All Your Displays Are Belong To Us

September 26, 2016 by Elliot Williams 23 Comments

Artist and Hackaday reader [Blair Neal] wrote in with his incredible compendium of “alternative” displays. (Here as PDF.) From Pepper’s Ghost to POV, he’s got it all covered, with emphasis on their uses in art.

There’s an especially large focus on 3D displays. Projecting onto screens, droplets of water, spinning objects, and even plasma combustion are covered. But so are the funny physical displays: flip-dots, pin-cushions, and even servo-driven “pixels”.

We really liked the section on LCDs with modified polarization layers — we’ve seen some cool hacks using that gimmick, but the art pieces he dredged up look even better. Makes us want to take a second look at that busted LCD screen in the basement.

We’re big fans of the bright and blinky, so it’s no surprise that [Blair] got a bunch of his examples from these very pages. And we’ve covered [Blair]’s work as well: both his Wobbulator and his “Color a Sound” projects. Hackaday: your one-stop-shop for freaky pixels.

[Blair]’s list looks pretty complete to us, but there’s always more out there. What oddball displays are missing? What’s the strangest or coolest display you’ve ever seen?

Catching Lightning With High Voltages And A Kite

September 25, 2016 by Moritz Walter 44 Comments

Flying a kite on a stormy day is not the wisest thing to do, except, of course, you’re intentionally trying to catch a lightning bolt. The guys from [kreosan] replicated the famous experiment, with which Benjamin Franklin once set out to prove the electrical nature of lightning.

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Scratch-Built EV From Hoverboards

September 22, 2016 by Bryan Cockfield 14 Comments

Electric vehicles are everywhere now. Even though battery technology hasn’t had the breakthrough that we need to get everyone out driving an electric car, the price for batteries has dropped enough that almost anything else is possible. The hoverboard was proof of this: an inexpensive electric vehicle of sorts that anyone who was anyone in 2015 had. Taking his cue from there, [Harris] used off-the-shelf parts normally used for hoverboards to build his own battery-powered trike.

The trike is homemade from the ground up, too. The H-frame was bolted together using steel and lots and lots of bolts. Propulsion comes from a set of hub motors that are integrated into the wheels like a hoverboard or electric bicycle would have. Commonly available plug-and-play lithium batteries make up the power unit and are notably small. In fact, the entire build looks like little more than a frame and a seat, thanks to the inconspicuous batteries and hub motors.

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Hi-Tech Tool For Measuring Your Kid’s Height

September 22, 2016 by Steven Dufresne 22 Comments

Sure we can have our kids back up against a wall, force them to stand up straight, and use a ruler on their head to mark their height on the wall, but what kind of hacker would we be? There isn’t a single microcontroller or any electronic component involved! The DIY-family that calls themselves [HomeMadeGarbage] stood tall and came up with a high-tech tool to measure their kid’s height.

In place of the ruler they got a small wooden box to place on the head. Under the box, at the rear end facing down, they mounted a VL53L0X laser ranging sensor. With a range of 2 meters it’s sure to work with any child. But the box has to be sat level on the child’s head, otherwise the laser will be pointing down at an angle. To handle that they put an MPU6050 6-axis motion sensor in the box along with an Arduino Nano to tie it all together. A LCD display, measurement push-button and LED are mounted outside the box on the rear facing side.

To use it, a parent sits the box on the child’s head, making sure the laser sensor isn’t blocked and can see the floor. The LCD shows the height, along with the acceleration in the x and y directions. The LED is red if the box isn’t level and green if it is. Holding the measurement button pressed puts the tool in measurement mode and when it’s level, the LED turns blue and the LCD display freezes so you can make a note of the height. You’re good for a while, depending on your child’s age. See it being used to measure a child after the break as well as an additional clip showing what the output looks like when waving a hand up and down below it.

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Brushless HDD Motor Driver From 9V And Painter’s Tape

September 21, 2016 by Mike Szczys 24 Comments

Hard drives work by spinning platters full of magnetized data while a read/write head very quickly harvests or changes bits as needed. Older (or perhaps cheaper) drives spin at 5400 RPM, better drives spin at 7200 RPM, and elite drives (that mortals like you never shell out for) spin in the 10k-15k RPM range. This spinning is thanks to a sweet combination of a bearing and a brushless DC motor.

Unfortunately you can’t drive a brushless motor without a brushless motor driver. Well, of course that’s not absolutely true — and [Tommy Callaway] has certainly hacked together a crude exception to the rule. He’s using a 9-volt battery and some blue painters tape to drive a brushless motor.

Brushless motors do their thing by placing permanent magnets on the rotor (the part that spins) and placing multiple stationary coils of wire around it. Brushless motor drivers then energize these coils in a vary carefully timed pattern to continuously push the rotor magnets in the same direction.

[Tommy] wired up his 9V to one of these coils and observed that it holds the rotor in position. He then began playing around with different ways automatically break the circuit to de-energize the coil at just the right time. This means using the spinning center of the hard drive as part of the circuit, with blue painter’s tape in alternating patterns to create the timing. Is this a brushless motor driver, or has he just re-invented the brushed motor?

If this workbench trick leaves you wanting for some hardcore BLCD action, you can’t go wrong with this $20 offering to push motors at very high speeds.

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RC Drag Racing Christmas Tree And Speed Trap

September 20, 2016 by Steven Dufresne 11 Comments

In the drag racing world, a Christmas tree is the post at the start line that sequentially lights up a set of yellow lights followed shortly after by a green light to tell the drivers to go, the lights obviously giving it its seasonal name. Included at the base of the tree are lasers to detect the presence of the cars.

[Mike] not only made his own Christmas tree for his RC cars, but he even made an end-of-track circuit with LED displays telling the cars how long they took. Both start and finish hardware are controlled by Pololu Wixel boards which has TI CC2511F32 microcontrollers with built-in 2.4 GHz radios for wireless communications.

In addition to the LEDs, the Christmas tree has a laser beam using a 650nm red laser diode for each car at the start line that’s aimed at a TEPT5600 phototransistor. If a car crosses its beam before the green light then a red light signals the car’s disqualification.

The end-of-track circuit has 7-segment displays for each car’s time. [Mike] designed the system so that the Christmas tree’s microcontroller tells the end-of-track circuit’s microcontroller when to reset the times, start the times, and clear the times should there be a disqualification. The finish line controller has lasers and phototransistors just like the starting line to stop the timers.

Oh, and did we mention that he also included 1980’s car racing game sounds? To see and hear it all in action check out the video after the break. If the cars seem a little drunk it’s because pushing left or right on the controller turns the wheel’s fully left or right.

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