ADC For Raspi Without Using An ADC

Schematic of ACD for a raspi

With all the amazing and wonderful things a Raspberry Pi can do, it is sorely lacking a dedicated ADC chip. Sure, you can wire up an ADC via SPI or even I2C with a little work, but still. It would be nice to have access to an Analog to Digital converter without having to go through the trouble. Fortunately, [Hussam] has figured out a way to do just this.

Using a comparator, two resistors, a single capacitor and a few lines of code, [Hussam] managed to get an active ADC working on his Raspberry Pi. He’s using the PWM1 and a passive RC filter to make a DAC. He then uses the comparator along with a ‘ successive approximation algorithm’ to complete the ADC.

[Hussam] mentions that the hack is not new, and this technique has been used before for microcrotrollers that lack a built-in ADC. But we are still impressed with his attention to detail in describing how to do this on a Raspi. Be sure to check out the link for full details, code, and an awesome description on how his algorithm works.

Introducing The Raspberry Pi B+


Click to embiggen

It looks like Element 14 screwed up a single shipment, because some lucky soul just received an unreleased model of Raspberry Pi. If you can believe the silkscreen, it’s called the Raspberry Pi Model B+, and while we have no idea what the chipset is, the layout and peripherals look pretty cool.

From the looks of it, this new board features four USB ports, a new, 40-pin GPIO header, and more screw holes that will allow you to secure this to anything. The analog video out is gone, and the SD card connector – a weak point of the original design – might be replaced with a microSD connector. Oh, every Raspi case that has ever been made? They won’t work.

Without booting this Raspi B+ there’s no way of knowing what the chipset is on this new board. The smart money is on the entire SOC being the same: basically, what you’re looking at is the same as a Raspberry Pi Model B, only with a few more ports.

There is no clue when these improved Raspis will be available, but the word “soon™” will probably appear on the Raspberry Pi blog shortly.

Thanks [John] for the tip.

EDIT: [feuerrot] is smarter than me and mirrored all the images in an imgur album.


Pi Musicbox 0.5 Released

Pi MusicBox Logo


Have an extra Raspberry Pi kicking around? Pi MusicBox provides a way to quickly turn it into a standalone streaming device that can fetch music from tons of sources. The latest release of Pi MusicBox adds a bunch of new features.

We took a look at this software over a year ago, and noted that it made streaming Spotify easy, and had support for controlling tracks using Music Player Daemon (MPD). The newest release supports AirPlay, DNLA, Google Music, SoundCloud, and several other music sources.

Since the analog audio output on the Pi isn’t great, Pi MusicBox includes support for a variety of USB sound cards. It’s also possible to use the HDMI port for digital audio output, which can be connected into your home theatre system.

If you want to build a standalone music device, this looks like a great place to start. The user community has built a variety of projects that run this software, which are featured on the Pi MusicBox homepage.

Pi-Powered Anti-Cat Trap Soaks Felines and Other Animals

Sprinkler Surprise

[Joshua] has a problem with cats. They like pooping in his garden. He decided to take action with this awesome automated and humane cat trap.

Now just to clarify, he did attempt a few other alternatives before going all out in cat defense – the easiest solution would be to get a cat of his own, but alas, he’s not a cat person.

The system uses a Raspberry Pi in a waterproofed housing with a PiCam. He’s written some rudimentary code to make use of the PiCam Python Library which also allows him to record pre-cat-trapping footage, much for our enjoyment. When motion is sensed, the Pi trips a 24VAC solenoid water valve, which turns on the sprinkler and quickly soaks the intruder.

Stick around after the break for quite a few videos catching the furry little buggers in the act!

[Read more...]

The Raspi GameBoy For The Rest Of Us

We’ve seen quite a few casemods that stuff a Raspberry Pi into a Game Boy with all the required to turn it into a very cool portable Pi and retro gaming device. Most of these builds use a modified 20-year-old Game Boy for the enclosure, and if you have an attachment to your old green screened friend, you might not want to cut it up for a Pi project. [Noe] over at Adafruit has a solution – a 3D printed Game Boy enclosure that turns a Pi and TFT screen into a barely pocketable Raspberry Pi, with all the buttons and batteries required for taking an installation of RetroPi on the road.

The PiGRRL, as this build is called, uses the Adafruit touchscreen TFT kit for the Pi, effectively turning the Pi into a very tiny tablet. This allows for normal desktop interaction with the Pi, and it’s also small enough to fit in the smallest of enclosures.

The 3D printed enclosure is the star of the show here, allowing complete access to most of the Pi’s ports, while allowing enough space in the rest of the enclosure for a largish battery, charging circuit, and buttons taken from an SNES controller.

The end result is a very usable portable Pi that just happens to be in the perfect form factor for loading up a few ROMs and playing some classic video games. Video below.

[Read more...]

Move Over Humans and Things, Flowers Now On The ‘Net

Tweeting Poppy Plants

The ‘Internet of Flowers’ is upon us thanks to an artist named [Adrian]. He has designed a project that not only monitors the growth of Poppy Flowers but also monitors the soil, air and surrounding activity.

The entire project is based on a Raspberry Pi mounted in a purpose-built enclosure made from laser cut birch plywood. The enclosure is mounted in a window of an adjacent building that has a view of the flower bed. An internally mounted camera was carefully aligned so its field of view was mostly of the plants and would limit taking photos of unknowing passersby. The camera takes a snap shot every 5 minutes, see the time lapse video below.

Tweeting Poppy PlantsA box containing sensors is installed in the flower bed. The intent of this project was not to have the Raspberry Pi spit out hard factual data regarding soil moistness, temperature and ambient noise, but to instead take that data from the sensors and send out a story-like narrative that makes the communication feel more personal. To receive these comments from the poppies, you can follow them on Twitter: @tweetingpoppy.

[Read more...]

Retro Gaming Console, Now With Internet Radio

RaspPi Retro Gaming Console with Internet Radio

Do you ever miss your gaming system of yesteryear? [yv3] did so he built a retro gaming console. Even though [yv3] likes his old school games, he didn’t want to be stuck listening to old school 8-track tapes while playing those games. The solution for him was to build a retro gaming console with integrated internet radio.

The gaming portion of the build relies on RetroPie. The RetroPie disk image contains all of the software and emulators needed to turn a Raspberry Pi into a dedicated retro gaming system. The RetroPie project supports a lot of gaming systems, [yv3] chose to include Atari, Sega Master System and Genesis, NES, SNES, and Turbografx-16.

Raspberry Pi Internet Radio manages the radio portion of this project and is set up to start playing automatically when the unit is powered on. There are 5 buttons to change the station, volume and settings. The radio stations are managed by a text file residing on the SD card. Audio from the radio can be directed to either the HDMI or the analog out of the RaspPi.

[Read more...]