Link spam your friends with printed QR codes

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While [Oryx] is down with social media like Facebook and Twitter, there are times when he wants to share things with people he is hanging out with in the real world. Sure, he could always email his friends links to the latest video of a cat doing something totally hilarious, but he wanted something a bit more tangible.

He had a small thermal printer from SparkFun kicking around, and thought it would be the ideal medium for sharing things with others. He sat down and put together a bit of code that allows him to interface the printer with his computer, generating QR codes from his web browser with the simple click of a button. Now, when he wants to pass something along to a friend, he can quickly print out a label bearing both a QR code and URL for easy access later on.

All in all it’s an interesting idea, though we would be curious to see what would happen if we handed our non-techie friends a printed QR code.

Character LCD spectrum analyzer made simple with a dedicated IC

[El Artis] just finished building an audio spectrum analyzer that uses a character LCD. The uses an Arduino to drive the display, but unlike other meters that use the microcontroller for analysis, [El Artis] is using a discrete IC for that task.

This project uses the MSGEQ7 graphic equilizer display filter chip to grab frequency data from the audio source. The chip connects to your microcontroller of choice using two digital pins and one analog pin. [El Artis] points us to [J Skoba's] post about how to use it with an Arduino, then adds his own custom character routines for an HD44780 display. You’ll notice that there are sixteen bars in the image above, which conflicts with the 7 outputs the chip offers. [El Artis] averages neighboring values in order to add the extra outputs.

Don’t miss the demo video after the break. If you’re looking to use this part in one of your projects, we noticed they’re a little hard to find (octopart doesn’t return any suppliers) but SparkFun has them.

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Full-color eBook reader needs only 8-bits of muscle

[Rossum's] still coming up with great ways to use his microtouch hardware. This time, he’s taken his inspiration from Amazon’s announcement that a full-color eBook reader (and movie player) is on the way. Judging from the video after the break, his fully functional reader is a big win for the device.

You’re probably familiar with the hardware, an ATmega644-based board connected to a touch sensitive LCD screen. You can make your own or buy one pre-assembled (but currently out-of-stock). The board has a microSD card slot making it quite easy to add books to the device. At the start of the project [Rossum] thought he might be able to read ePub files directly, but the embedded images, and unzip function needed to open the package file is a bit too much for the 8-bit processor’s restrictions. One simple step does the trick. A helper script can be used to format the files before transferring them to the device. This does the unzipping, scales the images, and repaginates the text into a format friendly for the display size.

Now if we only had a nice little case to house the hardware we’d be in business.

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Ultrasonic rangefinder as scanning radar

Ultrasonic rangfinders are a cheap and easy way to gather obstacle avoidance data. When added to a servo motor they form something of a scanning radar for near-proximity objects.

In this implementation, [Rui Cabral] is driving the servo, and collecting data from the sensor using a PIC 18F4520. The servo rotates 180 degreees, taking sensor measurements in increments of nine degrees. If it discovers obstacles, the distance and orientation are recorded. Feedback is displayed on a 20-LED bar graph display which shows a moving LED to track the sensor orientation, with LEDs remaining lit whenever an object is found. Right now the obstacle data is pushed over a serial connection with a PC, but could easily be injected into navigation logic for a robot in order to triangulate a path around the obstruction. You can see [Rui's] project in action after the break.

We looked in on the same concept with a different display technique a couple of years back. That hack used an Arduino and Processing to map sensor data with a traditional green sweep display.

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How to build a 23″ Android tablet

If you’re looking to build a really big Android tablet the trick is not to start from scratch. [Peter] pulled off a 23″ Android Tablet hack using a collection of easily acquired parts, leaving the hard work up to hardware that was designed to do it.

He didn’t really build a tablet, as much as he built a big touch-screen add-on for one. He already had a couple of inexpensive tablets on hand to play around with. One of them has an HDMI out port, which let him easily push the display onto a 23″ monitor. He knew the tablet was a 4-wire resistive touchscreen, but he didn’t know if other touchscreens with the same number of connectors and be directly swapped and still work. To test this, he cracked open a second tablet device and connected its touchscreen to the first one’s hardware. When he was met with success it was time to source a couple of 23″ touchscreen overlays to test with the external monitor. As you can see in the clip after the break, it works like a charm!

[Peter] was inspired to write about his experiences after seeing the 23″ Android tablet video in our recent links post.

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Electric mountain board with glove control

Last summer, we saw [Andres Guzman]‘s electric mountain board tearing around the University of Illinois campus. He’s back again, only this time the board isn’t controlled with a PlayStation controller. [Andres] built a wireless glove to control his mountain board.

An Arduino and power supply is mounted to the glove. A 2.4GHz transceiver serves as the comm link between the glove and board. The speed control is handled by this flex sensor from Sparkfun. With the flex sensor held between the middle and ring fingers, all [Andres] needs to do to apply power is slightly bend his fingers.

There’s also a number of safety features built into the board. To enable power to the boards motor, there’s a dead man switch on the glove underneath the thumb. If [Andres] were to take a nasty spill, he would release the switch and the board would come to a stop. [Andres] also made sure the board would shut down if the wireless link was interrupted. The build seems pretty safe, even if he is tearing around his campus in the video below.

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Animated X-mas sign

Sure, it may be two and a half months until Christmas. That doesn’t mean we can’t start building a few Christmas decorations. Last year, [RB] over at Embedded Lab made an animated Christmas sign using a simple microcontroller setup. This year, [RB] is adding a blinking LED border and doing the entire project with 74xx ICs.

The letters for this year’s sign were recycled from last years’. This time, however, two strings of 12 LEDs are used for the blinking border. The blinking circuitry uses a 74hc14 Schmitt trigger to provide the clock. A pair of 74hc595 shift registers turn each letter on one at a time. The speed is controlled with a small trim pot.

Using ICs to drive a series of lights in a pattern isn’t a new thing – you’d be hard pressed to not find a similar setup in the blinking panels of sci-fi shows of the 60s and 70s. Of course this sign doesn’t compare with what can be done with a microprocessor a lot of patience, it’s still a very nice build. Check out the video after the break to see the X-mas sign in action.

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