Day: July 29, 2011

RGB LED Spectrum Analyzer Coffee Table

July 29, 2011 by 32 Comments

rgb_led_spectrum_analyzer_coffee_table

This year, students working for Texas Instruments as part of their Co-op program were challenged to construct a project around the company’s MSP430 microcontroller. A team of three students, [Max Thrun, Mark Labbato, Ian Cathey] decided to build something that would fit perfectly in any college student’s dorm room – an RGB LED coffee table.

We’ve covered RGB LED tables in the past, but as far as we can tell this is the first MSP430 based unit we’ve seen. Microcontroller aside, the table features a lot of items that are considered “standard equipment” when it comes to these sorts of living room LED installations. The trio installed 128 RGB LEDs into their table, isolating each one using a wooden grid, and used some frosted glass to diffuse the display a bit.

What really makes this table stand out is the software. The team wrote an application that creates a Fast Fourier Transform of whatever music is being played, in order to find beats and generate real-time visualizations for their table. The result is a pleasing display that’s sure to be a hit at parties.

Check out the video below to see their creation in action.

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Improving Audio Output From An HD Radio Receiver

July 29, 2011 by 19 Comments

[Phil] picked up an HD radio receiver when Radio Shack was clearing them out at a 60% discount. But to his disappointment, when he hooked it up the sound left a lot to be desired with limited mid-range and flat bass. After some forum mining he discovered that the optical output didn’t have this problem, and came to the conclusion that the op-amp driving the analog audio-out jack needed some tweaking. He didn’t get his hands on a schematic for the board, but took the advice from some vintage equipment gurus and swapped the stock IC for a Burr-Brown OPA2604AP chip.

This fixed the problem without any other adjustments to the hardware. But while he was in there, he also secured the external antenna connector jack to the chassis for good measure.

If you’re wondering about the particulars of the equipment, [Phil] was hacking an Auvio HD Radio tuner. But he also mentions that Best Buy sells an Insignia NS-HDTUNE which may benefit from the same modification.

Comment System Updates

July 29, 2011 by 88 Comments

We’ve been working hard on this one and finally made a tiny bit of progress.

You will find that comments are now nested.  We can see there are some slight visual issues, but we’re working on it. Please be patient with us.
Another edition you will find is the “report” button. If you find comments offensive, click that button to let us know.

Again, we’re still working through this and have a decent list of quirks that need worked out but it seems to be mostly functional.

Putting A PDP-10 On An FPGA

July 29, 2011 by 41 Comments

[dgcx] has been working on reimplementing a PDP-10/x on an FPGA for the last 2 and a half years. This surprised us because we’re only hearing about this project now.

After designing three versions, [dgcx] eventually ended up with a one-FPGA implementation of a PDP-10 and an awesome PDF writeup. Although PDP-10 emulators do exist, this project isn’t an emulation – the system actually has the 36-bit word length of the original, implemented on five 4096 kilobit SRAM chips. This is a fully functioning replica, and even has CHAOSNET implemented with a small Ethernet controller.

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Adding Auto-off To A Cheap Multimeter

July 29, 2011 by 24 Comments

[Florin] picked up a cheap multimeter in order to make multiple measurements at one time. Unfortunately, he wasn’t very good at remembering to turn it off when he was finished so he burned through some batteries. Why an auto-off feature wasn’t the first thing coded into the firmware we’ll never know, but [Florin] developed his own hardware-based auto-off circuit.

It sounds like he had all of the components necessary for this on hand already. He grabbed an AVR ATtiny25 in a surface mount package. To keep the board small, he didn’t include an ISP header, but instead made long pads that could have wires soldered to them for flashing the firmware. The microcontroller drives an NPN transistor that can cut off the ground path between the multimeter and its battery. A tactile switch is connected to one of the external interrupt pins and, when pressed, gives you 15 minutes of time to use the meter. After that, the chip kills the power and goes into sleep mode. Simple, and small enough to fit inside the case.

[via Dangerous Prototypes]

IR Communications Tutorial

July 29, 2011 by 5 Comments

After seeing our communications via light post , reader [Chris] dropped this handy little link in our inbox. A very good tutorial about using infrared to enable communications between 2 pic micro controllers.

The tutorial covers all the parts you will need, physical wiring and schematics with notes detailing each section of the circuit. It then goes on into basic IR theory, and a simplified push button circuit you can make to see that it is, in fact, working. Once you get the exercise built on some breadboards, he does some software and get some results from it all.

Now in the end this little device was hitting in the neighborhood of 9600 baud, but had to be pretty darn close to each other with a direct line of sight. These  are often accepted as a couple of drawbacks to IR technologies. IR, which has never really vanished, is in use on a lot of devices though. The more you know the better off you are.

Join us after the break for a quick video!

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MIDI Air Drums Let You Play Anywhere

July 29, 2011 by 26 Comments

[Maayan Migdal] wrote in to share a really cool drum kit he constructed that has one special twist – no drums at all. Using a simple MIDI device and an Arduino, his “Air Drums” look pretty sweet.

The hack makes use of a pair of garden rakes, which serve as his drum sticks. The rakes were cut down and modified to allow the addition of accelerometers and some USB cables. The left stick contains a single accelerometer for registering hi-hat hits, while the right stick is armed with a pair of the modules, which are used to trigger snare and crash symbol strikes. He modified a pair of sandals to fit better while drumming before adding a sensor to each shoe. The left sandal contains an accelerometer to register bass drum hits, while the right shoe uses a light sensor to simulate the use of a hi-hat pedal.

We think that the results are awesome, but feel free to check out the video below to see what we mean. If Guitar Hero wasn’t dead in the water on hiatus, we think this sort of setup would make a great replacement for the flimsy drum set that comes with the game.

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