Reverse Engineering A Korg Monotribe

December 3, 2011 by Brian Benchoff 19 Comments

Yesterday, Korg released a firmware update to their ribbon controller synth, the Monotribe. The firmware is just an audio file that needs to be played to the sync input of the box. [gravitronic] thought this was rather interesting, so he decided to decode the monotribe firmware. It’s the first step to custom Monotribe firmware, and on the path towards reverse engineering this neat box.

After converting the firmware update to a .wav, [gravitronic] looked at the file with a hex editor and found that each sample is two bytes, and the left and right channels are the same. That made enough sense, so after getting rid of one channel, he sent it through Python to take a look at the patterns of ones and zeros.

Of course, [gravitronic] arbitrarily chose high = 1, low = 0, and little-endianness. The first result didn’t produce a nice “KORG SYSTEM FILE” in the header, so he tried other combinations until the output file looked reasonable. The result is the actual .bin file that’s going to serve as the basis for a nice homebrew firmware. You can grab [gravitronic]’s Python script here and decode your own firmware.

Building A Computer Around A 6502 Processor

November 30, 2011 by Mike Szczys 24 Comments

When it came time to try out some old-school computing [Quinn Dunki] grabbed a 6502 processor and got to work. For those that are unfamiliar, this is the first chip that was both powerful, affordable, and available to the hobby computing market back in the 1970’s. They were used in Apple computers, Commodore 64, and a slew of other hardware.

The first order of business in making something with the chip is to establish a clock signal. She sourced a crystal oscillator which runs at 1 MHz, but also wanted the option to single step through code. Her solution was to build two clock signals in one. A toggle switch allows her to choose the crystal, or a 555 timer circuit which uses a push button to fire each clock pulse.

Check out the video after the break to see some single stepping action. There’s no memory on board just yet. But the input pins have been hard-wired to voltage or ground to simulate data input. We wondered what she was up to with that HEX Out project which stiffs the logic on the data bus. Looks like it’s extremely useful in this project!

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Earthquake Detector Could Have Helped During Quakepocalypse

November 27, 2011 by Brian Benchoff 13 Comments

[Andrea] built a seismic wave detector that warns of a possible impending earthquake. Because P waves travel much faster than the “make everything shake” S waves, building a device that detects P waves serves as an early warning system that alerts building occupants to go under a door frame. [Andrea]’s build detects these fast-moving P waves and only took an hour to make.

Last August, those of us on the east coast of the US had to live through Quakepocalypse, a magnitude 5.9 earthquake centered around Middle of Nowhere, Virginia. For those of us who have decided to stay, rebuild, and put our garden chairs upright again (so brave…), [Andrea]’s build could have been very useful.

The mechanics of the build is very simple: a pair of springs and levers are electrically wired together so that whenever there’s a sudden shock, a buzzer goes off. It’s very similar to an ancient Chinese earthquake detector that detects P waves by dropping a ball into a frog’s mouth.

While we’re not sure if a few of [Andrea]’s devices would be needed to detect P waves coming in off-axis, the build is simple enough to build dozens of them. Check out the video of the build in action ~~after the break~~ here.

Zero-G Experiments Will Make Some Pretty Pictures

November 16, 2011 by Brian Benchoff 4 Comments

Does a yo-yo work in zero-g? How about a paper airplane? These questions were answered in 1985 on the Space Shuttle Discovery, but reproduction of results is the cornerstone of the scientific method. [Rob] is about to reproduce some of the awesome zero-g pictures by riding on a vomit comet and taking a few pictures of water globes colliding.

For the last few months, [Rob] has had a standby ticket on the G-Force One, a plane that takes passengers on parabolic arcs to simulate microgravity. He was lucky as his standby ticket allowed him to take a few experiments on board, so [Rob] decided there’s just not enough awesome pictures of water colliding in zero-g.

He built a rig out of micro t-slot aluminum. A DSLR is mounted to the frame along with a few ‘test tubes’ containing water. When [Rob] blows through a tube, a small sphere of water will be released to collide with other object. Think of it as the nerd’s version of water splash photography.

Of course, a trip through zero-g wouldn’t be complete without a few more experiments. [Rob] plans on testing a few toys to see if yo-yos ‘sleep’ without gravity (they don’t), and if a grandfather clock works on the moon (there’s a month-long day, so kind of). We can’t wait to see [Rob]’s pictures once he comes back to Earth.

Halloween Hacks: A Jacob’s Lantern Sure To Win The Carving Contest

November 3, 2011 by Mike Nathan 15 Comments

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jacobs-ladder-pumpkin

[Matt] entered himself in a pumpkin carving contest this year, even despite the fact that his artistic skills were a bit…lacking. He knew that he had very little chance of winning the contest unless he had a great gimmick to make his creation stand out, so he started brainstorming.

[Matt] figured that since his design would have to be somewhat simple, he needed something eye catching that he could add to the pumpkin after it went under the knife. Like a bolt of lightning, inspiration struck, and he set off to fetch an ignition transformer along with some wire coat hanger.

He built a makeshift Jacob’s ladder that would fit perfectly inside his hollowed out pumpkin, and proceeded to carve the pumpkin with the “Caution, risk of electric shock” logo, familiar to most anyone that works with electronics. You can see the final result in the video below, which we think looks pretty neat. If he didn’t end up winning the contest, we’d be shocked!

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Old-school Projector Turned Digital

October 31, 2011 by Brian Benchoff 21 Comments

Who hasn’t thought about turning a 1950s slide projector into a digital projector? [Matt] did, but unlike most of us, he actually did it.

[Matt]’s friend [Angus] found an old, single-slide, sans-carousel slide projector in the trash. It’s a wonderful piece of ancient technology with a fabric insulated power cord and bakelite lamp socket. This projector was upcycled to the 21st century by adding a 10 Watt LED and a Nokia 1200 LCD.

For the electronics, [Matt] used an ATmega88 microcontroller. There’s an infrared receiver so the remote from an in-car CD player can be used to advance the slides and turn the projector on and off. The LCD is controlled by a bit of bit-banging from the Mega88, using hard-coded images of Che Guevara, Hendrix, Space Invaders and some old-school Macintosh/Lisa icons. Unlike the screen printed t-shirts at American Apparel, Che is the only authentic image in this project; this projector might have been made after Guevara came to prominence.

With a 10 Watt LED, it’s not the brightest projector on the planet and the picture is a little washed out in a bright room. With dim lighting, it’s a very good project even if the images are static.

Recreating The Commodore PET With An FPGA

October 27, 2011 by Mike Nathan 18 Comments

commodore_pet_fpga_clone

[Thomas’] love affair with Commodore computers spans well over 30 years, and not too long ago he decided to recreate one of his favorite Commodore offerings, the PET. As we have seen with similar undertakings, this sort of project is no easy task, but [Thomas] seems to be making his way along nicely.

Using a Xilinx Spartan-6 FPGA on the Digilent Nexys3 dev board, he has implemented the Pet in Verilog. Like the original, his clone contains 16K of both ROM and RAM, utilizing the same simulated 6502 microprocessor he used on a previous Apple ][+ project. The FPGA version of the computer sports a 640×400 resolution which is twice that of the original, so [Thomas] simply doubled the size of each of the PET’s pixels to fill in the extra space.

[Thomas] has made some great progress so far, including the ability to load games and other programs from cassette images over a serial connection. He says that there are still a few loose ends to tie up, but it all looks good from here!

Continue reading to see a short video of Space Invaders running on he PET recreation.

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