Water Glider Prototype

August 17, 2012 by Mike Szczys 48 Comments

[Byrel Mitchell] wrote in to share some details on this water glider which he has been working on with his classmates at the Nonlinear Autonomous Systems lab of Michigan Technological University. As its name implies, it glides through the water rather than using propulsion systems typically found on underwater ROVs. The wings on either side of the body are fixed in place, converting changes in ballast to forward momentum.

The front of the glider is at the bottom right of the image above. Look closely and you’ll see a trio of syringes pointed toward the nose. These act as the ballast tanks. A gear motor moves a pinion connected to the syringe plungers, allowing the Arduino which drives the device to fill and empty the tanks with water. When full the nose sinks and the glider moves forward, when empty it rises to the surface which also results in forward movement.

After the break you can find two videos The first shows off the functionality and demonstrates the device in a swimming pool. The second covers the details of the control systems.

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Autonomous Fixed-wing Drone Threads The Needled In A Parking Garage

August 16, 2012 by Mike Szczys 23 Comments

We’ve got something of a love affair going on with quadcopters, but there’s still room for a little something on the side. This fixed-wing drone can pull off some pretty amazing navigation. MIT’s Robust Robotics Group is showing off the work they’ve done with the plane, culminating in a death-defying flight through a parking garage (video after the break). This may not sound like a huge accomplishment, but consider that the wingspan is over two meters and repeated runs at the same circuit brought it within centimeters of clipping support columns.

Unlike the precision quadcopters which depend on stationary high-speed cameras for feedback, this drone is self-contained. It does depend on starting out with a map of its environment, using this in conjunction with a laser rangefinder and inertial sensors to plot its route and adjust as necessary. We think the thing must have to plan a lot further ahead than a quadcopter since it lacks the ability to put on the brakes and hover. This is, however, one of the strengths of the design. Since it uses a fixed-wing approach it can stay in air much longer than a quadcopter with the same battery capacity.

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LEGO ROV Without A Tether

August 14, 2012 by Mike Szczys 13 Comments

[Brane] built an underwater ROV from LEGO mindstorm parts. Look closely at this image and you should notice something missing. The tether that normally carries power and control lines from an ROV to the surface is missing. This is a wireless solution that lets him control the device using an Xbox controller.

The video after the break shows about five minutes of test drive footage. [Brane] has a big aquarium in which he can test the thing. Since he put it together as his senior engineering project at University it’s likely that this is a testing facility at the school. Here’s the little we know about the hardware: It’s using NXT Mindstorm parts to control the motors, with a sealed chamber for a battery. Connectivity is provided by an XBee module with an NXT adapter board called the NXTBee. A laptop with its own XBee module makes up the other end of communications. Right now [Brane] uses an Xbox controller connected to the laptop, but a standalone device would be easy to build by hacking the XBee and controller together directly.

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Robot Servo Control Using Smartphone Audio Jack

August 14, 2012 by Mike Szczys 10 Comments

[Jim] has an old Android phone he’d like to use as a Robot brain. It’s got a lot of the things you’d want in a robot platform; WiFi, Bluetooth, a camera, an accelerometer, etc. But he needed some way to make the mobile, mobile. What he came up with is a chassis with servos that can be controlled by the phone’s audio port.

To start his adventure he crafted a square wave audio file in Audacity and then played it back on the Android music player. By monitoring the output on an oscilloscope he found the wave was well produced, with peaks of about 1V. With that in mind he designed a circuit using two transistors to amplify the signal, thereby creating a usable input for the servo motors. Each motor has one of these circuits connected to it, with the left and right channels from the audio jack driving them separately. In the clip after the break you can see he even wrote a simple Android app to extend the idea to a more usable level.

This is a similar technique as used by the recon robot we saw about a year ago.

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Roomba 4000 Teardown Ready For Your Doomba Build

August 13, 2012 by Brian Benchoff 3 Comments

In addition to getting a haircut, [Dino] spent his week editing an old video of him tearing down a Roomba 4000. These robots can be picked up for just a few dollars on eBay, making them one of the cheapest bodged up robotics dev platforms available.

After [Dino] goes over how to unscrew the cover and disassemble the Roomba 4000, he goes over the layout of the motherboard and takes a look at the sensors. The wheels on the Roomba are actually very neat pieces of technology with a very cool planetary gear system that is the perfect drive system for your next robot build.

There are a ton of ways to use the electronics in Roombas for a few interesting robotics projects. [Dino] built 2/3rds of a all terrain rocker bogie robot – just like the Curiosity rover – out of a Roomba, and a small two wheeled indoor robot using a Parallax Propeller. If you’re a redditor there’s always the possibility of building a Doomba, but we think [Patrick] has a better idea than a knife strapped to a vacuum cleaner.

As always, [Dino]’s vidia after the break.

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Earthworm Robot Does What Earthworms Do

August 12, 2012 by Mike Szczys 16 Comments

This earthworm robot comes to us from researchers at the Massachusetts Institute of Technology. It is made up of mostly soft parts and manages to inch its way along the ground.

The robot’s “skin” is made from a tube of polymer mesh that will hold up to an awful lot of bending and stretching. As with its biological namesake, locomotion is facilitated by circular muscles. In this case muscle wire, when stimulated with electricity, contracts around the mesh casing. By coordinating these contractions the robot is able to inch its way along.

But it’s not just the method of travel that makes this research project interesting. The bot is also extremely resistant to damage. The video after the break shows the device withstanding several whacks from a mallet and being stepped on by the team that created it.

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