Embed With Elliot: I2C Bus Scanning

June 25, 2015 by 15 Comments

A lot of great ICs use I2C to communicate, but debugging a non-working I2C setup can be opaque, especially if you’re just getting started with the protocol/bus. An I2C bus scanner can be a helpful first step in debugging an I2C system. Are all the devices that I think should be present actually there and responding? Do they all work at the bus speed that I’m trying to run? If you’ve got an Arduino or Bus Pirate sitting around, you’re only seconds away from scanning your I2C bus, and answering these questions.

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Blinking LEDs For A Timeless Fountain

June 25, 2015 by 15 Comments

We’ve seen a few of these builds before, but the build quality of [Mathieu]’s timeless fountain makes for an excellent display of mechanical skill showing off the wonder of blinking LEDs.

This timeless fountain is something we’ve seen before, and the idea is actually pretty simple: put some LEDs next to a dripping faucet, time the LEDs to the rate at which the droplets fall, and you get a stroboscopic effect that makes tiny droplets of water appear to hover in mid-air.

Like earlier builds, [Mathieu] is using UV LEDs and is coloring the water with fluorescein, a UV reactive dye. The LEDs are mounted on two towers, and at the top of the tower is a tiny, low power IR laser and photodiode. With the right code running on an ATxmega16A4, the lights blink in time with the falling water droplet, making it appear the drop is hovering in midair.

Blinking LEDs very, very quickly isn’t exactly hard. The biggest problem with this build was the mechanics. The frame of the machine was machined out of polycarbonate sheets and went together very easily. Getting a consistent drip from a faucet was a bit harder. It took about fifteen tries to get the design of the faucet nozzle right, but [Mathieu] eventually settled on a small output hole (about 0.5 mm) and a sharp nozzle angle of about 70 degrees.

[Mathieu] created a video of a few hovering balls of fluorescence. You can check that out below. It’s assuredly a lot cooler in real life without frame rate issues.

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Hackaday Prize Entry: Ultimate Circuitbending

June 24, 2015 by 13 Comments

Circuit bending is the process of taking a small electronic toy or musical instrument, soldering wires to pads on the PCB, and hoping the sounds it produces will be cool. It’s not a science by any means, and any good, weird sounds you’ll get out of a Speak ‘N Spell or old MIDI keyboard are made entirely by accident or hours and hours of experimentation.

[Alpha Charlie]’s entry for the Hackaday Prize is the most technologically advanced circuit bending you’ll ever see. He’s using an old digital beat box, the Roland TR-626, with computer-controlled wires between random pads on the PCB.

Until now, you could tell how technically adept a circuit bender was simply by how many switches were on the circuit-bent instrument. [Alpha Charlie] doesn’t need switches. Instead, he’s using a few crosspoint switch ICs to connect different pins and pads on the TR-626’s PCB with an Arduino. All of this is controlled by a touchscreen display, and experimenting with the circuit is as simple as pushing a few buttons. Each ‘bend’ is computer controlled, and can be saved and recalled at will.

Of course, circuit bending doesn’t do anyone any good if it sounds like crap. [Alpha Charlie] doesn’t have to worry there. In the video below, he’s getting some very unique sounds that sound like a choir of angels to dorks like myself that listen to Nintendo music.

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Autonomous Drones Now Carry People

June 24, 2015 by 85 Comments

There are a handful of companies trying to build the first autonomous car, but this project makes us think that they all might be heading in the wrong direction. [Thorstin] wanted to use a quadcopter to transport people, and built a working prototype of an autonomous quadcopter-esque vehicle that is actually capable of lifting a person.

The device isn’t actually a quadcopter anymore; that wouldn’t be able to generate enough lift. It has sixteen rotors in total, making it a sexdecacopter (we suppose). This setup generates 282 pounds of static thrust, which as the video below shows, is enough to lift an average person off of the ground along with the aluminum alloy frame and all of the lithium ion batteries used to provide power to all of those motors.

With the PID control system in place, the device is ready for takeoff! We like hobby projects that suddenly become life-sized and rideable, and we hope to see this one fully autonomous at some point too. Maybe soon we’ll see people ferried from waypoint to waypoint instead of being driven around in their ground-bound autonomous cars.

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Brass Clock Face Etched With PCB Techniques

June 24, 2015 by 17 Comments

Over the last few months, [Chris] has been machining a timepiece out of brass and documenting the entire process on his YouTube channel. This week, he completed the clock face. The clock he’s replicating comes from a time before CNC, and according to [Chris], the work of engraving roman numerals on a piece of brass would have been sent out to an engraver. Instead of doing things the traditional way, he’s etching brass with ferric chloride. It’s truly artisan work, and also provides a great tutorial for etching PCBs.

[Chris] is using a photoresist process for engraving his clock dial, and just like making PCBs, this task begins by thoroughly scrubbing and cleaning some brass with acetone. The photoresist is placed on the brass, a transparency sheet printed off, and the entire thing exposed to four blacklights. After that, the unexposed photoresist is dissolved with a sodium carbonate solution, and it’s time for etching.

The clock face was etched in ferric chloride far longer than any PCB would; [Chris] is filling these etchings with shellac wax for a nice contrast between the silvered brass and needs deep, well-defined voids.

You can check out the video below, but that would do [Chris]’ channel a disservice. When we first noticed his work, the comments were actually more positive than not. That’s high praise around here.

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Shirt Design Stencil

Shirt Printing With Freezer Paper

June 24, 2015 by 15 Comments

There’s a pretty good chance that you’ve wanted to add a graphic or design to a t-shirt some time in your life. There are certainly ways to do it but most of us don’t have silk screening equipment or a steady enough hand to have the end product look cool. Lucky for us, [UrbanThreads] has put together a stenciling tutorial for personalizing garments. The process is easy and inexpensive. The results are good, although it can be time-consuming if the pattern is intricate.

To get started, a black and white graphic is printed on a sheet of paper. The design is then taped to a sheet of the secret ingredient: freezer paper. The two sheets are then placed on a table with the freezer paper up. Since the freezer paper is semi transparent, the printed out design shows through. It’s now time to use an exacto knife and trace the design while cutting through the freezer paper. The two sheets are then removed from each other and the freezer paper is put wax-side-down on the garment and ironed into place. The wax melts and acts as a temporary adhesive to hold the stencil down. At this point, fabric paint can be sprayed or dabbed on with a brush (avoid brushing back and forth as it may lift the stencil). Once the paint is applied, the stencil is removed and the paint is allowed to dry. According to [UrbanThreads] the freezer paper doesn’t leave any wax or residue on the garment.

For more garment modding, check out t-shirt bleaching or get ambitious with this DIY screen printing setup.

Machine Metal With Electricity: An EDM Attachment For 3D Printers

June 24, 2015 by 54 Comments

[SuperUnknown] has revealed a secret project he’s been working on. He’s cooked up an EDM attachment for 3D printers, or any CNC machine for that matter. Electrical Discharge Machining (EDM) is a method of using sparks to machine metal. EDM isn’t a new technology, in fact commercial machines have been around since the 1960’s. If you’ve ever had an arc scar up your multimeter probes, you’ve unwittingly done a bit of EDM.

The theory behind EDM is simple: High voltage between the tool and workpiece causes sparks to jump between them. Each spark erodes the workpiece (and the tool). Big EDM machines perform their magic in a liquid which acts as both a dielectric and a flushing medium. This liquid can be anything from deionzed tap water to specially formulated oil. [SuperUnknown] is using good old-fashioned tap water.

edm-roughAs you can imagine, a single spark won’t erode much metal. EDM machines fire tens of thousands of times per second. The exact frequencies, voltages, and currents are secrets the machine manufacturers keep close to their chests. [SuperUnknown] is zeroing in on 65 volts at 2 amps, running at 35 kHz. He’s made some great progress, gouging into hardened files, removing broken taps from brass, and even eroding the impression of a coin in steel.

While we’d love to say this is a free open source project, [superUnknown] needs to pay the bills. He’s going with crowdsourced funding. No, not another Kickstarter. This project is taking a different route. The videos of the machine will be uploaded to YouTube and visible to [superUnknown’s] Patreon supporters. They will also be available for rent using YouTube’s new rental system. [SuperUnknown] has pledged to figure out a way to make the content available for starving college students and others with limited incomes.

Based upon his previous adventures with lil’ screwy, his homemade 100 ton press, and various other projects on the Arduino verses Evil YouTube channel, we think [superUnkown] has a pretty good chance of making home EDM work. Click past the break to see two videos of the 3D printer EDM toolhead in action. We should mention that [SuperUnknown] is rather colorful with his dialogue, so make sure you’re using headphones if you’re at work.

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