A Very Professional Homemade CNC Router

[Benne] has a small workshop at home so he decided to make a very versatile CNC router for his final project at school. It took him around 6 months to arrive at the result you can see in the image above and what is even more impressive is that he was only 17 years old at the time.

[Benne] used the free cad program Google Sketchup to draw the different parts he needed around the linear rails and ball screws he already had lying around. The CNC’s travel is 730x650x150mm, uses Nema 23 (3Nm) steppers, 15mm thick aluminum plates and 30x60mm aluminum extrusions. In his article, [Benne] gives great advice to those who would like to design their CNC like his, providing very useful links to manufacturers. He estimated the cost of his CNC to be around 1500 euros (about $2000). We’ll let you browse the many lines of his very detailed build log, which makes us wish to be as talented as him even at our age…

Old Fax Machine Shows Signs of Life

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[Dmitry] is a Moscow based artist. He’s also a an avid circuit bender and hardware hacker. His latest project is entitled “signes de vie” or signs of life. [Dmitry] started with an Arduino and an old thermal fax machine. He removed the thermal print head and replaced it with a row of 10 LEDs. These old fax machines would use rolls of paper, cutting each sheet of as it was printed. [Dmitry] kept the roll system, but treated his paper with fluorescent dye. As the paper passes under the LEDs, it pauses for a moment and the LEDs are flashed. This causes a ghostly glow to remain on the paper for several minutes as the next rows are printed.

While [Dmitry] could have made this the world’s biggest tweet printer, he chose to go a more mathematical route. Each printed row of dots represents a generation of one-dimensional cellular automata. Cellular automation is a mathematical model of generations of cells. All cells exist on a grid, and can be alive or dead. The number of neighboring live cells determines if any given cell will live on to the next generation. One common implementation of cellular automation is Conway’s Game of Life. In [Dmitry's] implementation, a bank of switches select which of the 256 common cellular automata rules controls the colony. A second bank selects how long each generation lasts – from 1 to 18 seconds.

We really like how the paper becomes a printed, yet temporary history of the colony. [Dmitry] doesn’t say if he’s using a single long strip of paper, or if he created a loop. We’re hoping for the latter. Finally a useful implementation of the old black fax loop prank.

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A Much More DYI Air Gap Flash Unit

In reaction to the other air gap flash unit we featured a few days ago, [Eirik] sent us a tip about another one he recently made. In his setup, the duration of the flash peak intensity is around 300ns (1/3,333,333 of a second). As a reminder, an air flash unit consists of a circuit charging a high voltage capacitor, a circuit triggering a discharge on demand, a high voltage capacitor and the air flash tube itself. The flash tube contains two wires which are separated just enough to not spark over at max potential. Isolated from the other two, a third wire is placed in the tube. This wire is connected to a trigger/pulse transformer, which will ionize the gap between the two capacitor leads. This causes the gap to breakdown and a spark to form, thereby creating a flash of light.

[Eirik] constructed his flash tube using an olive jar and a glass test tube. As you can see from the (very nice) picture above, the spark travels along the glass test tube, making the quenching much faster than in an open air spark. [Eirik] built his own high voltage capacitor, using seven rolled capacitors of roughly 2nF each made with duct-tape, tin foil and overhead transparencies. For ‘safety’ they are stored in a PP-pipe. A look at the schematics and overall circuit shown on the website reveals how skilled [Eirik] is, making us think that this is more a nice creation than a hack.

Disclaimer: As with the previous airgap flash, high voltages are used here, so don’t do this at home.

Hackerspacing in Europe: WhiteSpace in Gent

IMG_0751 (Custom)

Welcome to the White Space, or as it is more fondly known, 0x20.

We’re glad we made it out to this one — it wasn’t even planned, but after visiting HSBXL, one of the members got us in touch and so we took a chance and got on a train to Gent, Belgium — just in case someone could show us around. We were in luck, and two members showed up to give us the grand tour!

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Fail of the Week: Flaming Brushless Motor Controller

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Yep, smoke and flames are usually a sign that your electronics aren’t functioning as expected. This is actually the second failure encountered while learning about brushless motor controllers.

[Michael Kohn] purchase the motor while working on a different project and it went unused for quite some time. When he came across it again he decided he should learn the not-so-dark art of BLDC control.

The first hurdle was to figure out how to drive the three-wire motor when he had been expecting only two. The answer required him to come up with switching mechanism that allows three states for each wire: positive, negative, and not connected. His solution was to use MOSFETs. It’s a good idea, but unfortunately during the first iteration they were under-spec’d and he scared the crap out of himself when one of them blew up during testing (clip #1 below). After sourcing a more robust set of MOSFETs [Micheal] went back to testing which is when this little fire broke out. The 22 gauge wires connecting the Lithium battery to the driver just couldn’t cut it. See for yourself in the second clip.

It’s been awhile since we’ve said it: Please remember the Fail of the Week is not about ridiculing the hacker who was gracious enough to document his or her failure. It’s about learning from the mistake and discussing alternatives that can help others in the future. For instance, in this case some advice in determining MOSFET specs and wire gauge for any type of motor would be quite helpful. Have at it in the comments.

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Trinket Contest Update #1

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Entries for the Trinket contest are starting to roll in. The challenge was to slap the Hackaday logo onto something, with 20 of Trinket dev boards which Adafruit put up for grabs. Here’s five of the early entries, which we’ll describe in more detail after the jump. Get your entry in by Friday, November 1st for a chance at a prize.

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Building a Ball-Balancing Robot

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If you want a different kind of feedback systems challenge, ditch the Segway-style robots and build one that can balance on a ball. UFactory is a startup in Shenzhen, and this impressive little guy is a way of showing their skills applied to the classic inverted pendulum. At nearly 18 inches tall and weighing just over six pounds, the robot boasts a number of features beyond an accelerometer and gyroscope: it has both a WiFi module and a camera, and can be controlled via a homemade remote control or a Kinect.

The build uses plastic omni-directional wheels attached to 3 brushed dc motors, which attach to the base of the robot with custom-made aluminum brackets. The UFactory gang constructed the robot’s body out of three acrylic discs, which hold the electronics directly above the wheels. The brain seems to be an STM32 microcontroller that connects up to the motors and to the sensors.

You won’t find the code on their Instructable yet, but according to the comments they have plans to make the entire project open source. If you’re desperate for more details, the UFactory team seems willing to provide source code and other information via email. Make sure you see the video after the break, particularly the end where they demonstrate interference and carrying loads. This isn’t the first ball pendulum we’ve seen; take a trip down memory lane with the BallP ball balancing robot from 2010.

[Read more...]

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