raspberry pi

1647 Articles

New Part Day: Really, Really Wide Screens

March 7, 2015 by 70 Comments

Once again my inbox runneth over with press releases, Kickstarter announcements, unsolicited emails, and a bunch of product announcements. Most of these, of course, are never to be seen again. Once in a great while – statistically insignificant, really – there’s a product announcement that’s just interesting enough to take a closer look at. This time, it’s a really, really wide screen.

LCDs are curious beasts when it comes to display interfaces. Back in the bad old days of gigantic tube TVs, the aspect ratio of these displays was fairly limited. You could get a 4:3 display, and with the rare exception of o-scopes, vector displays, and other weird devices, that was it. Since then we’ve moved to LCDs, a promising technology if you want a display in the shape of a car dashboard, or as a thin strip to put on some rackmount modules. It took this long for a sliver of an LCD to appear.

This display produced by EarthLCD is a 10.4 inch display, about ten inches wide and one inch tall. The resolution is 1024 by 100. It is, by far, the skinniest LCD ever produced. The closest you’re going to get to a display with this kind of aspect ratio are old character LCDs, and even then you’re not going to address individual pixels.

If you’re struggling to figure out what this would be used for, this product makes it somewhat obvious. It’s a 1U rack with a beautiful 1024×100 display embedded in the front. You’ve never seen a server that cool.

Interestingly, the 1U display is driven by a single Raspberry Pi, and looking at the datasheet for the display (PDF) tells you pretty much everything. The display is driven by a regular old parallel interface, with six bits of color for R, G, and B. That means it can be driven with a Raspberry Pi without an adapter board, a BeagleBone, or even smaller ARM micros with the obvious reduction in color depth.

While the display isn’t a game changer or something that will knock your socks off, it is, interesting and something that could find its way into some interesting projects. If you have any idea what those projects would be, drop a note in the comments.

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Using Cheap Displays With The Raspberry Pi

March 5, 2015 by 63 Comments

The Raspberry Pi B+ has a native VGA connection. Sure, it’s hidden away in binary blobs and device trees, and you need to wire up the GPIO pins just right, but it’s possible to connect a VGA monitor to a Raspi B+ natively. For the brave, smart, or foolish, this means you can also drive raw DPI displays. [Robert] had a few of these dirt cheap displays sitting around and decided to give the entire thing a go. It worked, and he’s written down how to do it.

One of the chip architects for the Raspberry Pi, [Gert van Loo], was exceedingly clever when designing the Pi. There’s a parallel interface in the chip that, when combined with a few dozen resistors, can drive a VGA display in addition to the HDMI display. Screens with a Display Parallel Interface are actually pretty similar to what the VGA spec calls for. The problem is, hardly any of this is documented for the Raspberry Pi, and finding it means trawling through forums.

[Robert]’s example circuit uses a 5″ display from Adafruit, a 40-pin breakout, and a bunch of prototyping wires. Setup requires grabbing a cut down version of the device tree used for the Raspi VGA breakout board, setting the output format, rgb order, and aspect ratio of the display, and wiring everything up.

What’s interesting here is that [Robert] reproduced this project from scratch, and found that any display with a 40-pin DPI connector will work with the Raspi, provided you have a datasheet. That’s pretty cool; these displays can be cheap, and since we don’t yet have a proper DSI display for the Pi, this will have to do for now.

Video below of [Robert]’s inspiration for this build, [Ladyada].

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RetroPie Turned Game Gear

March 2, 2015 by 12 Comments

Running vintage console emulators on a Raspberry Pi seems to be the thing all the cool kids are doing. The coolest RetroPie builds take a vintage console – usually of the Nintendo genus – stuff a Raspi in there somehow, and Bob’s your uncle. [Phil Herlihy] over at Adafruit is throwing his hat into the ring with a similar build. For this one, though, he’s using Sega’s oft-maligned Game Gear. He might actually get more than a few hours out of the battery with this one, and the battery is rechargeable, too. You can’t beat that.

The build begins with tearing down an old Game Gear, chopping up the PCB to save the button contact, and starting to fit all the components in there. The display is completely replaced with a 3.5″ composite display, a bit larger than the 3.2″ display found in a stock Game Gear. That’s not a problem, there’s a surprising amount of space behind the bezel, and if you’re good enough with an xacto blade and a file, it will look stock.

The rest of the components include an amplifier board, battery charge regulator, a 2500mAh LiPo, and a Teensy to read the buttons. There are a few modifications required for the Pi, but the finished device presents a USB port to the outside world; keep a keyboard by your side, and this is a portable Pi in every respect.

An Upgrade To A Raspberry Pi Media Server

March 1, 2015 by 23 Comments

For the last few years, [Luke] has been running a music server with a Raspberry Pi. With the new Raspberry Pi 2 and its quad core processor, he thought it was time for an upgrade.

The build consists of a Raspi 2, a HiFiBerry Dac to address the complaints of terrible audio on the Pi, an aluminum enclosure, and some electronics for IO and a real software shutdown for the Pi. The Arduino also handles an IR remote and a rotary encoder on the front of the enclosure.

The software is the Logitech Media Server along with Squeezeslave. The front end is custom, though, with functions for shutdown and receiving IR remote codes. Everything is served up by Flask, with a 32GB microSD card stuffed into the Pi to store MP3s. All in all, a great build.

Raspberry Pi GSM Hat

February 28, 2015 by 12 Comments

The Spark Electron was released a few days ago, giving anyone with the Arduino IDE the ability to send data out over a GSM network. Of course, the Electron is just a GSM module tied to a microcontroller, and you can do the same thing with a Pi, some components, and a bit of wire.

The build is fairly basic – just an Adafruit Fona, a 2000 mah LiPo battery, a charge controller, and a fancy Hackaday Perma-Proto Hat, although a piece of perf board would work just as well in the case of the perma-proto board. Connections were as simple as power, ground, TX and RX. With a few libraries, you can access a Pi over the Internet anywhere that has cell service, or send data from the Pi without a WiFi connection.

If you decide to replicate this project, be aware you have an option of soldering the Fona module right side up or upside down. The former gives you pretty blinking LEDs, while the latter allows you to access the SIM. Tough choices, indeed.

Colorful Clock

A Colorful Clock For Toddlers

February 24, 2015 by 34 Comments

[Don] and his wife were looking for a way to teach their two-year old daughter how to tell time. She understood the difference between day and night, but she wasn’t old enough to really comprehend telling the actual time. [Don’s] solution was to simplify the problem by breaking time down into colored chunks representing different tasks or activities. For example, if the clock is yellow that might indicate that it’s time to play. If it’s purple, then it’s time to clean up your room.

[Don] started with a small, battery operated $10 clock from a local retailer. The simple clock had a digital readout with some spare room inside the case for extra components. It was also heavy enough to stay put on the counter or on a shelf. Don opened up the clock and got to work with his Dremel to free up some extra space. He then added a ShiftBrite module as a back light. The ShiftBrite is a high-brightness LED module that is controllable via Serial. This allows [Don] to set the back light to any color he wants.

[Don] already had a Raspberry Pi running his DIY baby monitor, so he opted to just hijack the same device to control the ShiftBrite. [Don] started out using a Hive13 GitHub repo to control the LED, but he found that it wasn’t suitable for this project. He ended up forking the project and altering it. His alterations allow him to set specific colors and then exit the program by typing a single command into the command line.

The color of the ShiftBrite is changed according to a schedule defined in the system’s crontab. [Don] installed Minicron, which provides a nice web interface to make it more pleasant to alter the cron job’s on the system. Now [Don] can easily adjust his daughter’s schedule via web page as needed.

 

Piana – Musical Synthesis For The Raspberry Pi

February 24, 2015 by 23 Comments

For the last 15 years or so, software synths have slowly yet surely replaced those beatboxes, drum machines, and true synthesizers. It’s a loss for old hardware aficionados, but at least everyone with a MacBook is now a musician, amiright?

The Raspberry Pi and Pi2 already have more processing power than a desktop from ’99, so it’s no surprise that all of those classic synths, from a Moog. Yamaha DX, Casio CZ, Linn drum machine, Fairlight, and a mellotron, can all be stuffed into a Pi thanks to the work of [Phil Atkin] and his Raspberry Pi synthesizer.

[Phil]’s efforts to bring audio synthesis to the Pi fall under three techniques: subtractive synthesis, phase distortion synthesis, and sample-based synthesis, something that’s found in everything from Akai MPCs, MacBooks, and that one episode of The Cosby Show. [Phil] is combining all of these techniques into a piece of software that’s capable of running seamlessly on the Pi, giving anyone with a $35 computer a tool that would have been worth several thousand dollars in 1985.

The project is pretty far along, but the recent release of the Raspberry Pi 2 has thrown [Phil] for a loop. On one hand, the Pi 2 is much more capable than the original Pi in terms of hardware, and this lends itself to more sounds and a better GUI. On the other hand, there are millions of original Pi 1s out there that still make for exceptional synthesizers. Either way, [Phil]’s work is a great example of how far you can push the Pi with audio work.

Thanks [Wybren] for the tip. Videos below.

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