33 Node Beowulf Cluster Built With Raspberry Pi

May 21, 2013 by Mike Szczys 81 Comments

Not only did [Josh Kiepert] build a 33 Node Beowulf Cluster, but he made sure it looks impressive even if you don’t know what it is. That’s thanks to the power distribution PCBs he designed and etched. In addition to injecting power through each of the RPi GPIO headers they host an RGB LED which is illuminated in blue in the images above.

Quite some time ago we saw a 64-node RPi cluster. That one used LEGO pieces as a rack system to hold all of the boards. But [Josh] used stand-offs to create the columns of hardware which are suspended between top and bottom plates made out of acrylic. The only thing that’s unique about each board is the SD card and that’s why each has a label on it that identifies the node. These have been flashed with almost identical images; the host name and IP address are the only thing that changes from one to the next. They’ve been put in order physically so that you can quickly find your way through the rack. But functionally this doesn’t matter… put the card in any RPi and it will automatically identify itself on the network no matter where it’s located in the rack.

Don’t miss the demo video where [Josh] explains the entire setup.

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ATX Raspi Is A Smart Power Source For Raspberry Pi

May 19, 2013 by Mike Szczys 55 Comments

One aspect of the Raspberry Pi that has always challenged us is the power supply. It was a great idea to power the board from a standard micro-USB port because economy of scale makes phone chargers (even in the 1A range necessary for stable operation of the RPi) cheap and easy to acquire. The thing we miss is the ability to power the device on and off using the built-in hardware. The quandary has given rise to many different solutions, and the ATX Raspbi smart PSU is one of the better ones we’ve come across. It’s a nicely packaged take on the PIC-based version we saw earlier in the year.

The device is a small PCB that acts bridge between the micro-USB power supply and the RPi board. It offers several breakout headers, one of which is used for a power button. The button is monitored by a microcontroller that switches the on-board relay accordingly. But it won’t just kill the power when you want to shut down. It first signals one of the RPi GPIO pins, causing the OS to execute a shutdown script. It then monitors the RPi for the shutdown tasks to finish before cutting the power.

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Hackaday Links: Sunday, May 12th, 2013

May 12, 2013 by Mike Szczys 23 Comments

[Johnathan Crawford] isn’t bashful about tearing the insides of his truck apart. He’s built his own remote starter using a Raspberry Pi.

We vaguely remember hearing about a startup that planned to deliver tacos using quadcopters instead of people. We assume that company was a bust but here’s the concept in action at the 2013 RoboGames [thanks Don].

On the topic of food: pizza and joysticks… do they go together? Perhaps. Here’s a joystick made out of an empty pizza box (note the remains of grease stains inside).

[Jonathan] brings to our attention the problem of running out of fingers to press all the buttons on your Monome at just the right moment. No worries, just add some solenoids to act as extra fingers.

Apparently some Samsung cameras (NX20, NX210 and NX1000) can use their USB port as a shutter release. The trick is finding the right resistor values for the ID pin [thanks Janne].

Plagued with a tablet dock that wasn’t weighty enough to prevent the device from tipping over [John] filled base with lead to keep the thing upright.

[Helmut’s] bathroom had no windows. He faked one using an Arduino and an RGB led.

And finally, as a reward for all the readers that made it to the bottom of the article, here’s a gem of a project. [Charlie] was inspired by the recent logic combo lock post to send in his own plans for a lock he made years ago. Unfortunately he can’t find the pictures from the build but the theory behind it is quite engaging.

Raspberry Pi Housed Inside A Computer Monitor

May 9, 2013 by Mike Szczys 22 Comments

rpi-inside-a-computer-monitor

Behold, something we’ve always wanted. [Matthieu] mounted his Raspberry Pi board inside of a computer monitor. His work makes for the cheapest smart-TV modification we can possibly think of.

The image above shows the monitor’s driver board on the left, with the Raspberry Pi mounted on the back plastic cover. [Matthieu] used a short HDMI cable to connect the two. The HDMI connector plugs into the RPi directly. The other end has been cut off and the wires soldered to the DVI pins on the monitor’s PCB. This is not a problem since HDMI and DVI use electrically identical protocols. The one thing missing is audio. But if you were pulling off the same hack with a device that had HDMI (like a television) it would just be a matter of also soldering in the audio connections. While he had his iron hot he also connected a 5V source from the monitor board to the RPi. He completes his hack by cutting a slot in the monitor case to allow access to the SD card.

We’ve long wanted an XBMC computer we could velcro to the back of the TV and the RPi turned out to be just the thing. Now we’ve got to consider cracking open the TV to replicate this internalization hack!

Sump Pump Alarm Sends Text Message As Water Rises

April 30, 2013 by Mike Szczys 45 Comments

sump-pump-monitor

We’ve got some friends who have two sump pumps. One is a backup and sounds an alarm when it is switched on. But this only works as long as they’re home to hear it. [Felix Rusu] came up with a solution what will text him if the sump pump fails. This way he can head home, or call someone to check in on the problem if he’s away.

We saw a pretty complicated monitoring system back in January. This one uses a single ultrasonic rangefinder which we think is much simpler. It’s accurate to about 1cm and is simple to use — it’s very popular with the hobby electronics crowd which helps with price and availability of sample code. We hem and haw about the use of a Raspberry Pi board with the project. On the one hand it’s a cheap way to get the sensor on the network and provides the infrastructure you need to send any number of alerts. On the other hand, it’s a lot of power for this particular application. But we figure it can be extended to monitor other utilities in [Felix’s] home, like a sensor to alert him of a leaking water heater. And we think everyone can argue that a monitor like this is well worth the time and effort he spent to develop it.

Old LED Marquee Turned Embedded Video Player

April 26, 2013 by Mike Szczys 12 Comments

driving-led-marquee-with-rpi

[Sprite_TM] is was sent an old LED Marquee by an anonymous fan of his hacking projects. The display isn’t full color, but it’s large — 224 by 48 pixels — and he figured he could render some okay images with the bi-color diodes. In the end, he replaced the controller and turned it into a video player.

The original system work well enough, but the 100 MHz 486 industrial style PC that drove the display seems a little comical these days. After giving it a spin and testing out how it drives the display [Sprite] hooked up an FTDI chip and managed to get it playing video from his computer. Above you can see part of the opening sequence of The Simpsons.

Now that he had learned its secrets he set out to give it an embedded controller. His first attempt was with a Carambola board which he’s worked with before. That proved to be a little slow for all the pixel data he was pushing so he upgraded to a Raspberry Pi and never looked back. You can see the demo video after the jump.

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Hackerspace Security System Brings RFID, Video Feedback, And Automatic Doors

April 17, 2013 by Mike Szczys 38 Comments

rfid-hackerspace-door-lock

[Will] has been hard at work on a replacement system for his Hackerspace’s RFID door lock. The original is now several years old and he’s decided to upgrade to a much more powerful processor, adding some bells and whistles along the way.

The control box seen above is the exterior component of the system. It’s a telephone service box like you’d find on the back of most houses in the US. They had a few of these lying around and they are a perfect choice because… well… they’re meant to be locking enclosures that brave the elements. [Will] made the jump from an Arduino which has run the locks for the last three years to a Raspberry Pi board. This gives him a lot of extra power to work with and he took advantage of that by adding a vehicle backup LCD screen for visual feedback. You can see it giving the ‘Access Granted’ message he used during testing but the demo video after the break shows that they plan to do some image scripting to display a head shot of the RFID tag owner whenever a tag is read.

There are several other features included as well. The system Tweets whenever a tag is read, helping the members keep tabs on who is hanging out at the space right now. It also patches into a sliding door which one of the members automated using a garage door opener motor.

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