The Most Minimal Homebrew Computer

October 21, 2013 by 31 Comments

Perfection is achieved not when there is nothing more to add, but when there is nothing left to fail. Going by that metric, [Stian]’s three-chip 6502 homebrew computer is the epitome of perfection. It’s a real, working, homebrew retrocomputer using only three chips: a CPU, some RAM, and a microcontroller to bootstrap the computer and provide a video output,

The key to this minimalist build is having the entire boot process controlled by an ATMega16 microcontroller, This interfaces to the 6502 through a dual-port SRAM, a 1 kilobyte Cypress CY7C130. This dual-port RAM allows the CPU and microcontroller to access the same bit of memory, making it easy to bootstrap a computer from a bit of AVR code.

Output is provided with [Stian]’s ATMega video text generator putting a 37×17 characters on any television with an RCA jack. While input isn’t handled yet, [Stian] says it should be possible with his AVR PS/2 keyboard library.

While other 6502 homebrew computers such as [Quinn Dunki] Veronica can reach unparalleled heights of complexity, there is a lot to be said about the minimalism of [Stian]’s three-chip computer. With some clever coding and a modified parts list, it may well be possible to put a retrocomputer in the hands of everyone with a bare minimum of cost and parts.

Introducing The Shapeoko 2

October 21, 2013 by 39 Comments

For all the 3D printers that hit the Hackaday tip line, it’s surprising we don’t see more CNC routers. They’re arguably more useful tools, and with the ability to mill wood, plastic, and non-ferrous metals, open up the door to a whole bunch more potential builds. One of the most popular – and certainly one of the least expensive – CNC routers out there, the Shapeoko, just received a huge update that makes this minimal machine even more capable.

The new Shapeoko 2 keeps the same V wheel on an aluminium extrusion design with Makerslide, but fixes a few problems that limited the original Shapeoko. There’s a larger work area on this version, and the Y axes feature dual stepper motors. The biggest feature, we think, is the ability to handle materials larger than the machine itself thanks to its open front and back.

The Shapeoko 2 is available in two versions, a $300 mechanical kit that requires you to go out and get some motors, a power supply, and a grblShield, the full version, for $650, includes everything you’ll need to start routing wood metal and plastic at home.

Adventures In Hackerspacing: Freeside Atlanta, Part II

October 21, 2013 by 7 Comments

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This week on Adventures in Hackerspacing, Freeside Atlanta Part II: Hacking the Hackerspace!

After learning about the culture behind the space, I was eager to ask hackerspace veterans [Alan] and [Steven] about nuts and bolts, about behind-the-scenes crucial decisions, and one question in particular: What’s the most important requirement for a hackerspace? [Alan] jumped in with this response:

Number one by and far is a willing landlord. I think if you have a willing landlord everything else is incidental. You make it hard on yourself if you are on the second story, but take the second story if you have a willing landlord.

That wasn’t the answer I was expecting, but when you look around Freeside, it starts to make sense…

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Piano Repurposed As A Resonant Synth Speaker

October 21, 2013 by 10 Comments

piano-synth

[Richard] recently rediscovered some files from a hack he did back in 2004. He was experimenting with exciting piano strings via electromagnetic fields. The idea shares some elements with the self tuning piano we saw back in 2012. Piano strings, much like guitar strings, are made of steel alloys. This means they create electricity when vibrated in a magnetic field. This is the basic principle upon which electric guitar pickups are built. The idea also works in reverse. The strings will vibrate in response to a modulated electromagnetic field. Anyone who has seen an E-bow knows how this can be applied to the guitar. What about the piano?

[Richard] started with the Casio CZ-101, a classic synth in its own right. The Casio’s output was run through a Peavy 100 watt amplifier. The amplified output was then used to drive custom coils mounted on a piano. The coils had to be custom wound to ensure they would be compatible with the 4 – 8 ohm impedance expected by the amplifier. [Richard] ended up winding the coils to 28 ohms. Six of these coils in parallel put him just over the 4 ohm mark. The coils effectively turned the piano into a giant speaker for the synth. In [Richard’s] write-up (word doc link) he mentions that the strings basically act as a giant comb filter, each resonating strongly in response to frequencies in its harmonic series.

The results are rather interesting. The slow attack of the magnetic fields coupled with the synth’s patch results in a surprising variety of sound. The three examples on [Richard’s] blog vary from sounding like a power chord on a guitar to something we’d expect to find in an early horror movie. We would love to see this idea expanded upon. More efficient coils, and more coils in general would add to the effect. The coils on various string groups could also be switched in and out of the system using MIDI control, allowing for even more flexibility. Continue reading “Piano Repurposed As A Resonant Synth Speaker” →

Pet Water Warden

October 21, 2013 by 42 Comments

This weekend’s Make project is a great one for pet owners — an automatic water bowl refilling device!

It’s a fairly simple build, utilizing an old water jug, an Arduino, an aquarium pump, and some home-made water sensors. As always, MAKE has a very thorough guide, and the estimated build time is only an hour or two. They even threw in the ability to Tweet it’s status, including when the reservoir is empty.

But are we over-complicating this? A gravity based water feeder using the jug could work just as well. Sure, you wouldn’t get Twitter updates, but we hope you’re around your pets long enough to know when they’re thirsty.

A more refined version of this could include a solenoid water valve tapped into your house, eliminating the need of the reservoir and making this project a bit more useful. But even that might be a bit much, do we really need the Arduino?  What about a spring-loaded water bowl that breaks a contact when the bowl is empty? Hook that up to a 5 second timer relay controlling the water valve, and you’ve simplified the project quite a bit!

After the break, check out the video to get some more ideas!

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Walter Is A Robot Head Built From Scratch.

October 21, 2013 by 21 Comments

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[Chris] has put together a robot head that is impressive at first sight. [Chris’] robot, Walter II, becomes even more impressive when you realize that [Chris] built every single part from scratch. Many of Walter’s parts were created using machines [Chris] built himself. Walter is a robot neck and head. His upper neck joint is based upon three bevel gears.Two steppers drive the side gears. When the steppers are driven in the same direction, Walter’s head nods. When they are driven in opposite directions, the head turns. The end result allows Walter’s head to be panned and tilted into almost any position.

A second pair of motors raise and lower Walter’s neck via a chain drive. What isn’t immediately visible is the fact that a system of gears and belts maintains the tilt on Walter’s head as his lower neck joint is actuated. For example, if Walter’s head is facing directly forward with his neck raised, one would expect him to be facing the ground when the neck is lowered. The gear/belt system ensures that Walter will still be facing forward when the neck joint reaches its lower limit. All this happens without any movement of the neck motors. [Chris] definitely put a lot of thought into the mechanical design of this system.

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