Raspberry Pi UPS Using Supercapacitors

April 3, 2014 by James Hobson 21 Comments

What happens when you want to integrate a Raspberry Pi into some kind of project that gets turned on and off with mains voltage? Do you power the Pi separately, or make a UPS for it?

[Lutz Lisseck] decided he wanted to turn his ambient-lamp (Rundbuntplasma) on and off with only the main power switch in his Hackerpsace. He could build a traditional UPS using a battery pack (it’s only 5V after all!) but decided to take it a step further. He picked up a pair of 50F supercapacitors. This way his UPS would last longer than his Pi would! The caps store just enough power that when the main supply is cut, a GPIO notices, tells the Pi, and it begins a shutdown sequence lasting about 30 seconds.

While [Lutz] is using two 2.7V supercapacitors, he mentions it would be a lot cheaper to use a step-up converter instead of putting them in series — but he had the caps on hand so decided to use both.

If you need it to last a bit longer, you could make one with rechargeable batteries…

Raspberry Pi Quake III Bounty Claimed

March 31, 2014 by Brian Benchoff 29 Comments

quake3

For the Raspberry Pi’s second birthday, the Raspi foundation gave us all a very cool gift. Broadcom released the full documentation for the graphics on one of their cellphone chips and offered up a $10k prize to the first person to port that code over to the graphics processor on the Pi and run Quake III. The prize has been claimed, forming the foundation for anyone wanting a completely documented video core on the Pi.

The person to claim this prize is one [Simon Hall], author of the DMA module that’s in the current Raspbian release. Even though Quake III already runs on the Pi, it does so with a closed source driver. [Simon]’s work opens up the VideoCore in the Pi to everyone, especially useful for anyone banging their heads against the limitations of the Pi platform.

You can get your hands on the new video drivers right now, simply by downloading and compiling all the sources. Be warned, though: recompiling everything takes around 12 hours. We’re expecting a Raspbian update soon.

Frozen Pi — An Affordable Bullet Time Recorder

March 31, 2014 by James Hobson 31 Comments

What happens when you strap 48 Raspberry Pi cameras together with nearly half a kilometer of network cables? You get your own bullet time capture rig.

Originally inspired by the unique film effect of the Matrix and an old BBC documentary called Supernatural: The Unseen Powers of Animals, the owner of PiFace decided to try re-creating the bullet time effect himself.

To create the rig they’ve taken 48 Raspberry Pis, each with a PiFace controller board and the standard camera. The controller board allows the Raspberry Pi to be used without a keyboard or mouse, so all the network cables have to do is send a simple code to each pi in order to take the pictures. A simple laser cut wood profile is used to snap them all together into a giant ring.

While 48 Raspberry Pis is a lot, they think this is a reasonable project for a classroom environment — besides, how cool would it be to go to school and film your own bullet time stunts?

Continue reading “Frozen Pi — An Affordable Bullet Time Recorder” →

WS2812b Ambilight Clone For The Raspi

March 26, 2014 by Brian Benchoff 28 Comments

For how often the Raspberry Pi is used as a media server, and how easy it is to connect a bunch of LEDs to the GPIO pins on the Pi, we’re surprised we haven’t seen something like Hyperion before. It uses the extremely common WS2812b individually controllable RGB LEDs to surround the wall behind your TV with the colors on the edges of the screen.

One of the big features of Hyperion is the huge number of LEDs it’s able to control; a 50 LED strip only eats up about 1.5% of the Pi’s CPU. It does this with a “Mini UART” implemented on the Pi running at 2MHz.

There’s only one additional component needed to run a gigantic strip of RGB LEDs with a Pi – an inverter of some sort made with an HCT-series logic chip. After that, you’ll only need to connect the power and enjoy a blinding display behind your TV or monitor.

Thanks [emuboy] for sending this one in.

Monitoring Your Gas Consumption With A JeeNode And A NRF24L01+

March 23, 2014 by Mathieu Stephan 15 Comments

[Sven337] just blogged about a gas consumption monitoring setup he finished not long ago. As his gas meter was located outside his apartment and nowhere near any electrical outlet, a battery-powered platform that could wirelessly send the current consumption data to his Raspberry Pi was required. His final solution therefore consists of a JeeNode coupled with the well known nRF24L01+ wireless transmitter, powered by 3 supposedly dead alkaline batteries.

[Sven337] carefully looked at the different techniques available to read the data from his meter. At first he had thought of using a reflective sensor to detect the number 6 which (in France at least) is designed to reflect light very well. He then finally settled for a magnetic based solution, as the Actaris G4 gas meter has a small depression intended for magnetic sensors. The PCB you see in the picture above therefore has a reed sensor and a debug LED. The four wires go to a plastic enclosure containing the JeeNode, a couple of LEDs and a reset switch. Using another nRF24L01, the Raspberry Pi finally receives the pulse count and reports it to an eeePC which takes care of the storage and graphing.

Prop Replica Tesseract Case Has Some Serious Tech Inside

March 12, 2014 by James Hobson 4 Comments

tesseractpng

[Dustin Evans] is a big fan of the recent Avengers movies — heck, we are too! So he decided to make this awesome Tesseract Case prop replica!

Tesser-what? A tesseract, or cubic prism is a geometric shape that is technically a four-dimensional hypercube — in the Avenger’s movie, it is an incredibly powerful and unstable alien energy source.

To make the replica, [Dustin] picked up a cheap aluminum tool case from the hardware store, took some measurements and began designing the inside of it using SketchUp. He’s crammed in an Arduino with a spectrum shield, a BlueSmirf Bluetooth modem, a Raspberry Pi, a 7″ LCD, speakers and an amp, a WiFi card for the Pi, and a few strips of Neopixels. It is running Raspbian with a stand-alone version of XBMC, which means using AllCast he can wirelessly control the box from a phone or tablet — now all he’s missing is a mini-generator that can put out a few million watts!

Continue reading “Prop Replica Tesseract Case Has Some Serious Tech Inside” →

Smart Kegerator Bills Based On Beer Consumption

March 11, 2014 by Kristina Panos 34 Comments

Kegerator ownership is awesome, but it has its downsides. It’s hard to keep track of who drank what without cans or bottles to count. [Phil] was looking for a good solution to this problem when it came to sharing beer with his roommates and friends and has just completed the first iteration of his smart kegerator.

He has devised a system based on a Raspberry Pi. His software recognizes the face of the person pulling a beer and adds a charge to their tab based on the price of the keg and the volume of the pour. The system also keeps track of current and historic temperature and humidity values inside the kegerator, and everything is displayed on a Mimo 720S touch screen.

[Phil] has a flow meter on each keg to detect and monitor pouring. This triggers the Pi camera module to run the facial recognition. The walk-through found after the jump might be a bit confusing; at the time it was recorded, the unit was only capable of facial detection. [Phil] wrote the UI in QT and C++ and used Python scripts for the flow interrupts. His plans for future iterations include weight sensors underneath the kegs, liquid probe thermometers for more accurate beer temperature readings, a NoIR Pi camera module for low light conditions, and a really snazzy UI that you’ll see on his build page.

If you don’t have a Pi, here’s an Arduino-fied kegerator that reports temperature and controls beer cooling.

Continue reading “Smart Kegerator Bills Based On Beer Consumption” →