raspberry pi

1631 Articles

Password-Free Guest WiFi From Raspberry Pi

December 19, 2016 by 31 Comments

Anytime you’re having more than a handful of people over to your place for a wild rager or LAN party (or both), you’ll generally need a way to make sure everyone can get their devices on the network. Normally, this would involve either putting your WiFi password into more phones than you can count or yelling your password across a crowded room. Neither of these options suited [NicoHood] and his partner, however, so he came up with another more secure solution to the WiFi-in-a-crowded-room problem.

He calls his project “guestwlan” and it’s set up to run on a Raspberry Pi with a touch screen. When a potential WiFi user approaches the Pi and requests access to the network, the Pi displays a QR code. Within that code is all of the information that the prospective device needs to connect to the network. For those who have already spotted the new security vulnerability that this creates, [NicoHood] has his guest WiFi on a separate local network just to make sure that even if someone nefarious can access the Internet, it would be more difficult for them to do anything damaging to his local network. As it stands, though, it’s a lot more secure than some other WiFi networks we’ve seen.

[NicoHood] also released his software on Git but it has been configured for use with Arch. He says that it would probably work in a Debian environment (which the Raspberry Pi-specific OS is based on) but this is currently untested. Feel free to give it a try and let us know how it goes.

LED Tetris Table

December 18, 2016 by 7 Comments

No hackspace is complete without an arcade game project or two. Usually these projects are time-worn generic cabinets scarred by the frustrated kicks of a million teenagers, the decades-old Japanese CRT monitors inside of which are ready to shuffle off this mortal coil. You are lucky if you catch them on a rare moment of functioning, and their owners are always hovering ready to attend to any soon-to-expire electronics.

York Hackspace have done things a little differently though. Their member [John] has an arcade game project, but instead of an aged cabinet he’s produced his own tabletop game with an array of multicolour addressable LED strips powered by a Raspberry Pi. Each LED sits in its own foam cell under the translucent surface, so it forms a low resolution color block display.

It’s a Tetris game in its first incarnation, but there is also a copy of Snake underway for it. If it catches your attention you can write your own games, because all its resources are available in a GitHub repository.

This is one of many Tetris interfaces we’ve seen over the years. Largest was probably this skyscraper, but this oscilloscope version is particularly well-executed. One of our most recent forays into Tetris-land though is also one of the most technically interesting, a 446-byte implementation in a master boot record.

Raspberry Pi Zero smart projector

Smart Projector With Built-in Raspberry Pi Zero

December 18, 2016 by 16 Comments

You’ve heard of smartphones but have you heard of smart projectors? They’ve actually been around for a few years and are sort of like a TV set top box and projector combined, leaving no need for a TV. Features can include things like streaming Netflix, browsing in Chrome, and Skyping. However, they can cost from a few hundred to over a thousand dollars.

[Novaspirit]  instead made his own cheap smart projector. He first got a $70 portable projector (800×480 native resolution, decent for that price) and opened it up. He soldered an old USB hub that he already had to a Raspberry Pi Zero so that he could plug in a WiFi dongle and a dongle for a Bluetooth keyboard. That all went into the projector.

Examining the projector’s circuit board he found locations to which he could wire the Raspberry Pi Zero for power even when the projector was off. He lastly made the Raspberry Pi dual-bootable into either OSMC or RetroPie. OSMC is a Linux install that boots directly into a media player and RetroPie is a similar install that turns your Raspberry Pi into a gaming machine. You can see a timelapse of the making of it and a demonstration in the video after the break.

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High-Quality Film Transfers With This Raspberry Pi Frame Grabber

December 15, 2016 by 19 Comments

Untold miles of film were shot by amateur filmmakers in the days before YouTube, iPhones, and even the lowly VHS camcorder. A lot of that footage remains to be discovered in attics and on the top shelves of closets, and when you find that trove of precious family memories, you’ll be glad to have this Raspberry Pi enabled frame-by-frame film digitizer at your disposal.

With a spare Super 8mm projector and a Raspberry Pi sitting around, [Joe Herman] figured he had the makings of a good way to preserve his grandfather’s old films. The secret of high-quality film transfers is a frame-by-frame capture, so [Joe] set about a thorough gutting of the projector. The original motor was scrapped in favor of one with better speed control, a magnet and reed switch were added to the driveshaft to synchronize exposures with each frame, and the optics were reversed with the Pi’s camera mounted internally and the LED light source on the outside. To deal with the high dynamic range of the source material, [Joe] wrote Python scripts to capture each frame at multiple exposures and combine the images with OpenCV. Everything is stitched together later with FFmpeg, and the results are pretty stunning if the video below is any indication.

We saw a similar frame-by-frame grabber build a few years ago, but [Joe]’s setup is nicely integrated into the old projector, and really seems to be doing the job — half a million frames of family history and counting.

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Hybrid Raspberry Pi + PIC32 = Oscilloscope And Function Generator

December 13, 2016 by 18 Comments

The PicBerry is a student final project by [Advitya], [Jeff], and [Danna] that takes a hybrid approach to creating a portable (and affordable) combination digital oscilloscope and function generator. It’s based on the Raspberry Pi, features an intuitive Python GUI, and can generate and measure simultaneously.

But wait! The Raspberry Pi is a capable little Linux machine, but meeting real-time deadlines isn’t its strong suit. That’s where the hybrid approach comes in. The Pi takes care of the user interface and other goodies, and a PIC32 over SPI is used for 1 MHz sampling and running a DAC at 500 kHz. The idea of combining them into PicBerry is to get the best of both worlds, with the Pi and PIC32 each doing what they are best at. The readings are sent in batches from the PIC32 to the Pi, where the plot is updated every 30 ms so that user does not perceive any visible lag.

The project documentation notes that improvements can be made, the speeds are a far cry from regular bench equipment, and the software lacks some typical features such as triggering, but overall not bad at all for under $50 of parts. In fact, there are hardly any components at all beyond the Raspberry Pi, the PIC32, and a MCP4822 digital-to-analog converter. A short demo video is embedded below.

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The Nest: Album Release Hidden In A Rock

December 11, 2016 by 31 Comments

First there were vinyl records, then came cassettes, CDs, those failed audio-on-DVD formats, and then downloads. To quote the band, [Bateleur], “you can’t pay someone to take a CD these days.” So how do you release your new album? By hiding a Raspberry Pi in a semi-transparent fake rock on a mountainous cliff, and requiring a secret whistle to enable it, naturally.

Once activated, you’ll be able to plug into the USB port and download the album, or sit there on a remote hillside cliff overlooking the ocean and enjoy the new tunes. Because there’s a headphone jack in the rock, naturally. Besides being a cool hack, we think that putting people in the right physical and mental space for a serious listening is brilliant. Watch the video embedded below for an idea of the making of and a view from the site.

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Homebrew Dash Cam Enables Full Suite Of Sensors

December 6, 2016 by 21 Comments

You heard it here first: dash cams are going to be the next must-have item for your daily driver. Already reaching market saturation in some parts of the world but still fairly uncommon in North America, we predict that car makers will soon latch onto the trend and start equipping cars with dash cams as standard equipment. And you can just bet that whatever watered-down, overpriced feature set they come up with will be sure to disappoint, so you might want to think about building your own Raspberry Pi dash cam with an accelerometer and lots of LEDS.

Still very much in the prototyping phase, [CFLanger]’s project is at its heart a dash cam, but it looks like he wants to go far beyond that. Raspivid and a PI NoIR camera take care of the video streaming, but the addition of a Pi SenseHAT gives [CFLanger] a bunch of options for sensing and recording the car’s environment. Not content with the SenseHAT’s onboard accelerometer, he added an ADXL345 to the sensor suite. The 64-pixel LED display is just for fun – it displays pitch and roll of the platform – and a yet-to-be-implemented bar-graph display will show acceleration in the X-axis. He figures the whole thing is good for a couple of days of video, but we hope he adds audio capture and perhaps ECU data from an OBDII-Bluetooth adapter.

We’ve seen surprisingly few DIY dash cams on Hackaday, at least so far. There has been a dash cam teardown and retasking, and there are plenty of dashboard computer builds, though. Seems like most hackers want that DIY self-driving car first.

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