An Engineer’s Emergency Business Card

December 2, 2013 by James Hobson 46 Comments

breakout_3

We’ve seen lots of circuit board business cards before, but none quite like this. [Saar] calls it the Engineer’s Emergency Business Card.

Since he actually makes a living from making circuit boards, it made sense for him to make a truly functional card. But unlike some of the fancier cards we’ve seen, you can’t plug it into your computer, or even open a beer with it! In fact, all it does is light up when a voltage is applied across the main pins.

But wait — why are all the components in through holes? Well, according to [Saar], that’s because it’s designed to be the electrical engineers emergency kit!

When all hope is lost, the MacGuyver engineer could snap out one of the components and save the day. Recall the countless times you desperately needed a 1 KOhm resistor to fix an amplifier at a party, only to see the girl you were trying to impress slip away with an OCaml programmer? Never again with this little kit. You even have 2 cm of solder in there to make sure the connection’s electrically solid!

We love it. Whether or not anyone will ever successfully use it in an emergency situation such as [Saar’s] hypothetical one is another question altogether. But we do have to give him creativity points for it, the artistic traces look awesome!

Levitating Wireless LED Ring

December 1, 2013 by James Hobson 10 Comments

magnetic levitation

Here’s an impressive example of a completely home built magnetic levitation setup… with wireless power transmission to boot!

[Samer] built this from scratch and it features two main sub-systems, a electromagnet with feedback electronics and a wireless power transfer setup.

The ring of LEDs has a stack of neodymium magnets which are levitated in place by a varying magnetic field. This levitation is achieved by using a Hall effect sensor and a PID controller using a KA7500 SMPS controller.

The wireless power transmission uses a Class E DC/AC inverter that operates at 800KHz. Two coils of wire pass the current between the stand and the LEDs.

It’s very similar to a build we featured last year, but it’s a great hack, so we had to share it! Check out the video after the break.

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Quadcopters Go Inverted By Reversing Their Motors

November 26, 2013 by Adam Fabio 17 Comments

Inverted Quadcopter? That generally means a crash is soon to follow. Not so for a new crop of quadcopter fliers. These new quadcopters are capable of sustained inverted flight. We’ve seen inverted quadcopters before here on hackaday. However, previous inverted quadcopters always used collective pitch to control the thrust produced by the blades. Collective pitch on a quadcopter is much simpler than it is on the main rotor of a traditional helicopter. R/C and full-scale helicopters mix collective and cyclic pitch to articulate the main rotor blades. A quadcopter only needs the collective portion, which is similar to a traditional helicopters tail rotor mechanism, or a variable pitch prop on an airplane.

These new quadcopters are using a much simpler method of flying inverted: Spin the motors backwards. Quadcopters control their flight by quickly varying the speed of rotation of each motor. Why not completely reverse the motor then? Today’s brushless outrunner motors have more than enough power to quickly reverse direction. The problem becomes one of propellers. Standard propellers are designed to create thrust in one direction only. Every quadcopter uses two clockwise rotation and two counterclockwise rotation propellers. Propellers will generate reverse thrust if they are spun backwards, however they will not be as efficient as they would when spinning the direction they were designed for. The quad fliers have found a partial solution to this problem: Remove the curve from the blade. R/C propeller blades are sold by diameter and blade pitch. The pitch is a measure of the angle of attack of the blades. R/C blades also have an airfoil style curve molded into them. Removing this curve (but not changing the pitch) has helped the problem.

This final problem is control systems. Since quadcopters already are relying on computer control for basic flight, it’s simply a matter of loading custom firmware onto your flight board to support motor rotation reversal. Speed controls also have to be capable of reverse rotation, which means new firmware as well. We’re curious to see how the quadcopter community settles on the control systems for inverted flight. The R/C helicopter community went through several iterations of control systems over the years. At one point they were using “Invert switches” which reversed controls as well as handled the collective pitch changes. As time went on, these switches fell out of favor and are now known as “Crash switches” due to the result of accidentally hitting one while flying, or before engine start.

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Mini Supergun PCB

November 25, 2013 by Brian Benchoff 18 Comments

A few decades ago, Japanese manufacturers of arcade games realized they should make a connector for all their boards that provides the power, controller, video, and audio I/O. This became the JAMMA standard and it make arcade owner’s lives awesome. Because you can buy arcade boards off the Internet, arcade enthusiasts figured out they could build their own console with an ATX power supply, AV connectors, and a few controllers. These ‘superguns’ as they’re called are big devices with wires all over the place. [Charlie] wanted to condense the size of his supergun and ended up creating a single PCB solution (link dead, try the Internet Archive version).

The JAMMA compatable boards require a few power connections; +5 V, +12 V, and -5 V. Of all the boards [Charlie] has collected so far, he realized only one used the negative supply. This, along with a big 12V laptop power supply, means the only power connection for this mini supergun is a single barrel connector.

For the controls and A/V, DSub and SCART connectors are commonplace. Laying these parts out in Eagle resulted in a single-sided board that is easily fabbed by etching with a toner transfer at home.

There are a few problems with the build, as [Charlie] admits. Some of the pins on the JAMMA connector aren’t on the board. These are only ground pins on the pinout, and so far everything works okay. It’s still a great project, though, that turns old arcade boards into a playable device with a minimal amount of hardware.

Pedaling At 128km/h

November 24, 2013 by James Hobson 43 Comments

[Donhou] had a dream. To create a road bike capable of reaching 100mph (160km/h).

He damn well near did it too. The goal of this project wasn’t to set a land speed record, but more of an experiment in design, and building a really fast bike that still looks like a bicycle. In case you’re wondering though, the land speed record is currently set at 167mph by [Fred Rompelberg] who was drafting behind a dragster on the Salt Flats of Bonneville.

The bike features custom everything; a welded lightweight frame using Columbus Max tubing (to help with speed wobbles), super low handlebars for aerodynamics, and a massive 104 tooth chainring which almost scrapes the ground as you pedal. Even the rims and tires are unique — regular bicycle wheels just aren’t designed to go that fast.

We aren’t even bike nuts, but we thoroughly enjoyed the awesome 9-minute documentary on this project. Check it out after the break.

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Building A Crystal Clear Whiteboard

November 22, 2013 by Mike Szczys 76 Comments

[Michael Peshkin] teaches mechanical engineering at Northwestern University. He likes to use diagrams to illustrate his point, but he also likes to face his students when doing so. His solution was to develop this clear whiteboard which ends up unlocking a lot more than just some hand-drawn schematics.

It’s a bit hard to see what he’s written on the board in the image above but squint and see if you can figure out what’s wrong with this style of teaching? Everything he’s writing is backwards. That’s not actually a problem in this case as [Michael] uses flip teaching. He records and posts all of his lectures online. Classroom time is then used for question and answer on the lecture subjects. In order to get the text to read the correct way he just bounces the camera off of a mirror.

The board itself is a huge sheet of tempered glass attached to the metal frame using bolts through holes in the pane. This leave the edges free. He added extruded rail to the top and bottom to embed strips of LEDs. They light the inside of the glass, and excite the fluorescent dry erase marker ink making it much more visible. [Michael] didn’t stop with the board, he also rigged up a lighting system that gives him a lot of options, and uses a monitor for dealing with digital overlays. He can put up a diagram on the computer, watching the monitor to see where his marker is making annotations. All this happens in real-time which means no post production! See a demo of these features after the break.

This could all be done without the glass at all, but that would make it quite a bit more difficult for the person doing the writing.

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Human Powered Hydrofoil, The Wingbike!

November 14, 2013 by James Hobson 22 Comments

[Steven] has been working for the past year on a very cool pedal powered hydrofoil, which he calls the Wingbike.

We’ve seen plenty of trampofoils before, which are hydrofoils that can convert a human bouncing up and down… to horizontal movement. There have even been some pedal powered versions before, but its a rather tricky mechanism to get just right.

[Steven] has built his Wingbike almost entirely out of carbon fiber, and it only weighs 10kg.The biggest problem is balance, as you’re about 1.5M above the foils. If you lean too much, you fall. If you slow down too much, you sink. The current model he is working on has fairly large foils, which does help a bit with the balance, but that also increases the amount of energy required to propel it. He plans on creating new designs with much smaller and faster foils in the future.

Unfortunately, the water is getting quite cold in the Netherlands, so he’s going to spend the rest of the winter months optimizing the bike from a design perspective. Stick around after the break to see his latest successful test video!

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