Eradicating Invasive Species With Quadcopters

August 21, 2012 by Brian Benchoff 21 Comments

That right there is Sydney Golden Wattle, a fast-growing invasive species native to Eastern Australia that has the possibility of covering 20 percent of the bushland in Western Australia by the year 2020. [John Moore], a researcher at the Department of Food and Agriculture, wants to put an end to this infestation by destroying large swaths of wattle with a quadcopter armed with weed killer.

The plan for the robotic plant assassins is simple; take aerial photographs of the bushland in Western Austraila and identify stands of individual weeds. [Moore]’s robots are then dispatched to these stands of weeds to spray them down with weed killer.

The quadcopters are armed with a camera, allowing the operator to make sure the robot is hovering directly over the invasive weeds. Considering these weeds are found in somewhat inaccessible places – and the fact that just about everything in Australia is poisonous – these robotic weeders will kill more wattle than what could be done on foot.

We couldn’t find a video of the robot in action, or a demo of the herbicide spay system of [John]’s copter. If you can find one of those, send it in and we’ll put it up.

Thanks to [Michal] for sending this in.

High Voltage ROV Adventures

August 20, 2012 by Mike Szczys 19 Comments

[Eirik] wrote in to share the build log for the third iteration of his underwater ROV. The first two project were completed and tested (you may remember reading about it back in January), but both had issues that caused general failure. Most notably, the introduction of water where he didn’t want it. But this time around he seems to have gotten everything right, successfully taking this little guy down to twenty meters without a leak.

One of the problems he had on version two was supplying electricity from the surface. He needs 12V at up to 10A, and had to use a tether made of 14 AWG to make it happen. That’s a lot of heavy wire to be hauling around and it made the ROV virtually unable to move itself. He wanted to go back to using Cat5e cable but it won’t handle that kind of current. He ended up using an inverter at the surface to up the voltage to 130V, and a switch mode supply on the ROV to get back to 12V. This caused noise on the data lines which he fixed by adding a full-wave rectifer to the inverter’s output.

The dive video after the break shows off the crystal-clear camera shots this thing can capture.

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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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