Month: April 2013

Embedded Web Server Is All About Clever Formatting

April 3, 2013 by 18 Comments

embedded-web-server

Take a look around here and you’ll find all kinds of embedded web servers. This one doesn’t look all that interesting, especially because it’s just a NIC plugged into a development board. But for us the interesting part is in how [Andrew Rossignol] chose to format the webpage assets to best utilize the under-powered server.

The project was spawned as part of a class in Internet Embedded Systems which [Andrew] is taking. The board has an ATmega16 microcontroller and he’s using the ever popular ENC28J60 on that Ethernet adapter board. The TuxGraphics TCP/IP Stack takes care of communications with the network.

One constraint which [Andrew] imposed upon himself was to use just a single response which the available RAM limits to about  700 bytes. Any decent webpage needs to have at least some graphics but that’s tough with the size limit. He managed to display an AVR logo by optimizing an SVG in Inkscape then stripped the rest of the cruft using VIM (explained in the demo after the break). With that piece of Linux-fu in his pocket he set to work streamlining the CSS file. The webpage isn’t just static either. He displays the server up-time and even allows the relays and LEDs on the Olimex board to be controlled.

Despite the limitations of the ATmega family they still seem to do some amazing Internet-connected stuff. Here’s one used as a Minecraft server.

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SenseLamp Automates Rooms By Replacing Light Fixtures

April 2, 2013 by 25 Comments

senselamp

Would you believe that this beautiful light fixture is actually a hacked together home automation project? Okay, so this wire mess is the second of three versions that [Christian] built. It replaces a light fixture in the room, but if you look closely you’ll see that there is a compact fluorescent bulb included in the build. The laser-cut frame acts as a bit of a lamp shade, while providing a place to mount the rest of the hardware.

The final version cleans things up a bit, and adds a footprint for the PIR motion sensor that he forgot to design into this version. The idea is that each lamp monitors motion in the room, switching the light on and off again as necessary. A light-dependent resistor ensures that the bulb is only powered up if the room is dark so as not to waste electricity during the day.

The build includes a sensor package that reports back temperature and humidity data. Communications are provided by a WR703N router rolled into each of the four units installed in his house. With this kind of hardware at his disposal it should be a snap to control every IR remote control device in his house via the network by adding an IR LED and some code to the lamps.

April Fools’ Project Teaches Coworkers Not To Touch Your Stuff

April 2, 2013 by 41 Comments

april-fools-siren-box

Take one look at the sticker on top of this project box and it’s pretty clear you’re not supposed to flip the switch protected by the piece of red plastic. But if your coworkers are anything like [The Timmy’s] there’s at least a few who will stop by and just can’t keep their hands off. He built this to teach those sorts a lesson. Flip the switch and a very loud siren starts blaring. The thing is, the 107db alarm can’t be turned off by the switch, you must have the key for the switch on the side.

The siren is a self-contained unit that just needs a power source between 6V and 15V. This makes the project quite simple, the only part that [The Timmy] really needed to think about was how to build a mechanical SR Latch (set-reset). The solution is to use a mechanical relay. The toggle switch connects the normally open connector to the common terminal to enable the relay. The key switch breaks the relay’s connection to ground, allowing the magnetic switch to open again.

If you need some help understanding how the relay connections work we’ve embedded an unrelated video after the break.

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Building A Vehicle Parking Camera

April 2, 2013 by 12 Comments

rpi-backup-camera

We’re never really sure what to call these things. When we say “back up camera” it sounds distinctly like a redundancy system for when the primary camera fails to work. But it is used for when you move in reverse in an automobile. [Jeremy Blythe] built the distance sensing video system using a Raspberry Pi board as the brain.

The flexibility of Linux and the power of the RPi board ended up making it pretty easy to get everything working together. He’s using a Microsoft Lifecam Cinema HD camera, which connects to one of the USB ports on the board. Just above that you can see the infrared distance sensor which is connected to the RPi’s GPIO header using one of Adafruit’s Pi Cobbler breakout boards. This also facilitates the connection to the 176×220 color LCD screen.

In the video after the break you can see [Jeremy] testing out the system by moving his hand in front of the sensor. Python is used to grab the image from the camera, draw a circle on it, and overlay the distance in centimeters at the bottom. Once his hand is within 30cm the overlay turns red and the work STOP is displayed. Pretty neat!

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CNC Tic Tac Toe

April 2, 2013 by 5 Comments

cnc-tic-tac-toe

This computer controlled physical Tic Tac Toe game is built from parts scavenged from common consumer goods. Specifically, the sled is made up of a combination of printer and DVD drive parts.

The build is delightful, and you can’t move on to the next feature until you watch it play a game in the clip after the break. The game board can move along two axes. It’s obvious from the image above that the printer ink cartridge sled has been reused to let the board move left and right. But the DVD lens sled hidden under the board lets it move forward and back. The piece of protoboard seen on the left is an IR reflectance scanner. The board moves systematically under this sensor. Whenever a black square (placed by the human player) is in play it prevents the IR beam from reflecting back. What you can’t see in this image is the yellow disc dispenser which is just out of the frame. It uses the DVD disc tray motor to place the computer’s pieces. We think this build is just begging to be turned into a Turing Machine demonstration.

If you liked this one we’re sure you’ll also appreciate CNC chess.

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Adafruit Launches Educational Show Aimed At Kids

April 2, 2013 by 25 Comments

adafruit-kids-show

Adafruit Industries just posted the first episode in a new educational series aimed at teaching kids about electronics. The episode is entitled “A is for Ampere” and teaches the basic theory behind electrical current. The subject seems like a common one for A-to-Z themed electrical tutorials. [Jeri Ellsworth] did a similar episode but hers is aimed more at the electronics hobby crowd.

[Limor] and gang (that’s [Collin Cunningham] dressed up as [Andre-Marie Ampere]) seem to be all-in on this project. The episode features ADABOT, the blue puppet which takes on the role of the student in this episode. After demonstrating a mains circuit breaker tripping the episode goes on to discuss electron flow and how current is measured.

We’re all about this type of educational opportunity. The age group at which this series is targeted have never known a day without touchscreens, they should know at least something about how those devices actually work.

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Hackerspace Tour: Arch Reactor In St. Louis Missouri

April 2, 2013 by 10 Comments

Over this last weekend I was lucky enough to find myself in St. Louis, Missouri. Some of my favorite places in the universe are there, the city museum being one that pops into mind most frequently.  I realized I had never toured a hackerspace in St. Louis though!

A quick phone call to Arch Reactor remedied this. Even though it was Easter Sunday, they came down and gave me a tour.  The  space was quite nice with a lounge area, electronics workstations, fabrication tools and a complete wood shop. On top of the hackerspace’s pleasant atmosphere, the building also includes a fun little art-bike group called the Banana Bike Brigade,  and even has a roof-top bar made from reclaimed materials. For those of you who are into cars, in the bike shop there were several nice corvairs and a porsche 911 that appeared to be mid 80s.

If you ever get a chance to stop by, you should definitely try to visit Arch Reactor.