convinced to bring their show east of the Mississippi. We’d love to try it out by hiding behind the score like the original Asteroids and wasting several hours.

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HP16500B Logic Analyzer Controlled With RS-232 And More

May 30, 2013 by 15 Comments

hp16500b-logic-analyzer

We’re pretty spoiled these days in that hobby electronics has made a lot of cool tools available on a budget. It’s hard to think of a better example than a logic analyzer, which you can get for a day or two of pay. Consumer-level devices just didn’t exist until a few years ago. [Jouko S] has this HP16500B industrial grade logic analyzer in his shop. It’s from the early 1990’s and it’s got a ton of features. Grabbing a still functional yet super-old model used to be the only way for hobbyists. But one thing you won’t find on it is the ability to connect it to your USB port to get screen captures. Younger readers might not recognize the slot at the top for magnetic media called a floppy disk which is the in-built way of recording your sessions. He set out to find an easier way to get color screen captures and ended up adding RS-232 control to the old hardware.

There is a 25-pin port on the back of the old hulk. But it is a female connector and he didn’t have the adapters on hand to make it work with his serial-to-USB converter. During development he used a breadboard and solder-tail connector to patch into the necessary signals. This was all hooked up to a Raspberry Pi which he planned to dedicate to the system. It worked, and he was able to use an interactive terminal for the rest of his sleuthing. With much trial and error he figured out the commands, and wrote some Python code for the Pi side of the equation. He can now pull color screenshots with ease thanks to the utilities available in the Python Imaging Module.

Programming A Through-hole ARM Microcontroller

May 29, 2013 by 32 Comments

NXP

The age of ARM microcontrollers for the electronics hobbyist is upon us, and luckily there are a few breadboard-friendly microcontrollers available in a DIP package. One of these chips is NXP’s LPC810M021FN8 – a tiny little 8-pin DIP with 4 kB of Flash, 1 kB of SRAM, and has a clock fast enough for some really cool stuff. [Joao] needed a way to program one of these microcontrollers and came up with an easy method using only a USB/UART adapter.

The key to this build is the fact the LPC810 doesn’t need any additional components to operate; the internal oscillator means the chip will run at 30 MHz with only a power and ground attached. To program the chip, [Joao] attached the Tx and Rx lines of the chip to a USB/UART adapter (at 3.3 V, of course), and uploaded some code with Flashmagic.

We’ve seen these DIP-sized ARM chips before, but [Joao]’s method of using off-the-shelf tools to write a blinking LED program means it’s a piece of cake to start working with these very cool and very powerful microcontrollers.