Raspberry Pi

1932 Articles

Meet ‘Raspberri’, Your Personal Voice Controlled Assistant

February 7, 2014 by 15 Comments

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We’ve all seen the old movie scene where the executive calls his assistant on the intercom for some task or other. [Jan] may not be an executive, and he may not have an assistant. He does have Raspberri, his voice controlled personal digital assistant. Raspberri started life as a vintage Televox intercom box. [Jan] found it at a second-hand store, and snapped it up in hopes of using it in a future project. That project eventually happened when [Jan] got a Raspberry Pi and learned how to use it. He decided to build the Televox and Pi together, creating his own electronic assistant.

[Jan] started by adding a cheap USB sound card and WiFi module to his Pi. He also added a small 3 Watt audio amp board. The Televox used a single speaker as both audio input and output. [Jan] didn’t want to make any modifications to the case, so he kept this arrangement. Using a single speaker would mean dead shorting the audio amplifier and the sound card’s microphone input. To avoid this, [Jan] added a DPDT relay controlled by the original push-to-talk button on the Televox. The relay switches between the microphone input and the audio output on the USB sound card. Everything fit nicely inside the Televox case.

With the hardware complete [Jan] turned his attention to software. He went with PiAUISuite for voice input. Voice output is handled by a simple shell script which uses google voice to convert text to speech. For intermediate processing, such as scraping a weather website for data, [Jan] created custom python scripts. The end result is pretty darn good. There is a bit of lag between saying the command and receiving an answer. This may be due to transferring the audio files over WiFi. However,  [Jan] can always get away with saying his assistant was out getting him more coffee!

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Thumbs-Down Songs On Pandora With Your Mind

February 7, 2014 by 12 Comments

[Steven] likes music. Like many of us, he uses Pandora to enjoy the familiar and to discover new music. Now, Pandora means well, but she gets it wrong sometimes. [Steven] has had a Mindwave Mobile EEG headset lying around for a while and decided to put it to good use. With the aid of a Raspberry Pi and a bluetooth module, he built a brainwave-controlled Pandora track advancing system.

The idea is to recognize that you dislike a song based on your brainwaves. The Mindwave gives data for many different brainwaves as well as approximating your attention and meditation levels. Since [Steven] isn’t well-versed in brainwavery, he used Bayesian estimation to generate two multivariate Gaussian models. One represents good music, and the other represents bad music. The resulting algorithm is about 70% accurate, so [Steven]’s Python script waits for four “bad music” estimations in a row before advancing the track.

[Steven] streams Pandora through pianobar and has a modified version of the control-pianobar script in his GitHub repo.  His script will also alert you if the headset isn’t getting good skin contact, a variable that the Mindwave reports on a scale of 0 to 200.

Stick around for a demo of [Steven] controlling Pandora with his mind. If you don’t have an EEG headset, you can still control Pandora with a Pi, pianobar, and some nice clicky buttons.

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Pi-Powered Radio Over IP

February 6, 2014 by 12 Comments

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[KP4TR] connected a Raspberry Pi to a small, cheap handheld radio, allowing anyone within a few miles of his house to connect to amateur radio operators all around the world.

For the hardware, [KP4TR] is using a Raspi, a Baofeng BF-888s 400MHz – 470MHz walkie-talkie radio, a USB sound card, and a pair of transformers for the 5V and 3.7V lines. All this is tucked away in a remakably vintage-looking plate and standoff enclosure, complete with acorn nuts and an RGB LED connected to the Raspi’s GPIO to indicate whether the radio is transmitting or receiving.

The software used is SVXLink, a Linux port of the Echolink software. This app allows hams the world over to connect to very distant radios over the Internet.

You can check out the video demos of the system below.

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RasPi “Inception” CD-ROM Case Mod

February 1, 2014 by 9 Comments

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At first glance, [John’s] CD-ROM RasPi case may not seem all that unique, but we like both the implementation as well as the end-result functionality it provides. His goal was to use the Pi as a torrent downloader, and to store the downloaded files on a shared network drive. The Pi drive would slide into a bay in the server’s case—hence the Inception reference: a computer in a computer—allowing downloads while putting another step between the server and the outside world keeping, as well as guaranteeing that the network share would be available, because the server and the Pi would use the same power source.

[John] gutted the CD-ROM’s internals to leave only the PCB, which he stripped of most everything save for the power connector in the back. He then used the base of his old RasPi case as a standoff, mounting it to the top of the CD-ROM’s PCB. He soldered the power lines to the ROM’s power connector and temporarily hooked up a 5V adapter until he gets the server running. The final step was to carve out the back of the case for access to the Ethernet and USB ports, which [John] accomplished with a dremel, a hacksaw and a file. The front of the case still looks like a stock CD-ROM drive, and [John] has plans for future mods: re-purposing the LED to show network activity and modifying the buttons to serve as a reset, pause, or start for torrent downloads.

FFT On The Raspi’s GPU

January 31, 2014 by 17 Comments

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The Raspberry Pi has been around for two years now, and still there’s little the hardware hacker can actually do with the integrated GPU. That just changed, as the Raspberry Pi foundation just announced a library for Fourier transforms using the GPU.

For those of you who haven’t yet taken your DSP course, fourier transforms take a function (or audio signal, radio signal, or what have you) and output the fundamental frequency. It’s damn useful for everything from software defined radios to guitar pedals, and the new GPU_FFT library is about ten times faster at this task than the Raspi’s CPU.

You can get a copy of  the GPU_FFT library by running rpi-update on your pi. If you happen to build anything interesting – something with a software defined radio or even a guitar pedal – you’re more than welcome to send it in to the Hackaday tips line. We’d love to see what you’re up to.

Pan Flute Hero

January 30, 2014 by 21 Comments

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The latest creation in the never-ending collection of “____ Hero” instruments is this Raspi-infused pan flute, built by [Sven Andersson] and his team at the 2013 WOW Hackathon. The flute itself consists of varying lengths of bamboo from a local flower shop, cut short enough to be hand-held while still hiding the Pi from the front side. In the spirit of other ‘Hero’ instruments, the pan flute has no real musical functionality. Each pipe houses what appears to be an electret microphone breakout board, which they kept in place by sealing off the end of the pipe with glue.

The sensors connect to the GPIO connector on the Raspi, which communicates to a local TCP/IP server the team ran as a controller hub. The game is also their original creation, written entirely in LUA. They turned to Spotify to find suitable material for the player to experience, creating playlists with actual pan flute songs and using the libspotify SDK to access the music. You can see the end result of the project in a short demo video below.

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S.A.M. The Safety Attention Monitor

January 30, 2014 by 19 Comments

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Last term’s project at Chico State University hopes to reduce driver distraction by alerting you when it notices you aren’t paying attention (to the road!).

The team designed SAM using OpenCV to track your face in order to recognize when you aren’t watching the road. It alerts you through a variety of audible beeps and LED lights, and is programmed to only alert you after set time values — i.e. it’s not going to go off when you’re checking your blind spot, unless you’ve been checking it for over a certain length of time. It also has a silence button you can press for situations like looking around while you are parked.

The proof of concept device was built using a Raspberry Pi, the PiCam, and a breadboard to accommodate some manual controls, the buzzer, and LEDs. It also continuously records video of you on a 30 second loop, and in the event of an accident, it saves all the video — perhaps proving it was your fault. Can you imagine if all cars had this installed? On the plus side you wouldn’t have to argue with insurance companies — but if it really was your fault, well then you’re straight out of luck.