Raspberry Pi Halt And Catch… Well, Halt

August 25, 2015 by Al Williams 38 Comments

As far back as we can remember, there have always been hacks, exploits, and just curiosity about undocumented CPU instructions. The Z80 had them. Even the HP41C calculator had some undocumented codes. The HCF (Halt and Catch Fire) instruction was apocryphal, but we always heard the old video controller chips could be coaxed into blowing up certain monitors. You don’t hear too much about things like that lately, perhaps because fewer people are working in assembly language.

[Sergi Àlvarez i Capilla] not only works in assembly language, he was writing an ARM assembler when he noticed something funny. Instructions are built in a regular pattern and some of the patterns were missing. What to do? [Sergi] lost no time trying them out.

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Follow Me: Making Servos Track Hand Motion With Leap

August 22, 2015 by Al Williams 5 Comments

The Leap controller is one of those gadgets that is probably better for its cool factor rather than its practicality. The ~~time of flight~~ optical sensor reads gestures, but it is hardly a substitute for a mouse in many cases. It seems like the best uses for it we’ve seen are dedicated systems that need to know where your hands are. [Justin Platz] and [Kurt Clothier], for example, have an interesting demo that uses a Leap to control a Raspberry Pi. The Pi commands servo motors that move LED blocks to track your hand motion. Their code is available on GitHub.

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Hackaday Prize Entry: Twitter Goes To The Dogs With Raspberry Pi Hack

August 21, 2015 by Richard Baguley 7 Comments

Dogs are remarkable creatures. Anybody who has lived with one will know that they are very vocal beasts, with barks that range from noting the presence of a squirrel in the yard to the warning whine that says “I am about to pee on your shoes if you don’t take me outside.” [Henry Conklin] decided to computerize the analysis of these noises, putting his dog [Oliver Twitch] on Twitter so he could hear what he was saying while he was at work. [Henry] that is: [Oliver] stays at home.

He did this using a Raspberry Pi, which is set to record sound above a certain volume. With the system sitting by [Oliver’s] favorite window, this records his barks. The recordings are then analyzed using PyAudioAnalysis, a library that analyzes sounds, compares them to reference ones and classifies them. The Raspberry Pi then posts the results onto twitter using Python-twitter.

The setup used by [Oliver] to capture the barks: a USB microphone, Raspberry Pi and WiFi USB dongle.

Or rather, it will when [Henry] fixes a few bugs: right now it just posts a random string that is based on the length of the bark, not the type. [Henry] says he is working on the dog translation at the moment. It’s still a neat project that shows you how simple it is to use a few small bits of code to gather info from your environment and share these over the Internet. [Henry] also says that the next step is creating a weekly podcast for [Oliver]. I, for one, will be subscribing to hear his thoughts on how annoying the postman is, and how vexing it is to see a squirrel and not be able to chase them.

The 2015 Hackaday Prize is sponsored by:

Easy To Read Bicycle Computer

August 21, 2015 by Al Williams 12 Comments

[David Schneider] had trouble seeing his bike computer in the sunlight and wanted a navigation solution that would be both readable and not require a smart phone. In good hacker fashion, [David] married a Raspberry Pi and a Kindle Touch (the kind with the E-ink display). The Kindle provides a large and easy-to-read display.

[David] was worried about violating the DCMA by modifying the Kindle. Turns out, he didn’t have to. He simply used the book reader’s Web browser and set the Pi up as a wireless access point. One clever wrinkle: Apparently, the Kindle tries to phone home to Amazon when it connects to a wireless network. If it can’t find Amazon, it assumes there’s no valid network and treats the network as invalid. To solve this issue, [David] causes the Pi to spoof the Kindle into thinking it gets a valid response from Amazon.

The other work around was to change how the Python application on the Pi updates the screen. [David] found that without that optimization, the constant redrawing on the E-ink display was annoying. The Pi-related hardware includes a GPS, some reed switches, and a WiFi dongle.

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New Version Of Raspberry Pi Thin Client

August 16, 2015 by Al Williams 18 Comments

It is funny how many times you use your full-blown PC as a terminal to another computer (which is quite often not as capable as the terminal computer). If all you need is a remote display and keyboard, a Raspberry PI would be enough. One of the newer Pi 2 boards would be even better.

You could roll your own set of remote access software, but you don’t have to. [Gibbio] has already created a thin client image called RPiTC and recently released version 1.4. The build supports diverse remote protocols including Microsoft Remote Desktop, Citrix, VMWare, and even X3270.

It supports WiFi and VPN. We were a little disappointed that it didn’t seem to have any serial communication programs (in case we wanted to build one into an old TeleType case). Of course, it is just a Linux system so you can install anything you want or need.

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Commodore C16 Resurrection With A Raspberry Pi

August 16, 2015 by Al Williams 27 Comments

[lactobacillusprime] had a non-working Commodore C16 and too many Raspberry Pi computers, so he decided to bring the C16 back to life by emulating it on the Pi. At the heart of the project is the Pi, along with a small board that converts the old style Commodore keyboards (and joysticks) to a USB port.

Once you have the keyboard as a USB port, the rest of the project is more or less mechanics and software. [lactobacillusprime] did a nice job of getting everything in the new case, along with all the I/O wires routed through the existing ports. For software, Emulation Station does the job of launching the Commodore emulation on the Pi.

Of course, there’s no reason to limit yourself to just the Commodore emulator. Emulation Station along with the right back end emulators will allow this machine to play games that no real Commodore C16 could.

Of course, we were happiest to see him boot up Commodore 64 BASIC. Perhaps we should complete all those half finished C64 BASIC projects we started back in the 1980’s. In general, we hate to see old computers gutted instead of repaired, but at least this one will continue running its software. If you are upset about seeing a machine gutted, you can always switch over to our previous coverage of putting Commodore guts in a new box.

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Covert Cricket Score Tracker Gets Around Office Rules

August 15, 2015 by Richard Baguley 15 Comments

[Rohit Gupta] was looking for a stealthy way to keep up with the scores for his favorite game: cricket. Unfortunately, his office blocked access to most sites where he could watch the game, so he came up with a covert way to track the score on a small LCD screen. Using a Raspberry Pi and the web scraping program BeautifulSoup, he wrote a program that grabbed the score once a minute, and displayed it on a screen salvaged from a Nokia 5510 cell phone, driven through the Adafruit 5510 Python display library. Web scraping is a technique where a program grabs a web page, scrapes all of the content off it and processes it so only the data that is needed remains.

[Rohit] doesn’t name the web site that he scraped the score from, but there are two good reasons for that. Firstly, this hack relies on his office not blocking it, and secondly, many web sites frown on web scraping like this, as doing it too often can overload their servers, and you obviously don’t see the ads that the site is running. So, it is a technique that should be used with some caution. That aside, this is a great example of a stealthy way to display information that you want to track, but without obnoxious (and obvious) alerts popping up on screen. And, given that cricket games can often go on for several days, that’s a good way to keep track of the game you love and keep your job.

Need a little primer on web scraping? Check out this guide.