Self-Balancing Robot Uses Android and Lego NXT

LEGO NXT + Android = Self Balancing Robot

Self-balancing robots are pretty cool, but sometimes a bit too complex to make. [HippoDevices] shows us that it’s really not that hard, and you can even do it with Lego NXT and an Android device!

First step is to build your two-wheeled robot – go nuts! As long as the Lego NXT motors are strong enough you’ll be able to make most different shaped robots easy to balance. You’re going to need an Android ADK board to provide communication between the Lego motors and your Android device. [HippoDevices] is using their own design, called the Hippo-ADK which is on Kickstarter currently.

This allows your Android device to read the status and control the Lego Motors — from there it’s just a matter of programming it to balance according to the device’s gyroscope.

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Raspberry Pi Turns a Novelty Radio Into a Real Computer

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[Strider19] remembers the 90′s, and a great little novelty radio he had back then. Shaped like a computer, the radio was a typical AM/FM affair, with the monitor serving as a speaker. His original radio was long gone, but [Strider19] was able to find a replacement on everyone’s favorite auction site. With the replacement radio in hand, he set his plan in motion: Turning it into an epic Raspberry Pi Case.

The Raspberry Pi fit great, but [Strider19's] 3.5″ composite monitor didn’t quite make it. Following in [Ben Heck's] footsteps, [Strider19] cut the LCD’s control PCB down to fit the case. A piece of clear polycarbonate protects the fragile LCD from poking fingers. The monitor’s button board, two USB ports, and an external composite input mounted nicely inside the former battery compartment at the rear of the CRT. There’s even enough room back there to hide a USB WiFi adapter.

The Raspi itself fit perfectly into the base of the radio, along with a DC to DC converter, USB hub, real-time clock module, and a whole bunch of wires used to extend the connectors.

The final result is awesome! Thanks to a request on [Strider19's] Reddit thread, we have pictures of Doom running on a (former) radio.  Even Windows 3.1 runs under DosBox, though it took a bit of tweaking to get the display settings just right. Now [Strider19] just needs to figure out how to turn that tiny keyboard into a working model. We think some old school cell phone keyboard hacking may be in order!

 

Upgraded Nerf Gun Keeps Track of your Ammo

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[Paul] and his buddy [Jonathan] recently had a zombie themed Larp event to go to, so in the spirit of making the experience more realistic, they decided to upgrade their Nerf N-Strike Stryfe gun.

They started by cracking open the gun and making note of the available space for a few bells and whistles. Luckily, thanks to traditional plastic injection molding practices — there’s lots of room!

Upgrades include a magazine sensor, a jam sensor, a trigger sensor and a voltmeter to make the gun a little bit smarter. A knockoff Arduino Pro Mini takes in all these inputs and outputs it to a 7-segment LED display for easy visibility. Our favorite part is the ammo sensor, which keeps a tally of how many shots you’ve used. It’s simply an IR photo-diode and IR transistor in a Darlington configuration, connected to the GPIO interrupt pin on the fake Arduino.

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The Crane Game, Oculus Style

crane We’re pretty sure the Hackaday demographic is a a person who sees a giant tower crane lifting beams and girders above a skyline and says, “that would be fun, at least until I have to go to the bathroom.” Realizing the people who own these cranes probably won’t let any regular joe off the street into the cabin, [Thomas] and [screen Name] (see, this is why we have brackets, kids) built their own miniature version with an Oculus Rift.

Instead of a crane that is hundreds of feet tall, the guys are using a much smaller version, just over a meter tall, that is remotely controlled through a computer via a serial connection. Just below the small plastic cab is a board with two wide-angle webcams. The video from these cameras are sent to the Oculus so the operator can see the boom swinging around, and the winch unwinding to pick up small objects.

The guys have also added a little bit of OpenCV to add color based object detection. This is somewhat useful, but there’s also an approximation of the distance to an object, something that would be very useful if you don’t have a three-inch tall spotter on the ground.

Video below.

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Making a Nitinol Wire Inchworm

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[Steven's] at it again with another cool science experiment that isn’t too difficult to do. This time he’s made himself a Nitinol wire inchworm, which actually moves across the table when you apply a switching electrical current to it!

Nitinol is a shape memory alloy which has a cool property that causes it to retain (and return to) a preset shape when heat (or electricity!) is applied. It’s actually quite simple — he’s wrapped the Nitinol wire tightly around a nail, and then heated it to set it to a coiled shape. Now the Nitinol spring can be stretched out flat, but as soon as it is heated, it will attempt to return to its coiled state!

Using some balsa wood and a few other odds and ends he’s taken advantage of this memory effect to make an electric inchworm — check it out after the break!

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Tennis Ball Launcher Has Puppies Running the 100m Dash

Launching Tennis Balls with Ease

[Brian] from 24 Hour Engineer has a friend with arthritis who can’t easily play ball with his new puppy — so [Brian] stepped in and built him this awesome tennis ball launcher.

You see, most tennis ball launchers require a solid flick of the wrist, and since just plain old throwing it is out of the question too, [Brian] had to make him something powerful and easy to use. After sketching out some designs he came up with the basic concept that eventually became what is pictured above.

The frame is made of 2″ PVC pipe, which serves two purposes, support, and safety. The bungee cord launching system is actually contained within the pipe, keeping it out of the way, and free from catching on anything during firing. A pair of pulleys mounted at the cord opening ensure the cord doesn’t wear out.

What we really like is the trigger mechanism [Brian] made out of some carefully cut wood,  a steel corner brace and a few nuts and bolts. It’s a simple mechanism that provides leverage and an easy way to release the bungee cord.  Continue reading “Tennis Ball Launcher Has Puppies Running the 100m Dash”

[Lenore] Eviscerates Her Racing Snail

 

You may have walked past [Lenore's] unassuming card table at Maker Faire this year. But we’re really glad we stopped for a little chat. She went so far as to pull the working parts out of her racing snail to show them to us!

Wait, wait… racing snail? Yeah, this is a pretty neat one from a few years ago. The snail is a relatively large version of a bristlebot (incidentally, we believe bristlebots were originated by EMSL). The thing that’s missing here are the bristles. Instead of using a scrub-brush for this large version, [Lenore] discovered that velvet has a somewhat uni-directional grain. But using a piece of mouse-pad cut to the same footprint as the velvet she was able to get the flat-footed snail to move in a forward direction purely through the jiggle of a vibrating motor.

If this sparked your interest there are tons of other bristlebot variations to be found around here. One of our favorites is still this abomination which shifts weight to add steering.