Raspberry Pi

1887 Articles

Slack, Backwards Compatible With 1982

November 29, 2016 by 13 Comments

Slack is great, but there are a few small problems with the current implementations. There isn’t a client for Palm, there isn’t a client for the Newton, and there isn’t a client for the Commodore 64. The last of these severe oversights was recently fixed by [Jeff Harris]. He built a native Slack client in 6502 assembly for the Commodore 64.

When dealing with network applications and the C64, the first question that comes to mind is how to talk to the outside world. There are C64 NICs, and ESP dongles, but for this build [Jeff] turned to the C64 Userport. This card edge combination of a serial and parallel port allows the C64 to talk to anything with RS-232, and with a simple adapter, [Jeff] got his old computer talking to a Raspberry Pi connected to the Internet.

The C64 Slack client itself is written in 6502 assembly, and features everything you would expect. The Pi is required to talk to the Slack API, though, and uses a NodeJS app to translate the bits from the C64 to something the API can understand.

Does it work? Of course it does. Slack is just text, after all, and there doesn’t seem to be any PETSCII weirdness here. You can check out a video of the build in action below.

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Controlling Your Instruments From A Computer: Doing Something Useful

November 29, 2016 by 6 Comments

Do you know how to harvest data from your bench tools, like plotting bandwidth from your oscilloscope with a computer? It’s actually pretty easy. Many bench tools make this easy using a standard protocol with USB to make the connection.

In the previous installment of this article we talked about the National Instruments VISA (Virtual Instrument Software Archetecture) standard for communicating with your instruments from a computer, and introduced its Python wrapper with a simple demonstration using a Raspberry Pi. We’ll now build on that modest start by describing a more useful application for a Raspberry Pi and a digital oscilloscope; we’ll plot the bandwidth of an RF filter. We’ll assume that you’ve read the previous installment and have both Python and the required libraries on your machine. In our case the computer is a Raspberry Pi and the instrument is a Rigol DS1054z, but similar techniques could be employed with other computers and instruments.

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Controlling A Game Room With Amazon Echo

November 27, 2016 by 2 Comments

If there are two things we love here at Hackaday, it’s games and automating mundane tasks by adding a lot of electronics and voice control. A game room is, therefore, the perfect sandbox for projects that get us excited in all of the right ways. Liberty Games, a UK-based games room company, already had a really impressive game room (as you might expect). They’ve just posted an awesome build log showcasing how they went about automating mundane game room tasks by adding a lot of electronics and voice control.

There were four tasks that Liberty Games wanted to be able to complete with voice control: releasing billiards balls on their pool table, adding credits to an arcade machine, releasing pinballs on a pinball machine, and control of a CD jukebox. For all of these tasks, they used an Amazon Echo, which already has built-in support for adding new “skills” (Amazon’s term for user-created Alexa commands). These skills allow the Echo to communicate with other devices using JavaScript Object Notation (JSON).

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DIYing A Raspberry Pi Power Bank

November 26, 2016 by 25 Comments

Over the last decade or so, battery technology has improved massively. While those lithium cells have enabled thin, powerful smartphones and quadcopters, [patrick] thought it would be a good idea to do something a little simpler. He built a USB power bank with an 18650 cell. While it would be easier to simply buy a USB power bank, that’s not really the point, is it?

This project is the follow-up to one of [patrick]’s earlier projects, a battery backup for the Raspberry Pi. This earlier project used an 14500 cell and an MSP430 microcontroller to shut the Pi down gracefully when the battery was nearing depletion.

While the original project worked well with the low power consumption Pi Model A and Pi Zero, it struggled with UPS duties on the higher power Pi 3. [patrick] upgraded the cell and changed the electronics to provide enough current to keep a high-power Pi on even at 100% CPU load.

The end result is a USB power bank that’s able to keep a Raspberry Pi alive for a few hours and stays relatively cool.

Low-cost Video Streaming With A Webcam And Raspberry Pi

November 25, 2016 by 32 Comments

Some people will tell you that YouTube has become a vast wasteland of entertainment like the boob tube before it. Live streaming doesn’t help the situation much, and this entry level webcam live-stream server isn’t poised to advance the art.

We jest, but only a little. [Mike Haldas] runs a video surveillance company that sells all manner of web-enabled cameras and wondered what it would take to get a low-end camera set up for live streaming. The first step was converting the Zavio webcam stream from RTSP (real-time streaming protocol) to the standard that YouTube uses, RTMP (real-time messaging protocol). Luckily, FFmpeg handles that conversion, so he compiled it for his MacBook Pro and set up a proof of concept. It worked, but he needed a compact solution that would free up his laptop. Raspberry Pi to the rescue – after loading a bunch of libraries and a four-hour build and install of FFmpeg, the webcam was streaming 1080p video of [Mike]’s sales office. He was worried that the Pi wouldn’t have the power needed for the job, and that it would be unstable. But as of this writing, the stream below has been active for six days, and it’s riveting stuff.

Raspberry Pis are a staple in the audio streaming world, like this pro-grade FM broadcast streaming rack or this minuscule internet radio streamer. And of course there’s this quick and dirty, warm and fuzzy streaming baby monitor.

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Raspberry Pi Radio Makes The Sweet Music Of Bacteria

November 25, 2016 by 5 Comments

We’ve noticed a lot of musical groups are named after insects. Probably has something to do with the Beatles. (If you study that for a while you’ll spot the homophonic pun, and yes we know that the Crickets inspired the name.) There’s also Iron Butterfly, Adam Ant, and quite a few more. A recent art project by a Mexican team — Micro-ritmos — might inspire some musical groups to be named after bacteria.

The group used geobacter — a kind of bacteria found in soil — a Raspberry Pi, an Arduino, and a camera to build an interesting device. As it looks at the bacteria and uses SuperCollider to create music and lighting from the patterns. You can see a video of Micro-ritmos, below.

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Faulty Parking Meter Tracking System? RFID To The Rescue!

November 21, 2016 by 2 Comments

How often do you see problems that need fixing? How often do you design your own solutions to them — even if they won’t be implemented at scale? Seeing that many of the municipal parking lots in his native Sri Lanka use a paper ticketing system which is prone to failure, [Shazin Sadakath] whipped up his own solution: an efficient RFID tag logging system.

Digging out an HZ-1050 RFID reader — as well an RFID card and two tags — [Sadakath] set to work connecting it to his Raspberry Pi and cooking up a batch of code and a dashboard to work with. A Python script — using a PiGPIO library — reads the Wiegand Format RFID number, storing it in an SQLite3 database. A Bootstrap, Javascript, and JQuery trifecta make up the dashboard that pulls the RFID info from said server and organizes it into a functional format.

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