String Racing Robots Are Here !

January 12, 2016 by Anool Mahidharia 24 Comments

This could be the start of a new thing. [HarpDude] showed off his String Car Racers over on the Adafruit forum. It’s like a small model cable car on caffeine. String up enough of them and go head to head racing with others.

A motor with a small pulley runs over a length of string stretched between 2 posts. Below the pulley, acting as a counterweight balance, is the rest of the racer. A Trinket board, motor driver, 9V battery and a pair of long lever micro switches to detect end of travel. The switches also help reverse the motor. A piece of galvanized wire acts as a guide preventing the String Car from jumping off the string. And discovering the benefits of a micro-controller design, as against discrete TTL/CMOS, old timer [HarpDude] added two operational modes via software. “Pong”, where the String Car keeps going back and forth over the string until it stops of (battery) exhaustion. The other mode is “Boomerang” – a single return trip back and forth.

We are guessing the next upgrade would be to add some kind of radio on the car (ESP8266 perhaps) and build an app to control the String Car. That’s when gaming could become fun as it opens up possibilities. One way to improve performance would be to add two “idler” pulleys in line with the main drive pulley, and then snake the string through the three of them. Now you know what to do with all of those old motors you’ve scavenged from tape drives, CD drives and printers. Let the Games begin!

Thanks [Mike Stone] for tipping us off on this.

EZ-Spin Motor Spins “Forever”

January 1, 2016 by Elliot Williams 90 Comments

Now this isn’t a perpetual motion machine, but it’s darn close. What [lasersaber] has done instead is to make the EZ Spin, an incredibly efficient motor that does nothing. Well, nothing except look cool, and influence tons of people to re-build their own versions of it and post them on YouTube.

The motor itself is ridiculously simple: it’s essentially a brushless DC motor with a unique winding pattern. A number of coils — anywhere from six to twenty-four — are wired together with alternating polarity. If one coil is a magnetized north, its two neighbors are magnetized south, and vice-versa. The rotor is a ring with permanent magnets, all arranged so that they have the same polarity. A capacitor is used for the power source, and a reed switch serves as a simplistic commutator, if that’s even the right term.

As the motor turns, a permanent magnet passes by the reed switch and it makes the circuit. All of the electromagnets, which are wound in series, fire and kick the rotor forwards. Then the reed switch opens and the rotor coasts on to the next position. When it gets there the reed switch closes and it gets a magnetic kick again.

The catch? Building the device so that it’s carefully balanced and running on really good (sapphire) bearings, entirely unloaded, and powered with high impedance coils, leads to a current consumption in the microamps. As with most motors, when you spin it by hand, it acts as a generator, giving you a simple way to charge up the capacitor that drives it. In his video [lasersaber] blows on the rotor through a straw to charge up the capacitor, and then lets it run back down. It should run for quite a while on just one spin-up.

The EZ Spin motor is absolutely, positively not perpetual motion or “over-unity” or any of that mumbo-jumbo. It is a cool, simple-to-build generator/motor project that’ll definitely impress your friends and challenge you to see how long you can get it running. Check out [lasersaber]’s website, this forum post, and a 3D model on Thingiverse if you want to make your own.

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Build Some Entertainment For Young Holiday Guests

December 26, 2015 by Mike Szczys 1 Comment

Need a good excuse to duck out on the family over the holidays and spend a few hours in your shop? [Jens] has just the thing. He built a color-mixing toy that looks great and we’d bet you have everything on-hand necessary to build your own version.

The body of the toy is an old router case. Who doesn’t have a couple might-be-broken-but-I-kept-it-anyway routers sitting around? Spray painted red, it looks fantastic! The plastic shell hosts 6 RGB LEDs, 3 toggle switches, and 2 buttons. [Jens] demonstrates the different features in the demo video below. They include a mode to teach counting in Binary, color mixing using the color knobs, and a few others.

Everything is driven by an Arduino Pro Mini. The lights are APA106 LEDs; a 4-pin through-hole package version of the WS2812 pixels. You could easily substitute these for the surface mount varieties if you just hot glue them to the underside of the holes in the panel. We’d love to see some alternate arrangements for LEDs and a couple more push buttons for DIY Simon Says.

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You Need A Self-Righting Thrust-Vector Balloon Copter

December 25, 2015 by Elliot Williams 15 Comments

Cornell University’s microcontroller class looks like a tremendous amount of fun. Not only do the students learn the nitty-gritty details of microcontroller programming, but the course culminates in a cool project. [Brian Ritchken] and [Jim Liu] made a thrust-vector controlled balloon blimp. They call this working?!?!

Three balloons provide just enough lift so that the blimp can climb or descend on motor power. Since the machine is symmetric, there’s no intrinsic idea of “forward” or “backward”. Instead, a ring of eight LEDs around the edge let you know which way the blimp thinks it’s pointing. Two controls on the remote rotate the pointing direction clockwise and counter-clockwise. The blimp does the math to figure out which motors to run faster or slower when you tell it to go forward or back.

The platform is stabilized by a feedback loop with an accelerometer on board, and seems capable of handling a fairly asymmetric weight distribution, as evidenced by their ballast dangling off the side — a climbing bag filled with ketchup packets that presumably weren’t just lifted from the dining halls.

It looks like [Brian] and [Jim] had a ton of fun building and flying this contraption. We’d love to see a distance-to-the-floor sensor added so that they could command it to hover at a given height, but that adds an extra level of complexity. They got this done in time and under budget, so kudos to them both. And in a world full of over-qualified quadcopters, it’s nice to see the humble blimp getting its time in the sun.

Yep, you heard right… this is yet another final project for a University course. Yesterday we saw a spinning POV globe, and the day before a voice-activated eye test. We want to see your final project too so please send in a link!

Hacking The Leapfrog TV To Play Doom

December 24, 2015 by Richard Baguley 16 Comments

In a few hours, millions of fresh-faced children will be tearing open presents like the Leap TV, a Wii for the pre-school crowd that has a number of educational games. And, once they get bored with them, what could be more educational than fighting your way through a horde of demons to save the earth? Yup, [mick] has hacked the Leap TV console to play Doom. After some poking around he discovered that the Leap TV is built around a quad-core nxp4330q arm7-A processor, with 1GB of RAM and 16GB of flash memory, while the controller links to the main console using Bluetooth LE. That’s more than enough to run Doom on (in fact… too much), so he whipped out his handy compiler and got Doom and SDL running with only a few minor code changes.

This isn’t [Mick]s first such hack: he previously hacked the V-Tech InnoTab, a cheap tablet for kids, which persuaded the manufacturers to release the full source code for the tablet. Will Leapfrog follow suit? That remains to be seen, but in the meantime, [Mick]s work gives us some insight into the internals of this device.

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Decoupling Lego Trains Automatically

December 13, 2015 by Brian Benchoff 25 Comments

Lego train sets were introduced almost 50 years ago, and since then, one thing has been constant: the trains connected with magnets. While this is a supremely simple means of connecting locomotives to rolling stock, there is one big disadvantage. Building decouplers – devices that will separate one car from another – is difficult.

Now, with a clever combination of racks, gears, and wedges, trains can disassemble themselves. They can even do it with an Arduino.

This decoupler works by effectively wedging cars apart from each other. With a motor from an old Lego Technic set, a few gears, shafts, and a rack, a device can be constructed that fits between the rails of a track that raises into the undercarriage of rolling stock.

Because this rolling stock is moved around with a locomotive, all that’s needed to separate two halves of a train is to move the locomotive forward. Yes, it does mean that the connection with the weakest magnet is disengaged – not necessarily the connection you want to decouple. However, with only one car and a locomotive, there’s only one connection to break. Simple enough.

This Lego decoupler can be further improved with an Arduino, a few ultrasonic sensors, and an IR detector to make a fully automatic decoupling siding for a Lego train layout. You can see all this below operating with a full state machine that perpetually switches rolling stock behind a locomotive.

A great use for Legos.

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“Hello Barbie” Under The Knife

November 24, 2015 by Elliot Williams 43 Comments

In February, Google and Mattel introduced their Hello Barbie Internet-connected toy. This Barbie has an internal microphone, a WiFi connection to Google’s voice recognition services, and a speaker to carry on a “conversation” with the targeted child.

Like the folks at Somerset Recon, we’d say that this is an Internet of Things (IoT) device that’s just begging for a teardown, and we’re totally looking forward to their next installment when they pore through the firmware.

On the hardware front, Barbie looks exactly like what you’d expect on the inside. A Marvell 88MW300 WiFi SoC talks to a 24-bit (!) audio codec chip, and runs code from a 16Mbit flash ROM. There’s some battery management, and what totally looks like a JTAG port. There’s not much else, because all the brains are “in the cloud” as you kids say these days.

From day to day we alternate between the promise of IoT and being anti-IoT curmudgeons, so it should come as no surprise that we’re of two minds about Hello Barbie. First, there’s the creepy-factor of having your child’s every word overheard by a faceless corporation with “evil” in their mission statement (see what we did there?). Next, we’re not sure that it’s OK to record everything your child says to a toy and listen to it later, even if you are the parent. Hackaday’s [Sarah Petkus] summarized this neatly in this article.

But mostly, we’re curious about how well the thing actually works and what it will do with naughty words. And who will take on the task of reviving the Barbie Liberation Organization? Now we totally want to go out and buy one of these things.