raspberry pi

1627 Articles

Simple RFID Door Lock System

September 25, 2016 by 23 Comments

Group entry hacks are a favorite for hacker social groups. Why use old fashioned keys when you can use newfangled electronic keys? If you are looking to build a simple RFID-based security system to secure your important stuff, this project from Resin.io is a good place to start. In it, [Joe Roberts] outlines the process of building a simple RFID-triggered mechanism for their office door.

It’s a pretty simple setup that is composed of an RFID reader, a Rasperry Pi and a Neopixel ring. When someone places an RFID card against the reader hidden behind a poster by their front door, the reader grabs the code and the Pi compares it with a list of authorized users. If the card is on the list, the Pi triggers the door lock using a signal line originally designed to work with an intercom system. If the user isn’t on the list, a laser is triggered that vaporizes the interloper… well, that’s perhaps in the next version, along with an API that will allow someone to open the door from the company chat application.

At the moment, this is a clean, simple build that uses only a few cheap components, but which could be the basis for a more sophisticated security system in the future.

Hackaday Links: September 25, 2016

September 25, 2016 by 21 Comments

So you like watching stupid stuff? Here you go, a scene from Bones that tops the infamous ‘IP backtrace with Visual Basic’ or ‘four-handed keyboard’ scenes from other TV shows. Someone hacked the bones by embedding malware in a calcium fractal pattern. Also, when she uses the fire extinguisher, she doesn’t spray the base of the fire.

Raspberry Pi! You have no idea how good the term Raspberry Pi is for SEO. Even better is Raspberry Pi clusters, preferably made with Raspberry Pi Zeros. Here’s a Raspberry Pi hat for four Raspberry Pi Zeros, turning five Raspberry Pis into a complete cluster computer. To be honest and fair, if you’re looking to experiment with clusters, this probably isn’t a bad idea. The ‘cluster backplane’ is just a $2 USB hub chip, and a few MOSFETs for turning the individual Pis on and off. The Zeros are five bucks a pop, making the entire cluster cost less than two of the big-boy sized Pi 3s.

Do you think you might have too much faith in humanity? Don’t worry, this video has you covered.

Hacking on some Lattice chips? Here’s a trip to CES for you. Lattice is holding a ‘hackathon’ for anyone who is building something with their chips. The top prize is $5k, and a trip to next year’s CES in Vegas, while the top three projects just get the trip to Vegas. If you already have a project on your bench with a Lattice chip, it sounds like a great way to wait an hour for a cab at McCarran.

UPSat. What’s an upsat? Not much, how about you? The first completely open source hardware and software satellite will soon be delivered to the ISS. Built by engineers from the University of Patras and the Libre Space Foundation, the UPSat was recently delivered to Orbital ATK where it will be delivered to the ISS by a Cygnus spacecraft. From there, it will be thrown out the airlock via the NanoRacks deployment pod.

The Voyager Golden Record is a message in a bottle thrown into the cosmic ocean and a time capsule from Earth that may never be opened. Now it’s a Kickstarter. Yes, this record is effectively Now That’s What I Call Humanity volume 1, but there are some interesting technical considerations to the Voyager Golden Record. To the best of my knowledge, no one has ever tried to extract the audio and pictures from this phonographic time capsule. The pictures included in the Golden Record are especially weird, with the ‘how to decode this’ message showing something like NTSC, without a color burst, displayed on a monitor that is effectively rotated 90 degrees counterclockwise from a normal CRT TV. Want to know how to get on Hackaday? Get this Golden Record and show an image on an oscilloscope. I’d love to see it, if only because it hasn’t been done before by someone independent from the original project.

How To Run A Pagekite Server To Expose Your Raspberry Pi

September 21, 2016 by 9 Comments

Last time I showed you how to expose a web service on a Raspberry Pi (or, actually, any kind of device) by using a reverse proxy from Pagekite. On your Pi, you just need a simple Python script. However, it also depends on the Pagekite server, which isn’t always convenient. There are limits to the free service, and you don’t control the entire thing. The good news is twofold: the same Python script you use to set up the client-side can also set up a server. The other good news is the entire thing is open source.

In practical terms, then, if you have a computer that is always on and has an IP address that can be found on the public internet, you can run your own Pagekite server (they call it a front end) and service your own backends.

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Classing Up A RetroPie Arcade With A Wine Barrel

September 20, 2016 by 20 Comments

Arcade cabinets are a lot of fun, and something most of us would probably like in our homes. Unfortunately, space and decor constraints often make them impractical. Or, at least, that’s what our significant others tell us. Surely there must be a workaround, right?

Right! In this case, the workaround [sid981] came up with was to build a RetroPie arcade into a fancy looking wine barrel. The electronics are pretty much what you’d expect for a RetroPie system, and the screen is set into the top of the barrel. Control is handled by a wireless controller that can be tucked away when it’s not in use, and a glass top simultaneously protects the screen and lets guests use the barrel as a bar table.

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Expose Your Raspberry Pi On Any Network

September 20, 2016 by 42 Comments

Everyone’s talking about the Internet of Things (IoT) these days. If you are a long-time Hackaday reader, I’d imagine you are like me and thinking: “so what?” We’ve been building network-connected embedded systems for years. Back in 2003, I wrote a book called Embedded Internet Design — save your money, it is way out of date now and the hardware it describes is all obsolete. But my point is, the Internet of Things isn’t a child of this decade. Only the name is.

The big news — if you can call it that — is that the network is virtually everywhere. That means you can connect things you never would have before. It also means you get a lot of data you have to find a reason to use. Back in 2003, it wasn’t always easy to get a board on the Internet. The TINI boards I used (later named MxTNI) had an Ethernet port. But your toaster or washing machine probably didn’t have a cable next to it in those days.

Today boards like the Raspberry Pi, the Beagle Bone, and their many imitators make it easy to get a small functioning computer on the network — wired or wireless. And wireless is everywhere. If it isn’t, you can do 3G or 4G. If you are out in the sticks, you can consider satellite. All of these options are cheaper than ever before.

The Problem

There’s still one problem. Sure, the network is everywhere. But that network is decidedly slanted at letting you get to the outside world. Want to read CNN or watch Netflix? Sure. But turning your computer into a server is a little different. Most low-cost network options are asymmetrical. They download faster than they upload. You can’t do much about that except throw more money at your network provider. But also, most inexpensive options expose one IP address to the world and then do Network Address Translation (NAT) to distribute service to local devices like PCs, phones, and tablets. What’s worse is, you share that public address with others, so your IP address is subject to change on a whim.

What do you do if you want to put a Raspberry Pi, for example, on a network and expose it? If you control the whole network, it isn’t that hard. You usually use some kind of dynamic DNS service that lets the Pi (or any computer) tell a well-known server its current IP address (see figure below).

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The Cicada: A Parasite Art Piece With Commitment Issues

September 19, 2016 by 18 Comments

How often do you think deeply about the products around you? How about those you owned five years ago? Ten? The Cicada — brainchild of [Daniel Kerris] — is an art piece that aims to have the observer reflect on consumer culture, buyer’s remorse, and wanting what we cannot have.

The Cicada consists of an ultrasonic sensor feeding data to a Raspberry pi which — calculating the distance of an approaching human — either speeds up or slows down a servo motor connected to a General Electric Walkman’s cassette speed potentiometer. Upon detecting someone approaching, The Cicada begins to loop the chorus of Celine Dion’s “I Will Always Love You”. As you move closer, the tape speed slows, and there is a transition from love at first sight to nightmarish drawl as the music slows.

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Hackaday Prize Entry: Text To Speech The Hard Way

September 18, 2016 by 10 Comments

Studies have shown reading to children leads to improved academic performance later in life, a trait that will make them more competitive in the workforce, and ultimately happier human beings. It follows, then, that having a robot read to children will also lead to happier and more productive adults, while normalizing the cyborg uprising takeover of the AI apocalypse of 2037.

It’s a good thing the above paragraph is a complete non-sequitur and has nothing to do with this Hackaday Prize entry. The TextEye, [Markus]’ entry for the Assistive Technology portion of the Hackaday Prize, is a handheld device that translates the written word into speech, useful for anyone who either can’t see well or can’t read gooder. Yes, it will also read to children, but so did Teddy Ruxpin.

If you’re keeping track, this isn’t the first time [Markus] has entered this project in a Hackaday Prize contest. The first time was six months ago in the Hackaday / Adafruit Raspberry Pi Zero contest. [Markus] was inspired by a group of blind computer science students using specialized hardware that allowed them to study the same thing as everyone else.

Since the first few project logs, a lot has changed in this project. You can buy a Pi Zero easily, and the updated Pi Zero 1.3 now comes with a camera connector. [Markus] is swapping out his Pi Model A and USB webcam for the Pi Zero and Pi camera. The software remains the same — GraphicsMagick, Tesseract OCR, Festival and Wiring Pi handle reading text and turning those words into speech — with a slight refactoring of the code. It’s a great use for the Pi Zero, and an excellent example of an Assistive Technology, and we’re happy to see it again in the Hackaday Prize.

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