Portable Classroom Upgrade: Smaller, Cheaper, Faster

November 20, 2016 by 7 Comments

[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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Five-Watt SDR Transceiver For Hams

November 20, 2016 by 50 Comments

The availability of cheap SDR hardware created a flourishing ecosystem for SDR software, but a lot of the hardware driving the revolution was still “cheap”. In the last few years, we’ve seen quality gear replacing the TV dongles in many setups, and down-converters designed for them to allow them to work on the ham bands.

But something that’s purpose-built might be a better option if ham radio, particularly the shortwave portion thereof, is your goal. First off, you might want to transmit, which none of the TV dongles allow. Then, you might want a bit of power. Finally, if you’re serious about short-wave, you care more about the audio quality than you do immense bandwidth, so you’re going to want some good filters on the receiving end to help you pull the signal out of all the noise.

rs-hfiq_block_diagram_featuredThe RS-HFIQ 5 W SDR transceiver might be for you. It’s up on Kickstarter right now, and it’s worth looking at if you want a fully open source (schematics, firmware, and software) shortwave SDR rig. It’s also compatible with various open frontends.

The single-board radio isn’t really a full SDR in our mind — it demodulates the radio signal and sends a 96 kHz IQ signal across to your computer’s soundcard where it gets sampled and fully decoded. The advantage of this is that purpose-built audio rate DACs have comparatively high resolution for the money, but the disadvantage is that you’re limited to 96 kHz of spectrum into the computer. That’s great for voice and code transmissions, but won’t cut it for high-bandwidth data or frequency hopping applications. But that’s a reasonable design tradeoff for a shortwave.

Still, an SDR like this is a far cry from how simple a shortwave radio can be. But if you’re looking to build up your own SDR-based shortwave setup, and you’d like to hack on the controls more than on the radio itself, this looks like a good start.

Make Your Eyes Louder With Bluetooth Speaker Goggles

November 20, 2016 by 16 Comments

Your eyes are cool, but they aren’t very loud. You can remedy that with this build from [Sam Freeman]: a pair of Bluetooth speaker goggles. Combine a pair of old welders goggles with a Bluetooth receiver, a small amp and a couple of cheap speaker drivers and you’re well on your way to securing your own jet set radio future.

[Sam] found a set of speaker drivers that were the same size as the lenses of the goggles, as if they were designed for each other. They don’t do much for your vision, but they definitely look cool. [Sam] found that he could run the speakers for an hour or so from a small Lithium Ion battery that’s hidden inside the goggles, along with a large lever switch for that throwback electronics feel. The total cost of this build is a reasonably-low at $40, or less if you use bits from your junk pile.

The real trick is watching them in action and deciding if there’s any motion happening. Don’t get us wrong, they look spectacular but don’t have the visual feedback component of, say, the bass cannon. Look for yourself in the clip below. We might add a pair of googly eyes on the speakers that dance as they move, but that would get away from the more serious Robopunk look that [Sam] is going for. What would you add to build up the aesthetic of these already iconic goggles?

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Jenkins And Slack Report Build Failure! Light The Beacons!

November 19, 2016 by 10 Comments

When you have a large software development team working on a project, monitoring the build server is an important part of the process. When a message comes in from your build servers, you need to take time away from what you’re doing to make sure the build’s not broken and, if it’s broken because of something you did, you have to stop what you’re doing, start fixing it and let people know that you’re on it.

[ridingintraffic]’s team uses Jenkins to automatically build their project and if there’s a problem, it sends a message to a Slack channel. This means the team needs to be monitoring the Slack channel, which can lead to some delays. [ridingintraffic] wanted immediate knowledge of a build problem, so with some software, IoT hardware, and a rotating hazard warning light, the team now gets a visible message that there’s a build problem.

An Adafruit Huzzah ESP8266 board is used as the controller, connected to some RF controlled power outlets via a 434MHz radio module. To prototype the system, [ridingintraffic] used an Arduino hooked up to one of the RF modules to sniff out the codes for turning the power outlets on and off from their remotes. With the codes in hand, work on the Huzzah board began.

An MQTT broker is used to let the Huzzah know when there’s been a build failure. If there is, the Huzzah turns the light beacon on via the power outlets. A bot running on the Slack channel listens for a message from one of the developers saying that problem is being worked on, and when it gets it, it sends the MQTT broker a message to turn the beacon off.

There’s also some separation between the internal network, the Huzzahs, and the Slack server on the internet, and [ridingintraffic] goes over the methods used to communicate between the layers in a more detailed blog post. Now, the developers in [ridingintraffic]’s office don’t need to be glued to the Slack channel, they will not miss the beacon when it signals to start panicking!

Stairwell Lights Keep Toddler With Night-Blindness Safe

November 19, 2016 by 25 Comments

A devastating diagnosis for a young child is every parent’s worst nightmare. All too often there’s nothing that can be done, but occasionally there’s a window of opportunity to make things better for the child, even if we can’t offer a cure. In that case even a simple hack, like a rapid response stairwell light to help deal with night-blindness, can make a real difference.

[Becca] isn’t yet a year old, but she and her parents carry a heavy burden. She was born with Usher Syndrome, an extremely rare genetic disease that affects hearing and vision to different degrees. In [Becca]’s case, she was born profoundly deaf and will likely lose her sight by the time she’s 10 or so. Her dad [Jake] realized that the soon-to-be-toddler was at risk due to a dark stairwell and the night-blindness that accompanies Usher, so he came up with a simple tech solution to the problem.

He chose Philips Hue LED light strips to run up the stringer of the stairs controlled by a Raspberry Pi. Originally he planned to use IFTTT for the job but the latency resulted in the light not switching on fast enough. He ended up using a simple PIR motion sensor which the Pi monitors and then uses the Hue API to control the light. This will no doubt give him a platform for future capabilities to help [Becca].

We’ve covered a few builds where parents have hacked solutions for their kids, like this custom media center for the builder’s autistic son. We suspect [Jake] has a few more tricks up his sleeve to help [Becca], and we’re looking forward to seeing how she does.

Ruggedizing A Cheap Camera For Spacecraft Testing

November 19, 2016 by 13 Comments

Name the countries that house a manned space program. In order of arrival in space, USSR/Russian Federation, United States of America, People’s Republic of China. And maybe one day, Denmark. OK, not the Danish government. But that doesn’t stop the country having a manned space program, in the form of Copenhagen Suborbitals. As the tagline on their website has it: “We’re 50 geeks building and flying our own rockets. One of us will fly into space“. If that doesn’t catch the attention of Hackaday readers, nothing will.

For their rocket testing they need a lot of video feeds, and for that they use cheap Chinese GoPro clones. The problem with these (and we suspect many other cameras) is that when subjected to the temperature and vibration of being strapped to a rocket, they cease to work. And since even nonprofit spaceflight engineers are experts at solving problems, they’ve ruggedized the cameras to protect them from vibration and provide adequate heatsinking.

The heat issue is addressed by removing the camera case and attaching its metal chassis directly to a heatsink that forms the end of an extruded aluminium case. Vibration was causing the camera SD cards to come loose, so these are soldered into their sockets. Power is provided by a pair of 18650 cells with a switching regulator to provide internal power, and another to allow the unit to be charged from a wide range of input voltages. A PCB houses both the regulators and sockets for cable distribution. There is even a socket on top of the case to allow a small monitor to be mounted as a viewfinder. Along the way they’ve created a ruggedized camera that we think could have many applications far beyond rocket testing. Maybe they should sell kits!

We’ve covered Copenhagen Suborbitals before quite a few times, from their earliest news back in 2010, through a look at their liquid-fueled engine, to a recent successful rocket launch. We want to eventually report on this project achieving its aim.

Thanks [Morten] for the tip.

Under The (Linux) Hood

November 19, 2016 by 53 Comments

We’ve often heard that you don’t need to know how an engine works to drive a car, but you can bet that professional race car drivers know. By analogy, you can build lots of systems with off-the-shelf boards like Raspberry Pis and program that using Python or some other high-level abstraction. The most competent hackers, though, know what’s going on inside that Pi and what Python is doing under the hood down to some low level.

If you’ve been using Linux “under the hood” often means understanding what happens inside the kernel–the heart of the Linux OS that manages and controls everything. It can be a bit daunting; the kernel is simple in concept, but has grown over the years and is now a big chunk of software to approach.

Your first embedded system project probably shouldn’t be a real time 3D gamma ray scanner. A blinking LED is a better start. If you are approaching the kernel, you need a similar entry level project. [Stephen Brennan] has just the project for you: add your own system call to a custom Linux kernel.

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