Adding 3D Printer Power And Light Control To OctoPrint

September 15, 2018 by Tom Nardi 15 Comments

OctoPrint is a great way to monitor your printer, especially with the addition of a webcam. Using a tablet or mobile phone, you can keep an eye on what the printer is doing from anywhere in the house (or world, if you take the proper precautions), saving you from having to sit with the printer as if it’s an infant. But simply watching your printer do its thing is only a small slice of the functionality offered by OctoPrint’s vast plugin community.

As [Jeremy S Cook] demonstrates, it’s fairly easy to add power control for the printer and auxiliary lighting to your OctoPrint setup. Being able to flick the lights on over the print bed is obviously a big help when monitoring it via webcam, and the ability to turn the printer off can provide some peace of mind after the print has completed. If you’re particularly brave it also means you could power on the printer and start a print completely remotely, but good luck if that first layer doesn’t go down perfectly.

In terms of hardware, you only need some 3.3V relays for the Raspberry Pi running OctoPrint to trigger, and an enclosure to put the wiring in. [Jeremy] uses only one relay in this setup to power the printer and lights at once, but with some adjustment to the software, you could get independent control if that’s something you’re after.

On the software side [Jeremy] is using an OctoPrint plugin called “PSU Control”, which is actually intended for controlling an ATX PSU from the Pi’s GPIO pins, but the principle is close enough to throw a relay. Other plugins exist which allow for controlling a wider away of devices and GPIO pins if you want to make a fully remote controlled enclosure. Plus you can always whip up your own OctoPrint plugin if you don’t find anything that quite meets your switching needs.

[Jeremy] previously documented his unique mount to keep his Raspberry Pi and camera pointed at his printer, which is naturally important if you want to create some cool videos with Octolapse.

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Researcher uses antenna to clone Tesla key fob

Tesla Opens With Precomputed Key Fob Attack

September 13, 2018 by Jonathan Bennett 43 Comments

This clever precomputation attack was developed by a group of researchers at KU Leuven in Belgium. Unlike previous key fob attacks that we’ve covered in the past which have been essentially relay attacks, this hack precomputes a ton of data, looks for a collision in the dataset, and opens the door. Here’s how it works.

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No Signal For Your Radio-Controlled Watch? Just Make Your Own Transmitter

September 10, 2018 by Ben James 37 Comments

You can win any argument about the time when you have a radio controlled watch. Or, at least, you can if there’s any signal. [Henner Zeller] lives in a place where there is no reception of the DCF77 signal that his European wristwatch expects to receive. Consequently, he decided to make his own tiny transmitter, which emulates the DCF77 signal and allows the watch to synchronise.

A Raspberry Pi Zero W is the heart of the transmitter, and [Henner] manages to coax it into generating 77500.003Hz on a GPIO pin – close enough to the 77.5kHz carrier that DCF77 uses. The signal is AM, and transmits one bit/s, repeating every minute. A second GPIO performs the required attenuation, and a few loops of wire are sufficient for an antenna which only needs to work over a few inches. The Raspberry Pi syncs with NTP Stratum 1 servers, which gives the system time an accuracy of about ±50ms. The whole thing sits in a slick 3D printed case, which provides a stand for the watch to rest on at night; this means that every morning it’s synchronised and ready to go.

[Henner] also kindly took the time to implement the protocols for WWVB (US), MSF (UK) and JJY (Japan). This might be just as well, given that we recently wrote about the possibility of WWVB being switched off. Be sure to check the rules in your area before giving this a try.

We’ve seen WWVB emulators before, like this ATtiny45 build, but we love that this solution is an easy command line tool which supports many geographical locations.

Don’t Look Now, But Your Necklace Is Listening

September 7, 2018 by Tom Nardi 9 Comments

There was a time when the average person was worried about the government or big corporations listening in on their every word. It was a quaint era, full of whimsy and superstition. Today, a good deal of us are paying for the privilege to have constantly listening microphones in multiple rooms of our house, largely so we can avoid having to use our hands to turn the lights on and off. Amazing what a couple years and a strong advertising push can do.

So if we’re going to be funneling everything we say to one or more of our corporate overlords anyway, why not make it fun? For example, check out this speech-to-image necklace developed by [Stephanie Nemeth]. As you speak, the necklace listens in and finds (usually) relevant images to display. Conceptually this could be used as an assistive communication technology, but we’re cool with it being a meme display device for now.

Hardware wise, the necklace is just a Raspberry Pi 3, a USB microphone, and a HyperPixel 4.0 touch screen. The Pi Zero would arguably be the better choice for hanging around your neck, but [Stephanie] notes that there’s some compatibility issues with Node.js on the Zero’s ARM6 processor. She details a workaround, but says there’s no guarantee it will work with her code.

The JavaScript software records audio from the microphone with SoX, and then runs that through the Google Cloud Speech-to-Text service to figure out what the wearer is saying. Finally it does a Google image search on the captured words using the custom search JSON API to find pictures to show on the display. There’s a user-supplied list of words to ignore so it doesn’t try looking up images for function words (such as “and” or “however”), though presumably it can also be used to blacklist certain imagery you might not want popping up on your chest in mixed company.

We’d be interested in seeing somebody implement this software on a Raspberry Pi powered digital frame to display artwork that changes based on what the people in the room are talking about. Like in Antitrust, but without Tim Robbins offing anyone.

Retro Console Upgrade Gives Atari Flair

September 5, 2018 by Bryan Cockfield 3 Comments

If you’re desperate for a sense of nostalgia for video games of yore but don’t want to shell out the big bucks for an NES classic, you can always grab a single arcade-style game that’ll plug straight into your TV. Of course it’s no longer 1980, and playing Space Invaders or Asteroids can get old after a while. When that happens, just replace the internals for an upgraded retro Atari 2600 with all the games from that system instead of just one.

As expected for something that has to fit in such a tiny package, this upgrade is based on a Raspberry Pi Zero. It’s not quite as simple as throwing RetroPi on it and calling it a day, though. For one, [Blue Okiris] is still using the original two-button controller/joystick that came with the Ms. Pac-Man game this build is based on, and that added its own set of challenges. For another, RetroPi didn’t have everything he needed so he switched to another OS called Recalbox. It also includes Kodi so it could be used as a media center as well.

The build looks like a hack in the truest sense of the word. The circuit board sticks out the bottom a little bit, but this is more of a feature than a bug because that’s where some extra buttons and the power switch are. Overall, it’s a great Retro Atari system that has all the true classics that should keep [Blue Okiris] entertained until Atari releases an official system one day. If you’d like to go a little deeper in the Atari world, though, you could always restore one instead.

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Monitoring blinking LED for home power usage

Monitoring Power By Counting Blinks

September 5, 2018 by Steven Dufresne 14 Comments

What do you do when you want to add a new feature to some electronics but you can’t or don’t want to tear into the guts? You look for something external with which you can interface. We like these hacks because they take some thinking outside the box, literally and figuratively, and often involve an Aha! moment.

[Simon Aubury’s] big household load was electric heating and his ancient heaters didn’t provide any way to monitor their usage. His power meters weren’t smart meters and he didn’t want to open them up. But the power meters did have an external LED which blinked each time 1 Wh was consumed. Aha! He could monitor the blinks.

Home power usage graph — Maximum is white, average is orange, and minimum is blue.

Doing so was simple enough. Just point photoresistors at the two meter’s LEDs and connect them and capacitors to a Raspberry Pi’s GPIO pins. Every time a pulse is detected, his Python code increments the LED’s counter and every fifteen minutes he writes the counters to an SQL database. Analysing his data he saw that nothing much happens before 5 AM and that the lowest daytime usage is around noon. The maximum recorded value was due to a heater accidentally being left on and the minimum is due to a mini holiday. Pretty good info given that all he had to go on was a blinking light.

Where else are there LED indicators which you can tap into? Here’s an only slightly more invasive usage where a washing machine’s “end of cycle” LED was removed and the power going to it was rerouted to an Arduino for remote monitoring.

This Is The Raspberry Pi Robot To Beat All Others

August 29, 2018 by Brian Benchoff 13 Comments

Before the introduction of the Raspberry Pi, building robots was hard. The best solution to turning motors on a chassis was repurposing an old roomba. For the brain, maybe you could throw Linux on a router and move your rover around with an old Linksys. Before that, you could buy a crappy robotics kit, thrown together in a box and sold as an ‘educational kit’. I’m sure there are a few readers out there that built robots by wire-wrapping HC11s.

Now we have 3D printers and Raspberry Pis, and with that comes a golden age of robotics. One of the best robot brains out there is the 8BitRobots Modules from [Tim Wilkinson], an entry for this year’s Hackaday Prize.

The 8BitRobots Modules are made up of a few components, not the least of which is a Pi Zero, a fantastically powerful (for its price) Linux computer that is available for five dollars. With an add-on board, cleverly named the RoBonnet, the Pi Zero gets PWM outputs for servos and ESCs, an H-bridge for motors, TTL serial, encoder inputs, a pressure and temperature sensor, an IMU, a power monitor, and everything else you need for a successful Pi robot.

But hardware is only one part of the equation. If you want to program a robot, you need a software stack that makes everything easy. That’s where the 8BitRobots distributed robot platform comes in. This is a bit of Javascript running on the Pi that allows you to program the robot in Blockly, a Scratch-like graphical programming environment that’s been adapted to run in a web browser. It’s an all-in-one solution to robotics development and programming, and an excellent addition to this year’s Hackaday Prize.