Raspberry Pi

1836 Articles

The Live Still Life

June 14, 2015 by 15 Comments

Here’s a project that brings together artist [Justus Bruns] and engineers [Rishi Bhatnagar] and [Michel Jansen] to collaborate on an interactive work of Art. The Live Still Life is a classic still life, streamed live from India to anywhere in the world. It is the first step towards the creation of an art factory, where hundreds of these works will be made, preserved and streamed.

The Live Still Life is a physical composition of fresh fruit and vegetables displayed on a table with flatware, cutlery and other still objects. This is located in a wooden box in Bangalore. Every minute a photo is taken and the image is streamed, live, accessible instantly from anywhere in the world. Les Oiseaux de Merde’s Indian curator is on call to replace the fruit the minute it starts to rot so as to maintain the integrity of the image. In this way, while the image remains the same, the fight against decay is always present. The live stream can be viewed at this link.

The hardware is quite minimal. An internet connected Raspberry Pi model B,  Raspberry Pi camera module, a desk lamp for illumination and a wooden enclosure to house it all including the artwork. Getting the camera to work was just a few lines of code in Python. Live streaming the camera pictures took quite a bit more work than they expected. The server was written using a module called Exprestify written on top of Express JS to facilitate easier RESTful functions. For something that looks straightforward, the team had to overcome several coding challenges, so if you’d like to dig in to the code, some of it is hosted on Github or you can ask [Rishi] since he still needs to clean it up quite a bit.

Wifibroadcast Makes WiFi FPV Video More Like Analog

June 13, 2015 by 23 Comments

Normal WiFi is not what you want to send video from your quadcopter back to the first-person-view (FPV) goggles strapped on your head, because it’s designed for 100% correct, two-way transmission of data between just two radios. Transmission of analog video signals, on the other hand, is lossy, one-way, and one-to-many, which is why the longer-range FPV flights all tend to use old-school analog video transmission.

When you’re near the edge of your radios’ range, you care much more about getting any image in a timely fashion than about getting the entire video sequence correctly after a delay. While WiFi is retransmitting packets and your video is buffering, your quadcopter is crashing, and you don’t need every video frame to be perfect in order to get an idea of how to save it. And finally, it’s just a lot easier to optimize both ends of a one-way transmission system than it is to build antennas that must receive and transmit symmetrically.

And that’s why [Befinitiv] wrote wifibroadcast: to give his WiFi FPV video system some of the virtues of analog broadcast.

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SamplerBox Uses Raspberry Pi 2 To Make Music

June 12, 2015 by 16 Comments

[JosephErnest] wanted a cost-effective alternative to the commercially available MIDI samplers and expanders on the market. He also wanted to avoid being tethered to a computer all the time. His solution is the SamplerBox, a standalone drop-and-play sampler that costs less than 100 euros to make. Simply insert an SD card with your sample set in WAV format, boot it up, and play it through your keyboard or MIDI controller to your heart’s content!

[JosephErnest] used a Raspberry Pi 2 in the SamplerBox because it provided higher performance. He wasn’t thrilled with the sound quality of its built-in soundcard, so he installed a USB DAC PCM2704 (an older model, but any USB DAC will do) to output the audio. He also installed a USB card reader to make switching SD cards containing sampler sets easier while keeping the Pi 2’s own microUSB card exclusively for the OS and software. Both a DIN MIDI connector and USB are included as MIDI inputs in the design. If you only plan to use a USB, the MIDI connector can be omitted from the build. The software is written in Python and cython which allows the Pi 2 to have over 128-voice polyphony. Users can also create their own sample sets to use with the SamplerBox. Preset changes can be made on the fly. All we need to rock out are some music lessons!

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Portabilizing The Kinect

June 11, 2015 by 37 Comments

Way back when the Kinect was first released, there was a realization that this device would be the future of everything 3D. It was augmented reality, it was a new computer interface, it was a cool sensor for robotics applications, and it was a 3D scanner. When the first open source driver for the Kinect was released, we were assured that this is how we would get 3D data from real objects into a computer.

Since then, not much happened. We’re not using the Kinect for a UI, potato gamers were horrified they would be forced to buy the Kinect 2 with the new Xbox, and you’d be hard pressed to find a Kinect in a robot. 3D scanning is the only field where the Kinect hasn’t been over hyped, and even there it’s still a relatively complex setup.

This doesn’t mean a Kinect 3D scanner isn’t an object of desire for some people, or that it’s impossible to build a portabilzed version. [Mario]’s girlfriend works as an archaeologist, and having a tool to scan objects and places in 3D would be great for her. Because of this, [Mario] is building a handheld 3D scanner with a Raspberry Pi 2 and a Kinect.

This isn’t the first time we’ve seen a portablized Kinect. Way back in 2012, the Kinect was made handheld with the help of a Gumstix board. Since then, a million tiny ARM single board computers have popped up, and battery packs are readily available. It was only a matter of time until someone stepped up to the plate, and [Mario] was the guy.

The problem facing [Mario] isn’t hardware. Anyone can pick up a Kinect at Gamestop, the Raspberry Pi 2 should be more than capable of reading the depth sensor on the Kinect, and these parts can be tied together with 3D printed parts. The real problem is the software, and so far [Mario] has Libfreenect compiling without a problem on the Pi2. The project still requires a lot of additional libraries including some OpenCV stuff, but so far [Mario] has everything working.

You can check out his video of the proof of concept below.

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PiClock

PiClock – Time And Weather Information Overload

June 10, 2015 by 48 Comments

[Kevin] wanted a display where he could take a quick glance and get all the current environmental information he uses throughout the day. That information includes, of course, the time and date as well as weather information. We’re not just talking the current weather information but the forecast for the upcoming week as well as a map showing current weather patterns. To do this, [Kevin] came up with a unique system he’s calling the PiClock.

[Kevin] did some serious programming to get this clock project off of the ground. The weather data comes via the Weather Underground API and the map data from the Google Maps API. The main program is written in Python and will run on any OS running Python 2.7+ and PyQt4. If you’re interested in doing something similar, check out the source at github.

From the project’s name, it is no surprise that a Raspberry Pi is the brains here. A USB WiFi adapter allows access to the internet but an Ethernet connection would do just fine. Having the RaspPi hanging out with wires everywhere would be a little lazy, so [Kevin] opened up his 19″ LCD monitor and mounted the RaspPi inside the case. He tapped 5vdc off of the monitors power supply and used that to power the RaspPi, no external wall wart necessary! And if the PiClock’s background isn’t cool enough, some RGB LED strips were mounted to the back of the monitor to give an Ambilight effect.

Monitoring Power With A 555

June 7, 2015 by 12 Comments

[Diederich] is running a Raspberry Pi loaded up with Pimatic, a great home automation server that does just about anything you can throw at it. One thing it doesn’t do is monitor electricity and gas directly from the meter – you’re going to need hardware for that. [Diederich] stepped up to the plate and built that hardware using just a 555 timer. The total cost of adding this to his Pimatic setup was less than a dollar.

The 555 can be used as a timer, a trigger, and a bunch of them can be cobbled together into a CPU. [Diederich] isn’t using some fancy logic here; he’s just using the 555 as a Schmitt trigger with a phototransistor and his electricity meter. The output of the 555 is connected to the GPIO of the Raspberry Pi, and a Python script ties into Pimatic.

It’s a neat solution that only costs a dollar, and using the 555 has a few advantages: the 555 makes it possible to use long and thin wires back to the Pi, which means [Diederich]’s Pi doesn’t have to be located right next to his meter.

Smile For The Raspberry Pi Powered Photo Booth

June 5, 2015 by 5 Comments

[Roo] was tasked with finding a better way to take corporate employee photos. The standard method was for a human resources employee to use a point and shoot camera to take a photo of the new recruits. The problem with this method is many people feel awkward trying to force a smile in front of other people. Plus, if the photo turns out poorly many people won’t ask to have it retaken so as not to feel vain or inconvenience the photographer. [Roo’s] Raspberry Pi powered photo booth solves this problem in a novel way.

The new system has the employee use their own mobile phone to connect to a website running on the Pi. When the employee tells the Pi to snap a photo, the system uses the Raspberry Pi camera module to capture an image. [Roo] actually 3D printed a custom adapter allowing him to replace the standard camera lens if desired. The photo can be displayed on an LCD screen so the user can re-take the photo if they wish.

The system is built into a custom case made from both 3D printed and laser cut parts. The front plate is a frosted white color. [Roo] placed bright white lights behind the front panel in order to act as a flash. The frosted plastic diffuses the light just enough to provide a soft white light for each photo taken. Once the photo is selected, it can then be uploaded to the company database for use with emails, badges, or whatever else.

[Roo] also mentions that the system can easily be changed to send photos via Twitter or other web applications. With that in mind, this system could be a great addition to any hackerspace or event. The code for an older version of the project can be found on the project’s github page.

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