[Jeri Ellsworth] On Making Her C64 Bass Keytar

July 9, 2012 by Mike Szczys 26 Comments

[Jeri Ellsworth] finally set aside some time to talk about the build process for her Commodore 64 bass keytar. We think what started by taking a band saw to the guitar body ended up as a fantastic new instrument.

When she was showing off the project at Maker Faire we really only got a cursory look at what it could do. Her most recent video covers all that went into pulling off the project. Once the bulk of the guitar body was gone she tore the guts out of a dead c64 in order to mate the case with the guitar neck. Always the craftsman, she altered the computer’s badge to preserve the iconic look, then went to work adding pickups to each string using piezo sensors. This was done with Maker Faire in mind because magnetic pickups would have been unreliable around all of the tesla coils one might find at the event. These were amplified and filtered before being processed via an FPGA which connects to the original c64 SID 6581 chip.

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[Jeri] Builds A C64 Bass Keytar

May 23, 2012 by Caleb Kraft 23 Comments

[Jeri] built this really cool C64 bass Keytar from a commodore64 and a cheap bass guitar. She’s using an FPGA to do the string detection and the key scanning, it then sends everything to the original 8bit sound chips. The reason that she is using a bass guitar is that the commodore sound chip only has 3 channels. There’s an interview with her from the maker faire, and if you keep watching, there are some other interesting projects too.

She notes that the implementation she went with has many performance issues due to the overtones the strings create when played. If she did it again, she’d go another route. Since [Jeri] has previously created the fully functional C64 games on FPGA, maybe she’ll add some video synth to this down the road.

Valve Scoops Up Bright Young Electrical Engineers

April 21, 2012 by Caleb Kraft 22 Comments

Several bright young engineers have been swiped up to work for Valve. Yes, that Valve, the game company. Amongst them are [Jeff Keyser] aka [Mighty ohm] and [Jeri Ellsworth], both names that we have seen on these pages many times. We’ve heard that Valve is a fun and very unique company to work for. Apparently there’s no solid hierarchy.

What we, and everyone else in the universe wants to know is what they are building! There were rumors and speculation of a game console that were quickly squashed. [Michael Abrash] let out some information in an interview that he was doing R&D into wearable computing. He also points out that he was not making a product. So, let the speculation begin!

We asked [Jeri] if this meant she couldn’t publish her own hacks anymore due to contractual agreements, but she said that she can still do them and has some cool stuff coming out soon.

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Pick Up That Can, [Jeri]

December 4, 2011 by Brian Benchoff 10 Comments

We all need an excuse to play Half-Life 2 sometimes. [Jeri Ellsworth] put together a My First Crowbar controller to throw a few headcrabs across the room. It’s pretty much Half-Life 2 for the Wii.

The build is very simple – just a tilt switch hot glued to the underside of a childs-size crowbar. Two leads go from the tilt switch to the contacts on a (PS3?) controller. All you need to do to attack is swing the crowbar wildly.

[Jeri] has us wondering what other awesome game controllers could be made. Of course we’ve been wanting a real-life Gravity Gun or Portal Gun for years now, but right now we’re thinking about a real Katamari. We might need more hot glue.

As far as building our own, we’re thinking about using one of the Cheap DIY tilt switches we saw the other day. It’s a simple build, and sure looks like a lot of fun.

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[Jeri Ellsworth] Builds A Software Radio

July 19, 2011 by Brian Benchoff 27 Comments

[Jeri Ellsworth] has been working on a direct conversion receiver using an FPGA as an oscillator and a PC sound card DSP. Being the excellent presenter she is, she first goes through the history and theory of radio reception (fast forward to 1:30), before digging into the meat of the build (parts 2 and 3 are also available).

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[Jeri’s] Dress Lights Up When Someone Invades Her Personal Space — Step Back Nerds!

June 1, 2011 by Mike Szczys 34 Comments

[Jeri] threw down the geeky fashion gauntlet by building this LED enhanced dress. She chose to assemble the project for her trip to BarBot 2011, and we can’t think of a more appropriate setting for such a garment. It uses a motion sensor to set off a delayed pattern of blue lights hidden underneath the fabric.The best part of the hack is the instamatic camera. It looks like a fashion accessory, but it’s really hiding all of the circuitry for the lights.

Inside the camera a PIR sensor waits until it detects motion, sending a signal through an op-amp to the trigger circuitry. A 74LS14 Schmitt Trigger chip teams up with some resistor-capacitor timer circuits to build a delay chain for the LEDs. This way, after motion is detected the LEDs come on and off in a staggered pattern that doesn’t require a microcontroller and is very pleasing to the eye. See the Analog win for yourself after the break.

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A Bright Idea

May 30, 2011 by Kevin Dady 43 Comments

[Jeri Ellsworth] had a bright idea – a brain-activated light bulb that floats above your head. While out and about, she saw some guy with a video game icon attached to metal rod sticking out of his backpack. The rod made the icon appear to be floating above his head (think The Sims), which was the inspiration for this LED powered light bulb. The bulb is connected to a metal rod, as well as a metal hoop which is springy enough to keep a pair of electrodes snugly attached to your head.

Those electrodes, along with a third probe used for noise reference, are hooked up to a AD620 instrumentation amplifier. With the help of op amps, it modulates the red or green LEDs that are attached to the back side of the light bulb. The end result is an amusing way to show brain activity while being grilled on a Q/A panel, or while just wandering around taking in all the amazing sights presented at Maker Faire.

Join us after the break for a video demonstration.

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