Portable Classroom Upgrade: Smaller, Cheaper, Faster

[Eric] at MkMe Lab has a dream: to build a cheap, portable system that provides the electronic infrastructure needed to educate kids anywhere in the world. He’s been working on the system for quite a while, and has recently managed to shrink the suitcase-sized system down to a cheaper, smaller form-factor.

The last time we discussed [Eric]’s EduCase project was as part of his Hackaday Prize 2016 entry. There was a lot of skepticism from our readers on the goals of the project, but whatever you think of [Eric]’s motivation, the fact remains that the build is pretty cool. The previous version of the EduCase relied on a Ku-band downlink to receive content from Outernet, and as such needed to stuff a large antenna into the box. That dictated a case in the carry-on luggage size range. The current EduCase is a much slimmed-down affair that relies on an L-band link from the Inmarsat satellites, with a much smaller patch antenna. A low-noise amp and SDR receiver complete the downlink, and a Raspberry Pi provides the UI. [Eric]’s build is just a prototype at this point, but we’re looking forward to seeing everything stuffed into that small Pelican case.

Yes, Outernet is curated content, and so it’s not at all the same experience as the web. But for the right use case, this little package might just do the job. And with a BOM that rings up at $100, the price is right for experimenting.

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FTA dish used to receive L-band amateur radio

[David Prutchi] has an FTA (free-to-air) satellite dish. This means he can tune and watch freely available satellite television feeds. But this sounds much better than it actually is. There isn’t much that’s broadcasted unecrypted from satellites with the exception of a collection of religious channels. But he still uses the dish by using the FTA satellites to calibrate the alignment, then repositioning it to receive L-Band radio transmissions with his own add-on hardware. In the image above it’s the spiral of wire attached to the dish’s collector.

The satellite transmissions are picked up on the KU-band by an aftermarket horn that [David] purchased for this purpose. To add his own helix receiver he cut a square mounting plate that fits around the horn. This plate serves as a reflector and ground plane, and also hosts the helix connector which picks up the L-band transmissions. He had to be creative with routing the first few inches of the helix but it looks like he manages to get some pretty good performance out of the hardware.

[via Hacked Gadgets]