April Fools’ project teaches coworkers not to touch your stuff

April 2, 2013 By 38 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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Filed Under: Holiday Hacks Tagged With: , , ,

Building a vehicle parking camera

April 2, 2013 By 12 Comments

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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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Filed Under: Raspberry Pi Tagged With: , , , , ,

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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Filed Under: cnc hacks Tagged With: , , ,

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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Filed Under: how-to Tagged With: , , ,

Hackerspace tour: Arch Reactor in St. Louis Missouri

April 2, 2013 By 8 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.

Filed Under: news

Cooling a photomultiplier tube

April 2, 2013 By 25 Comments

photomultiplier-tube-cooling-rig

A photomultiplier tube is a device used to measure very low levels of light. It’s a common tool of particle physics when trying to detect just a few photons. It turns out that running a tube at room temperature will not provide the best results. To improve the accuracy and sensitivity of his equipment [David Prutchi] built this thermoelectric photomultiplier tube cooling rig.

You can’t actually see the tube in this image but it looks similar to a vacuum tube or Nixie tube. The difference being that the components inside the glass dome make up the detector instead of an amplifier or filament display. To make a physical interface with the glass [David] wrapped it in magnetic shielding and finished with a layer of aluminum foil tape. This cylinder was then snugly fit inside of an aluminum heat sync. two Peltier coolers were attached to the outside of the heat sync, using Arctic Silver thermal compound to help transmit heat. A thermocouple was also added to monitor the temperature of this first stage of cooling. All of this fits into an aluminum enclosure which was filled with expanding spray foam before having a trio of fan-cooled heat syncs attached to it.

Filed Under: tool hacks Tagged With: , , ,

Ask Hackaday: Hacking lingo fails

April 2, 2013 By 114 Comments

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Ah, CSI. What other television show could present digital forensics with such two-bit dialogue?

It’s time once again to put on your hacker hats – a red fedora, we guess – and tell us the worst hacker dialogue you’ve seen in movies or TV. We’ve seen a ton of shows and movies where writers and directors spend zero time doing any sort of research in whatever technology they’d like to show off in the story they’re trying to convey. Usually this results in lines like, “I’ll create a GUI interface using Visual Basic. See if I can track an IP address.” It’s technobabble at its best, and horribly misinformed at its worst.

We’re wondering what you, the readers of Hackaday, think are the worst examples of hacker lingo fails. Anything from, ‘Enhance!’ to the frightening real-life quote, “the Internet is not a big truck. It’s a series of tubes.”

We’ll compile your suggestions in a later post, but I’m betting something from Star Trek: Voyager will make the #1 technobabble/hacking lingo fails. There’s just too much in that show that isn’t internally consistent and doesn’t pay any heed to the laws of (fictional) physics. Warp 10, I’m looking at you. Of course there was the wonderful Habbo reference in last week’s Doctor Who, but I’m betting that was intentional as [Moffat] seems pretty up to speed on the tropes and memes of the Interwebs.

About a month ago, we asked you for your take on the worst hacking scenes ever shown on TV or film. The results made for good viewing, albeit with a surprising absence of Lawnmower Man. Now we want some dialogue to go with these horrendous hacking scenes. So, what say you, Hackaday? What are the worst hacking lingo fails you’ve seen or heard? Please be specific about what movie/TV show you’re referencing. Last time some good stuff probably slipped by because people just said a few words without context assuming we’d know exactly what they were referring to.

Filed Under: Ask Hackaday Tagged With: , , , , ,
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