Ever wonder where cool interactive museum exhibits come from?

[Victor’s] girlfriend works at a museum and enlisted his expertise in designing an interactive detective game for kids visiting the museum. The vision was for the kids to discover phone numbers that they could call for clues. Originally he planned to display the clues on a character LCD, but obviously it’s much neater to hear the clues in the handset of the phone.

Quickly switching gears, [Victor] dropped the ATtiny2313 and started over with an Xmega chip — in fact, it was our recent Xmega post that inspired him to document his project. The microcontroller is responsible for a lot of goings-on. It scans the key matrix for inputs, simulates the DTMF touch tones, reads audio files from a FAT file system on an SD card, and plays them back over the hand set’s speaker. Since most of the hardware is already built into the phones, it was not hard to fit his add-ons inside the case. A simple audio amplifier circuit joins the microcontroller, which is patched into the rows and columns of the keyboard. Take a gander at the video after the break to see the device in action.

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Bit banging VGA from an SD card slot

If you’ve got some favorite electronic device that includes an SD card slot but doesn’t have a video out port you may be able to push VGA signals through the card reader conductors. That’s exactly what’s going on above with the Ben NanoNote, a sub-$100 Linux device which we’ve seen using its SD card slot as general I/O before.

The hardware to capture the signals includes a breakout board for the card slot. Free-formed on the other end of that connector card is a gaggle of resistor which handle level conversion for the VGA color signals, with a VGA cable taking it from there to the monitor. The software that makes this happen is a dirty hack, blocking all other functions while it displays a still image. But we’re sure that it can be cleaned up somewhat. Just don’t hold out hopes for full-motion video, this little guy just doesn’t have it in him.

[via Dangerous Prototypes via Slashdot]

Single-chip digital audio player

[Dmitry Gr.] built a simple circuit to playback digital audio. At the center you can see an 8-pin PIC 12F1840 microcontroller. It’s pulling audio data from a microSD card which is read through a full-sized SD card adapter to which he soldered jumper wires for all of the necessary connections. There is one additional semiconductor, a FET which is used to drive the speaker seen to the left. Unregulated power is provided by a pair of AA batteries (four are seen in the picture above but only two are actually connected to the circuit). He’s planning to post his code package soon, but for now you’ll have to be satisfied with a couple of demo videos and a schematic. Both videos are embedded after the break, and we’ve also included a screenshot of the schematic which is shown in the second video.

This is very similar to the 1-Bit Symphony CD we saw almost a year ago in a links post. That one used a jewel case instead of the protoboard seen here, and had a headphone jack instead of the speaker.

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SD activity indicator for Wii

[DeadlyFoez] wanted to know when the SD card in his Nintendo Wii was in use. He built and indicator LED using a PICAXE 08M and added it next to the SD slot. He uses one pin of the microcontroller to monitor the voltage on one pin of the SD card slot. That pin has a specific value when the card is idle, which rises when it’s in use. He didn’t share the details of which pin he’s sampling, or what the magic number from his source code actually represents. But the concept should be enough of a start if you want to do this one yourself. Watch it go blink-ity-blink in the clip after the break.

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MP3 player barely larger than an SD card

If your board fabrication and soldering skills are up to it, you can make your own tiny MP3 player. This rendition is just about half again as large as a standard SD card, whose slot is on the bottom of the board seen above. The heavy lifting is taken care of by a VS1011 MP3 decoder which also has its own stereo headphone driver on-chip. There’s no display and it seems that most of the 4k of program memory on the PIC 18LF88 is being used. Too bad, we’d love to take this to the next level, attaching it to the head unit in a car and spoofing the communications as if this were a CD changer.

[via Hacked Gadgets]

Chumby webserver using upgraded internal storage

The Chumby One has an internal SD card offering a fair amount of storage. [Kenneth Finnegan’s] came with a 1 GB card that had about 500 MB left over which he filled with a collection of MP3s. But he wanted to do more and so installed a pre-compiled version of lighttpd to act as a web server. The problem is that this binary requires a thumb drive to be plugged in because it maps the storage directory to the mounted USB folder. He wasn’t happy with that so he upgraded the internal SD card and rolled his own webserver to run from the internal SD card.

The upgrade involved going from a 1 GB to an 8 GB microSD card. In order to run the webserver internally he needed to recompile lighttpd to use a different root directory. This meant setting up an ARM cross-compiler and eventually finding a new place for the start up script. The location change for the ‘lighty’ directory leaves us wondering if a symlink couldn’t have solve the problem without recompilation. But we don’t have the hardware on hand to try this out ourselves.

But if you want to give it a shot, check out [Bunnie’s] post about Chumby-based hardware. Looks like you can head out to the big-box store and have one in hand without shelling out too many clams.

RC controlled camera takes intimate video of rodents

[Leor] wanted to take some video of the wildlife in his yard, like this chipmunk or some hummingbirds, but every time he tried to get close it scared them away. His solution was to rig up a cheap video recorder to be radio controlled (PDF). The donor camera was a cheap SD card based eBay purchase that takes 720×480 video. [Leor] removed the SMD switches from the recorder’s PCB and wired up a 4066 quad bi-lateral switch IC in its place. An RC toy car donated the receiver transmitter pair. The receiver signals are monitored by an AVR microcontroller which translates the commands in a proper set of button presses for the video. What you get is a controller that and turn the camera on and set to the proper mode, and the ability to start and stop the recording.

We’ve got some pics of the hardware after the break, and [Leor] posted a bit of the chipmunk video for your enjoyment.

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