Computer monitor is pretty strict device – is displays information withing its frame. Outside and behind its dark. To change that Sebastien has been working on several versions of SlightBox projects where it allows playing light effects behind screen that extends on-screen effects and somewhat removes limits between screen and outside world.
Video demonstration speaks for itself. Watching movies and playing games become different with those effects. The heart of this system is Raspberry Pi which does video signal analysis and determines color pixels from captured frames. Python script uses OpenCV library to do this task. Once color data is gathered, it is sent over SPI to LPD8806 LEDs behind screen. Since analyzing HDMI signals is quite tricky, he split HDMI signal where one was converted to S-video which then was fed to Raspberry Pi with STK1160 adapter. Raspberry pi also has a standard LCD for fast control and monitoring parameters. Infrared channel allows remote control of SlightBox. Raspberry Pi also allows configuring devices via web interface. So this is fun device that vivid and extend any HDMI screen at your house. Fun guaranteed. (translated source)
Raspberry Pi is great for doing crazy setups. Being Linux based platform it can take photos, send emails and other messages over internet. Deddies Lab have shared his interesting setup, where he placed a webcam at the front door and when someone pushes doorbell message with photo footage is sent. First of all he hacked in to wireless doorbell where he was able to capture button press with Raspberry Pi GPIO. Then he wrote a simple Python script to send push message with date and time on event.
During building there came a thought that seeing message isn’t enough as there is no info on who was at the door. The next thing he added was Logitech C270 webcam which was configured to capture snapshots and short movies. Again, python script composed email message with images and videos attached. From this point you could start your own modifications of this system. First of all replace webcam with Raspberry Pi camera and have even more options in capturing images and videos. You could expand functionality by adding motion detector and capture images even when someone is walking around (Actually this is already a security system) or you can think of your own options to it.
Hobbyists love Linux powered development boards, because they give lots of flexibility, network connectivity and other benefits OS can give. Linux driven development boards are great, because they already have I/O pins to interface physical world and build project at different level. Market already have over dozen great Linux-based development boards and sometimes you may get stuck thinking which is best to start with. We all are familiar with Raspberry Pi, but don’t get excited, and think your needs first before purchase.
Tony Dicola, recently have made a comparison of four common Linux-based development boards: Arduino Yun, Beaglebone Black, Intel Galileo and Raspberry pi. He listed most of their parameters in to table so you could clearly compare them side by side. Then he takes to next part – performance test. He runs nbench tool, which was developed to measure performance of Pentium class computers. It is obvious even from parameter list that Beaglebone black and Raspberry Pi takes leading positions. Also he measures power usage when idling and running benchmark Raspberry Pi model A leads by maxing at 150mA. While Intel Galileo stands between 500 – 600mA. Other test include CPU temperature measurement, where Raspberry Pi shows best results and Galileo worst. Hardware is worthless without software support and tools, Tony goes through available packages, and support. After comparison it is always hard to tell which one is generally best. Each board brings some value to the bucket. For instance Arduino Yun is great for Arduino compatibility and WiFi, Raspbery Pi is great for learning Linux as it has large community and is cheapest board from the list. Beagle bone gives more I/O and gives more real-time control.
For quite long time Raspberry Pi was the only platform that was using BCM2835 processor. But recently it started selling it to anyone that opened gate for Rpi clones. So it seems that one of the first ones is ODROID-W miniature board. It is compatible with Raspberry Pi in several ways. Forst of all it carry same GPIO layout for connecting existing modules. Of course it doesn’t have pinheaders soldered to keep it’s initial profile low. It features same processor and memory as Raspberry Pi, so it can run any Rpi OS. Being small size allows it to be used as wearable electronics.
To make things more easy, there are several additions made. First of all it has Li Polymer battery connector. Also board includes RTC chip with backup battery connector as well. To keep low profile there is no Ethernet connector, the HDMI port was replaced with Micro HDMI. It still has camera interface, but no display interface which still doesn’t have its module. The list continues with built in DC/DC step-down converter also with DC/DC step-up converter for 5V rails. There is also couple ADC inputs included that were so needed in Raspberry Pi (Actually comes with RTC RC5T619 IC which also is a Li-ion charger). Continue reading