Play Hide-and-go-seek With Infrared LEDs

February 6, 2012 by Brian Benchoff 16 Comments

Although we’re sure they exist, we wouldn’t want to meet anybody that can’t look back fondly on the halcyon days of youth that included playing hide-and-go-seek. Some kids never grow up and continue the tradition with geocaching or orienteering, but that sense of limitless discovery wanes over time. [Kurt] came up with a small scavenger hunt beacon that brings back the unending wonder that accompanies the unknown.

The beacon is just a simple ATtiny13 that flashes a message with an invisible IR LED. To receive the messages, [Kurt] made a scavenger decoder shield for an Arduino. The decoder includes a phototransistor and a 20×4 LCD display. All [Kurt] needs to do is hold the decoder up to the beacon for the text in the firmware of the ATtiny to be displayed. The beacon is only one inch square and powered by a watch battery, so it can be hidden anywhere.

[Kurt] suggests that the text of one beacon should provide the clue to the next. We’re thinking this is just a great excuse for a walk in the park. You can check out [Kurt]’s IR decoder getting data from a beacon after the break.

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Robotic Etch-a-Sketch Draws Grayscale Images

February 6, 2012 by Kevin Dady 14 Comments

[Patrick] decided to make a computer controlled etch-a-sketch. While the idea is not that new, there is always a different way to accomplish a goal. An Arduino is used to control a pair of stepper motors which were sourced for pretty cheap, and even came with their own driver. Next a stand was mocked up using foam board, which helps determine where all the parts should live.

Next was a way to attach the steppers to the knobs, gears would be used and a collet meant for model airplanes was sourced to make the mechanical connection between gear and shaft. With everything set in place via foam board and paper printouts, it is off to get some thin plywood. The plywood is sent though a laser cutter creating most of the stand and gears. Now its all software, a program was whipped up for OSX which converts low res pictures into squiggly lines perfect for the etch-a-sketch to draw on its screen.

The results are quite impressive, join us after the break for a quick video.

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Office Game Show Buzzer Keeps Things Fair And Square

February 3, 2012 by Mike Nathan 15 Comments

The sales team in [Chuck’s] office is a pretty competitive bunch as you might expect, and they decided that they wanted a system which would allow them to challenge one another during their weekly meetings. The competition involves answering questions posed by their manager, but hand raising only works for so long – they needed a definitive way to tell who “buzzed in” to answer a question first.

Since [Chuck] only had a short bit of time and a tiny budget to work on, he opted to find the easiest solution to the problem, which was an Arduino-based game show buzzer system. The game display is built from an Arduino, some LEDs and an Altoids tin, while the buzzer pushbuttons were salvaged from an old radio broadcast console.

Now, when a question is posed, the salesman can buzz in to answer, knowing that only the quickest person’s button click will be registered. When it’s time for another question, the host simply clicks his buzzer to reset the console.

While it’s not quite as fancy as this game buzzer system we featured a while back, [Chuck] says it does the job perfectly and was cheap to boot.

Continue reading to see a short video of the office game buzzer system in action.

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Rapid Fire, Remote Controlled Ping Pong Ball Turret

February 2, 2012 by Mike Nathan 15 Comments

remote-ping-pong-ball-turret

[Andrew] and his brother had some time (and a lot of ping pong balls) on their hands, so they decided to have some fun and built a remote-controlled ping pong ball turret.

Arduino aside, the turret is cheap and easy to build as [Andrew’s] writeup explains. The firing mechanism was constructed using a pair of foam wheels and motors, which is used to launch the ping pong balls much like a baseball pitching machine. The balls are stored above the wheels in a cardboard tube and released by a mechanical flap when triggered.

When [Andrew] is ready to release the turret’s payload, he sends a command to his computer over VNC, which relays the command to the Arduino over a serial connection, triggering the flap. While the control scheme could certainly benefit from direct, wireless phone-to-Arduino communications, it seems to work well enough for [Andrew’s] needs.

Check out the video dramatization below to see [Andrew] “surprise” his brother with a hail of ping pong balls after the jump.

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Reading Diodes To Create A Thermal Imaging System

February 1, 2012 by Mike Szczys 35 Comments

[Udo Klein] was working with some 1N4148 transistors and was interested in the specs relating to their performance at different temperatures. The forward voltage actually changes quite a bit depending on temperature and wondered if this could be reliably measured. He hacked his own LED shield for the Arduino to use as a 1×20 thermal imaging system.

The screenshot above is mapping the voltage measurements from a row of diodes (see the video after the break to get the full picture). He’s holding an ice pack over the row of diodes and observing the change. The on-screen display is facilitated by a Python script which is pulling data from the Arduino. Since there aren’t enough analog inputs to read all twenty diodes separately they have been multiplexed. Four I/O pins each enable five of the diodes, readings are taken with five analog inputs before moving on to the next set.

What can this be used for? That is precisely the wrong question… sometimes you’ve just got to go where your curiosity takes you. Continue reading “Reading Diodes To Create A Thermal Imaging System” →

Weapon Of Mass Graffiti

January 31, 2012 by Mike Szczys 48 Comments

What uses a fire extinguisher, a bike pump, and provides hours of probation, community service, and possibly jail time? If you said an automatic graffiti writer you’re correct! [Olivier van Herpt] calls this little job the Time Writer. We call it defacing property… but tomato, tomahto.

Details are a bit scarce, but you get a fine overview of the system from the video after the break. [Olivier] tagged the post as Arduino; it’s obviously running the dot matrix printer made up of seven solenoid valves on a metal rod. These are fed ink via a tube connected to a fire extinguisher which serves as the reservoir. The bike pump is used to pressurize the enclosure so that a pump isn’t necessary when out and about.

Obviously you shouldn’t try this at home, but let’s talk about possible improvements as an academic exercise. First off the mix of the ink/paint needs to be reigned in to get rid of the dripping. We’d also like to see the inclusion of some proper spray can nozzles to tidy up the results. That, paired with an IMU board should be able to smooth out the printed designs.

This might make an interesting add-on to that rainbow graffiti writer.

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Telegraph Key Makes For A Fantastic Twitter Input

January 31, 2012 by Brian Benchoff 21 Comments

In the interests of interface archaeology, [Martin] sent in the Tworse Key, a telegraph key that posts to Twitter using Morse code. It’s a fantastic build that nearly looks like something out of the 1900s.

We’ve seen a ton of Morse keyboards over the years, but never one so well-engineered for a single purpose. The guts and brains of the Tworse Key is an Arduino Ethernet that connect to Twitter over the API. The Tworse Key automagically posts all the Morse messages to Twitter. The Tworse Key may have fallen off the table a few times in the past 24 hours, but we do see a few purposeful messages like ‘sos’ and [Bell]’s preferred telephone salutation.

We could say that nobody uses straight telegraph keys anymore, but outside a few hardcore CW HAM radio guys nobody uses Morse anymore. This isn’t meant to be used as an everyday input device, though. It’s more of an exercise in interface archaeology. That being said, an iambic key would be a far more ergonomic solution. Check out the video of the Tworse Key after the break.

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