Hack My House: ZoneMinder’s Keeping An Eye On The Place

October 23, 2018 by 53 Comments

Hacks are often born out of unfortunate circumstances. My unfortunate circumstance was a robbery– the back door of the remodel was kicked in, and a generator was carted off. Once the police report was filed and the door screwed shut, it was time to order cameras. Oh, and record the models and serial numbers of all my tools.

We’re going to use Power over Ethernet (POE) network cameras and a ZoneMinder install. ZoneMinder has a network trigger capability, and we’ll wire some magnetic switches to our network of PXE booting Pis, using those to inform the Zoneminder server of door opening events. Beyond that, many newer cameras support the Open Network Video Interface Forum (ONVIF) protocol and can do onboard motion detection. We’ll use the same script, running on the Pi, to forward those events as well.

Many of you have pointed out that Zoneminder isn’t the only option for open source camera management. MotionEyeOS, Pikrellcam, and Shinobi are all valid options.  I’m most familiar with Zoneminder, even interviewing them on FLOSS Weekly, so that’s what I’m using.  Perhaps at some point we can revisit this decision, and compare the existing video surveillance systems.

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Slack On The SNES Via Satellite

October 23, 2018 by 14 Comments

We love seeing hardware and software from bygone eras getting a new lease on life through modern hacks, as longtime readers can surely attest to. Why leave this stuff to rot in a closet somewhere when it can be pushed into service today? Granted it might not always be the most efficient way to accomplish a task in the 21st century, but at least you’ll net some precious Internet Points for originality.

As a perfect example, take a look at this project which lets you read Slack messages through a Super Nintendo game. If your first thought was that such a thing would involve an unreasonable amount of effort and hoop jumping…then you would be correct. [Bertrand Fan] really had to think outside the box to make this one happen, and even admits a bit of imagination is required on the part of the end-user to use it. But it’s undeniably an original approach, so we hereby bestow the customary Internet Points unto him.

So how does this work, and where do the satellites come in? The key is in a fairly obscure Japanese SNES peripheral called the Satellaview, one of Nintendo’s early attempts at creating an online content delivery system for their consoles. Games designed with Satellaview support would be able to pull down new content from regular satellite broadcasts, not too bad for 1995. This means that if you have the hardware, and happen to own a satellite, you can push your own content into an unmodified SNES. No problem, right?

Alright, [Bertrand] didn’t really use a Satellaview modem plugged into an actual SNES. Plus we’re fairly sure he doesn’t have his own satellite network to broadcast Slack messages with anyway. But it turns out some SNES emulators have support for a virtual Satellaview modem, and there’s even software out there that will let you create new content “downloads” for the system’s included game: BS-X: The Story of The Town Whose Name Was Stolen. All he had to do was connect the dots.

[Bertrand] started by stripping the user interface out of SatellaWave, an open source tool for creating Satellaview content, so that it only need to be provided with an XML file of the content to be “downloaded” by the virtual satellite modem. Using the Slack API, he then came up with way to pull the last 10 messages from a server and push them into his modified version of SatellaWave. Each time somebody posts a new message his software kicks in to produce a new satellite download which automatically gets picked up by the SNES emulator and pops up in the game.

If this is still too practical for you, you can always go all in and run Slack on your Commodore 64.

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$3 Multimeter Teardown

October 23, 2018 by 44 Comments

[Diode Gone Wild] and his cat decided to see how a $3 meter worked inside. The meter was marked as a DT-830B and he already had an older one of the same model, and he wondered how they could afford to sell it — including shipping — for $3. You can see a video of his testing, teardown, and reverse engineering below.

What was odd is that despite having the same model number, the size of the meter was a bit different. When he opened the case to install a battery, he noticed the board didn’t look like it had fuses or components appropriate for the rated voltages. He decided the missing parts might be under the board and tested the meter.

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Real Time Satellite Tracker Shows You What’s Going Over Your Head

October 22, 2018 by 9 Comments

Whilst modern technology relies heavily on satellites, it’s easy to forget they’re there; after all, it’s hard to comprehend mostly-invisible lumps of high-density tech whizzing around above you at ludicrous speeds. Of course, it’s not hard to comprehend if you’ve built a real-time satellite tracker which displays exactly what’s in orbit above your head at any given time. [Paul Klinger]’s creation shows the position of satellites passing through a cylinder of 200 km radius above the tracker.

Each layer of LEDs represents a specific band of altitude, whilst the colour of the LEDs and text on the screen represent the type of object. The LEDs themselves are good old WS2812b modules, soldered to a custom PCB and mounted in a 3D-printed stand. The whole thing is a really clean build and looks great – you can see it in action in the video after the break

On the software side, a Raspberry Pi is in charge, running Python which makes use of pyorbital for some of the heavy lifting. The data is taken from space-track.org, who provide a handy API. All the code is on the project GitHub, which also includes the 3D print and PCB files.

[Paul] answers questions in the reddit thread, and gives more detail in this reddit comment. The project was inspired by one of our favorite sites: stuffin.space.

Some of the satellites the device displays are de-commisioned and inactive. Space junk is a significant problem, one which can only be tackled by a space garbage truck.

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Jump Into AI With A Neural Network Of Your Own

October 22, 2018 by 6 Comments

One of the difficulties in learning about neural networks is finding a problem that is complex enough to be instructive but not so complex as to impede learning. [ThomasNield] had an idea: Create a neural network to learn if you should put a light or dark font on a particular colored background. He has a great video explaining it all (see below) and code in Kotlin.

[Thomas] is very interested in optimization, so his approach is very much based on mathematics and algorithms of optimization. One thing that’s handy is that there is already an algorithm for making this determination. He found it on Stack Exchange, but we’re sure it’s in a textbook or paper somewhere. The existing algorithm makes the neural network really impractical, but it makes training easy since you can algorithmically develop a training set of data.

Once trained, the neural network works well. He wrote a small GUI and you can even select among various models.

Don’t let the Kotlin put you off. It is a derivative of Java and uses the same JVM. The code is very similar, other than it infers types and also adds functional program tools. However, the libraries and the principles employed will work with Java and, in many cases, the concepts will apply no matter what you are doing.

If you want to hardware accelerate your neural networks, there’s a stick for that. If you prefer C and you want something lean and mean, try TINN.

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Wave-Powered Glider Delivers Your Message In A Bottle

October 22, 2018 by 9 Comments

Setting a bottle adrift with a message in it is, by most measures, an act of desperation. The sea regularly swats mighty ships to their doom, so what chance would a tiny glass bottle have bobbing along the surface, subject as it is to wind, waves, and current? Little to none, it would seem, unless you skew the odds a bit with a wave-powered undersea glider to the help the bottle along.

Before anyone gets too worked up about this, [Rulof Maker]’s “Sea Glider” is about a low-tech as a device with moving parts can be. This craft, built from a scrap of teak and a busted wooden ruler, is something that could be assembled in a few hours from whatever you have on hand, even if you’re marooned on an uncharted desert isle. The body of the craft sprouts a set of horizontal planes that can swivel up and down independently. The key to providing a modicum of thrust is that each plane is limited to a 90° swing by stop blocks above and below the pivot. The weighted glider, tethered to the bottle, bobs up and down below the waves, flapping the planes and providing a tiny bit of thrust.

Was it enough to propel the bottle any great distance? We won’t ruin the surprise, but we will say that [Rulof]’s essentially zero-cost build appears to have improved the message in a bottle bandwidth at least somewhat. It’s not a Hackaday Prize-winning robotic sea glider, but it’s a neat hack nonetheless.

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Robot + Trumpet = Sad Trombone.mp3

October 22, 2018 by 13 Comments

[Uri Shaked] is really into Latin music. When his interest crescendoed, he bought a trumpet in order to make some energetic tunes of his own. His enthusiasm flagged a bit when he realized just how hard it is to get reliably trumpet-like sounds out of the thing, but he wasn’t about to give up altogether. Geekcon 2018 was approaching, so he thought, why not make a robot that can play the trumpet for me?

He scoured the internet and found that someone else had taken pains 20 years ago to imitate embouchure with a pair of latex lips (think rubber glove fingers filled with water). Another soul had written about measuring air flow with regard to brass instruments. Armed with this info, [Uri] and partners [Ariella] and [Avi] spent a few hours messing around with air pumps, latex, and water and came up with a proof of concept that sounds like—and [Uri]’s description is spot-on—a broken robotic didgeridoo. It worked, but the sound was choppy.

Fast forward to Geekcon. In a flash of brilliance, [Avi] thought to add capacitance to the equation. He suggested that they use a plastic box as a buffer for air, and it worked. [Ariella] 3D printed some fingers to actuate the valves, but the team ultimately ended up with wooden fingers driven by servos. The robo-trumpet setup lasted just long enough to get a video, and then a servo promptly burned out. Wah wahhhh. Purse your lips and check it out after the break.

If [Uri] ever gets fed up with the thing, he could always turn it into a game controller a la Trumpet Hero.

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