Solar And Wind Could Help Support Ethiopia’s Grand Dam Project

Ethiopia is in the midst of a major nation-building project, constructing the Grand Ethiopian Renaissance Dam (GERD). Upon completion, GERD will become the largest hydropower plant in Africa, providing much needed electricity for the country’s growing population.

The project dams the Blue Nile, a river which later flows into neighbouring Sudan, where it merges with the White Nile and then flows on to Egypt. Like all rivers that flow across political boundaries, concerns have been raised about the equitable management of the water resources to the benefit of those upstream and down. Too much water dammed upstream in GERD could have negative effects on Egyptian agriculture reliant on river flows, for example. Efforts are ongoing to find a peaceful solution that suits all parties. Recently, suggestions have been made to supplement the dam’s power output with solar and wind to minimise disruption to the river’s users.

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Print Your Own Wireless 2.1 Speaker System

Buying a set of stylish bookshelf speakers is a perfectly reasonable thing to do, and remains legal in most free countries around the world. However, if you really want to impress with a pretty pair to crank out your tunes, you might consider designing and printing your own. [EH_Design] did just that with a stylish 2.1 Bluetooth audio system.

The 2.1 designation refers to the use of two stereo channels plus a subwoofer. It’s a popular setup as human perception means it’s not as necessary to have stereo imaging for low frequency content. The build uses a Texas Instruments TPA3116D2 Class D amplifier with a Bluetooth input, with the efficient design allowing the build to be more compact without the need for as much heat sinking. A 24 V supply delivering up to 3 A is specified, providing plenty of volume when needed. The speakers themselves consist of 3″ drivers mounted in attractive 3D-printed shells, with the “subwoofer” consisting of a pair of 5″ woofers paired up in a special isobaric enclosure that enables a smaller volume to acoustically act like one double the size.

The result is a futuristic-looking set of bookshelf speakers that remind us of some of the fancier high-end sets often seen in hi-fi magazines. Of course, if 3D printing enclosures isn’t enough for you, you could always consider 3D printing the actual speaker driver itself. When you do, let us know how it goes!

 

RC Ekranoplan Uses LIDAR To Fly In Ground Effect

Ekranoplans are a curious class of vehicle; most well known for several Soviet craft designed to operate at sea, flying just above the waves in ground effect. [rctestflight] had accidentally come across the ground effect flight regime himself years ago, and decided it was time to build an ekranoplan of his own.

I want to see little ekranoplans in at least three top 10 pop film clips by summer’s end. Please and thank you.

While ground-effect flight can be quite stable for a heavy, human-scale craft, the smaller RC version suffered more from minor perturbations from the wind and such. Thus, a Pixracer autopilot was installed, and combined with a small LIDAR device to accurately measure altitude above the ground. With some custom tweaks to the Ardupilot firmware, the craft was able to cleanly fly along barely a foot off the ground.

The final effect is almost mesmerizing; it appears as if the craft is hovering via some heretofore unknown technology rather than just flying in the usual sense. It’s still sensitive to breezes and sudden drops in the terrain lead to a temporary escape from the ground effect region, but the effect is nonetheless impressive. It’s a nerve wracking video at times, though, with quite a few near misses with traffic and children. Regardless of the nature of your experimental craft, be cognisant of your surroundings. We’ve seen [rctestflight]’s Ardupilot experiments before, too. Video after the break.

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