Wake On LAN With A Dev Board

May 19, 2014 by Brian Benchoff 23 Comments

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At home, [Daniel] has an extremely powerful dual quad-core Xeon system with ECC RAM that he uses for heavy lifting tasks – compiling, CUDA processing, and actual computing. Of course the electric bill for running this box all the time would be crazy, so Wake on LAN it is. There’s only one problem: for some reason, the BIOS doesn’t have Wake on LAN. The solution, of course, was a microcontroller system that would listen for the magic WoL packet and turn the computer on when it was received. This project eventually turned into a great case mod with an integrated LCD that powers the computer up over Ethernet, shows the current running processes, CPU and memory usage, and is an excellent use of a TI dev board.

The dev board in question is a TI Sitara AM355x starter kit that runs Linux, has two Ethernet ports and a touch sensitive LCD, and more than enough power to handle something as simple as a system monitor. To power on his monster computer from the dev board, [Daniel] is using a LED on the board, an inverter, a ULN2003 driver chip, and a relay connected to the computer’s power button. It’s not exactly a masterpiece of craftsmanship, but the dev board looks good mounted in the case, and from the videos below, it’s a great way to get system information embedded right into a computer case.

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Catching Drops Of Water With LEDs

May 19, 2014 by James Hobson 21 Comments

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Ever wonder how they capture seemingly perfectly timed photographs of water droplets? Most of the time it’s done by using an optointerrupter whereby it detects the droplet falling and then triggers a light source a few milliseconds later with your camera ready and waiting.

This is typically done with something called an air gap flash, which is usually rather expensive or difficult to make, but [Michal’s] figured out another easier way suitable for some applications — using an array of LEDs to illuminate the scene.

He’s got a IR diode, a photo-resistor, a few spacers, some plastic and a bunch of hot glue to make up his optointerrupter. When the droplet passes through the IR beam it breaks the signal from the photo-resistor which then triggers his ATmega48P. It waits 80 milliseconds (he timed it out) and then turns on the LEDs for approximately 50 microseconds. Meanwhile his camera is watching the whole event with a shutter-speed of a few seconds.

This works because LEDs have rise and fall times that are much shorter than a traditional camera flash — normal flashes light up for 1-2 milliseconds, as opposed to this 50 microsecond LED flash. Just take a look at some of the pictures!

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Arc Attack Shows Off Tesla Backpack Which Is Certainly Not A Weapon

May 19, 2014 by Mike Szczys 23 Comments

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[Steve Ward] showed us his Tesla coil project which looks very much like a video game weapon. The hand-crafted masterpiece really packs a punch, able to throw off fat white arcs or a bit less threatening bolts of purple plasma. The video above is noisy and dark, but the look at the electronics in the backpack (holy huge capacitors batman!) and the quick functional demo are both more than worth posting. Unfortunately we didn’t get audio of the gun in action so you’ll have to image those sound effects.

The rig is powered by a 5Ah lithium battery which provides the 60V that gets boosted to 400V. The giant caps already mentioned store about 2k Joules (we love it how [Steve] can’t say that 2,000 Joule figure without beaming with joy). This project is the most advanced version of the prototype we saw a few years ago in Kansas. If you want to see more of what these guys are up to head over to their homepage.

Mikey, The Robot That Charges Itself

May 19, 2014 by Adam Fabio 21 Comments

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Mikey is [Mike’s] autonomous robot. Like any good father, he’s given the robot his name. Mikey is an Arduino based robot, which uses a Pixy camera for vision.

[Mike] started with a common 4WD robot platform. He added an Arduino Uno, a motor controller, and a Pixy. The Pixy sends directions to the Arduino via a serial link. Mikey’s original task was driving around and finding frogs on the floor. Since then, [Mike] has found a higher calling for Mikey: self charging.

One of the most basic features of life is eating. In the case of autonomous robots, that means self charging. [Mike] gave Mikey the ability to self charge by training the Pixy to detect a green square. The green square identifies Mikey’s charging station. Probes mounted on 3D printed brackets hold the positive leads while springs on the base of the station make contact with conductive tape on Mikey’s belly. Once the circuit is complete, Mike stops moving and starts charging.

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Youthful Destruction At Maker Faire

May 19, 2014 by Mike Szczys 28 Comments

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Who didn’t get in trouble for taking things apart as a kid? The TakeItApart booth at the 2014 Maker Faire was among my favorite. It let anyone (especially the kids) grab a piece of electronics headed for recycling and crack it open just to see what is inside. The good news being that you didn’t need to be able to put it back together again since it’s just going to be ground up for its constituent materials anyway.

There’s something cathartic about watching a 7-year-old stabbing at a Walkman radio with a slotted screwdriver (those plastic cases are more robust than you might think). I asked if anyone had managed to slice open their hand back-to-the-future style in the process and thankfully the answer was no. But there was at least one instance of “free daycare” where the parents wandered off — there are plenty of distractions at MF — much to the chagrin of their progeny.

Seeing this made me think of this recent interview with [Bunnie Huang] in which he mentions taking chips out of their sockets on an Apple II when he was a kid. He would pull them and replace them backwards to see what effect it would have. Ha! If you have a similar childhood experience to share we’d love to hear about it in the comments. If you just want to see the guts of a bunch of stuff head of to TakeItApart.

An Experiment To Test Radioactive Decay Varying Over Time

May 19, 2014 by Brian Benchoff 64 Comments

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Here’s a hypothesis for you: radioactive decay varies over time, possibly with a yearly cycle. [Panteltje] decided to test this hypothesis, and so far has two year’s worth of data to comb over.

Radioactive decay can be easily detected with a photomultiplier tube, but these tubes are sensitive to magnetic fields and cosmic rays that would easily fly through just about any shielding [Pantelje] could come up with. Instead, the radiation in this setup is detected with simple photo detectors, pressed right up against a tritium-filled glass ampoule, a somewhat common lighting solution for fishing lures, watch faces, and compasses.

The experimental setup records the photo detectors, a temperature sensor, and a voltage reference, recording all the data to an EEPROM once an hour. All the important electronics are stuffed into a heatsinked, insulated, light-proof box, while the control electronics reside on a larger board with battery backup, alarm, indicator LEDs, and an RS232 connection.

After one year, [Pantelje] recorded the data and reset the experiment for another year. There are now two years worth of data available, ready for anyone to analyze. Of course, evidence that radioactive decay changes over the course of a few years would turn just about every scientific discipline on its head, so at the very least [Panteltje] has a great record of the output of tritium lights against the expected half-life.

Pokemon Artificial Intelligence Is Smarter Than You

May 19, 2014 by Rich Bremer 12 Comments

Who out there hasn’t angrily thrown a game controller across the room after continually getting killed by some stupid game-controlled villain? That is such a bummer! You probably wished there was some way to ‘just get past that point’. To take a step in that direction, [Ben] created an Artificial Intelligence program that will win at Pokemon Blue for Game Boy Advance.

The game is run in a Game Boy Advance emulator known as Visual Boy Tracer, which itself is a modified version of the most common GBA emulator, Visual Boy Advance. What sets Visual Boy Advance apart from the rest is that it has a memory dump feature which allows the user to send both the RAM and the ROM out of the emulator. The RAM holds all values currently needed by the emulator, this includes everything from text arrow flash times to details about currently battling Pokemon to the players position in the currently loaded map. The memory dump feature is key to allow the AI to understand what is happening in the game.

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