Build A $360 Synthetic Aperture Radar With MIT’s OpenCourseware

December 18, 2012 by Brian Benchoff 38 Comments

A few profs from MIT’s Lincoln Lab are giving those poor MIT undergrads something to do over winter break: they’re teaching a three-week course on building a laptop-powered radar system capable of radar ranging, doppler, and synthetic aperture imaging. Interestingly, the radar system that teams will build for the class has a BOM totaling $360, and they’re also putting the entire class online if you’d like to follow along and build your own.

From the lecture notes from the course, the radio system is made out of an off-the-shelf LNA, oscillator, and splitter. By connecting two coffee can ‘cantennas’, it’s possible to record a .WAV file from the signal coming from the radar and use MATLAB to turn that audio signal into a doppler radar.

It’s a very ambitious project that goes deep down the rabbit hole of RF and analog design. One of the lecturers made a YouTube demo of the radar in ranging mode; you can check that out after the break.

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The Hexapod Hexacopter

December 18, 2012 by Eric Evenchick 34 Comments

Over at Mad Lab Industries, they had the idea of building a quadcopter that could walk and fly. By combining a hexapod with a hexacopter, they ended up with this creation.

The hexapod part started off with PhantomX Hexapod Kit, but it was far too heavy to fly. To reduce weight, they manufactured carbon fibre parts for the frame and legs. Even with the weight reductions, they still needed to six rotors to keep it stable.

The hexacopter part of the build uses more custom carbon fibre parts to mount the motors. The booms and mounts are also custom built out of aluminium. They used six E-Flite motors, propellers, and ESCs to provide lift.

A variety of controllers are used to run the robot. Two Arbotix devices handle the hexapod control, and a Hoverfly flight controller keeps it in the air. It’s controlled remotely using a Spektrum controller.

They have some ambitious next steps, including a mechanism that disconnects and reconnects the hexacopter and the base. After the break, check out a video of this impressive build in action.

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Tindie Gets Fundraisers For Kickstarting And Group Buys

December 18, 2012 by Brian Benchoff 5 Comments

tindie

The etsy of electronics project, Tindie, has a brand new feature: It’s a Kickstarter-esque endeavor called a Fundraiser that allows you to sell your projects to other electron enthusiasts.

Of course the new Tindie Fundraisers may soon be just another Kickstarter clone for “exciting,” “new,” and “innovative” Arduino dev boards, something we’ve lamented before. We’re really interested in seeing Tindie used as a platform for group buys; a solution to a maker’s special hell where buying one component costs $100, but ten cost $200.

Already there are a few really cool projects up on the Tindie Fundraisers including a breadboardable Parallax Propeller dev board. Yes, someone finally made one that doesn’t cost an arm and a leg.

In addition to the new Fundraisers, [emile] also closed on $500k of seed funding for Tindie. It’s wonderful news for something that is sorely needed by the maker community. Tindie is also hiring, so if you’re a Django/Python wizard go drop everyone’s second favorite robotic dog a line.

244 9 Volt Batteries In Series – Arcing Ensues!

December 18, 2012 by Jeremy Cook 49 Comments

Here’s another hack that we would definitely discourage you from trying at home, 244 9 volt batteries wired in series. There’s really not much more to it than that, but [jersagfast] takes this setup through its paces arcing through air first, a LED light second, and then a CD. The air arc is probably the most impressive, but a CD doesn’t look happy after this kind of abuse either. Around 4:38, a capacitor is abused for yet more arcing.

In theory, 244 9 volt batteries in series should be nearly 2200 volts, but as measured (in sections), it “only” came out to a “measly” 2000 volts. Still plenty of voltage to be harmful or even deadly depending on the current emitted. Passing on this hack at home is strongly encouraged. On the other hand, you should watch the video after the break to see what happens. Much safer. Arcing starts around 1:44!

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Watermelon Air Boat

December 17, 2012 by Mike Szczys 35 Comments

We think you’ll turn a few heads in Central Park if you’re driving a water melon around when everyone else is piloting sailboats. This watermelon is both sea worthy and radio controlled thanks to the work which [Starting Electronics] put into it.

We used this image because it shows you what’s inside of the hull, but you don’t want to miss the thing motoring around an above-ground swimming pool in the clip after the break. The hollowed out shell is quite buoyant and has no problem staying afloat and upright with the addition of a propeller. The parts from a remote control airplane kit have been mounted on a wooden scaffold. This provides plenty of thrust with a servo motor moving turning the prop for directional control. There is no dagger board so the craft is a bit slow to respond to turns. But how responsive do you expect a floating melon to be?

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More Details About Laser Cut Gingerbread Houses

December 17, 2012 by Mike Szczys 18 Comments

Members of Sector67 tried their hands at laser cut gingerbread houses. The Madison, Wisconsin based hackerspace is using the tabbed box method of assembly for the corners of the structure. They’ve also put up a bunch of information about laser settings and published the recipe used to mix up a sheet of gingerbread. This quite a bit more info than was provided with the project we saw a couple of weeks back.

The initial designs were made in Inkscape and then transferred to Corel Draw before heading to the cutter. They’ve got a 150W machine and found that a speed of 15 worked well when the speed was set to 100, with a corner speed of 60. The raw dough was rolled out to 1/8″ thickness. Possibly the best tip coming out of Sector67 is to lay 1/8″ dowels on either side of the dough. This way the rolling pin will stop when it hits the dowels resulting in the best possible uniform thickness. As reported in the previous project the odor generated while cutting is not the most pleasant. But we love the fusion of lasers with the age old process of building with cookies and decorating with candy.

Silent HTPC Build Is An Art Piece For The Livingroom

December 17, 2012 by Mike Szczys 29 Comments

silent-htpc-build

This sexy beast is [DeFex’s] new silent home theater PC. To give you an idea of scale, that motherboard is a Mini ITX form factor. Mounted below it is the solid state drive which is an SLC version chosen because they tend to last longer than the MLC variety. This distinction comes with a price tag that is $100 more expensive.

But we digress. It’s the custom case that really caught our eye with this build. The frame is made of a huge aluminum heat sink. It measures about 7″ by 10″ and sets the final foot print for the computer. An aluminum puck was added to transmit heat from the processor to the heat sink. Holes were drilled and tapped into the heat sink to accept the brass stand offs which hold the motherboard in place.

The near side of the case is a sheet of acrylic. It connects to the rest of the case using 3D printed brackets at each corner. There is an additional bracket on the bottom to hold the hard drive in place. The sides of the case are filled in with bicycle spokes which also find a home in the corner brackets. Now the hard part will be figuring out which orientation looks the best for displaying his fine craftsmanship.

[via Reddit]