Today this is not a problem to get a Linux based development board really cheap. Raspberry Pi or Beagle Bone are the first that come to mind. Having those on your desk you wouldn’t think about building one by yourself. Unless you want to challenge yourself. Henrik thought it would be fun to build a Linux board with BGA processor. We all know that soldering BGA at home can be tricky, but doable. So he’s chosen cheap ARM processor with memory management – AT91SAM9N12. It comes in 217 BGA package with 0.4mm balls and distance between 0.8mm. Next to it he added DDR2 RAM which also comes in BGA package.
Another challenge was to find PCB manufacturer which would make small pads and vias reliable and cheap. OSH Park seemed to be right choice. Once boards has arrived, next step was to solder chips and other SMT parts. He applied soldering paste with stencils and placed chips. He had to be careful because even 0.4mm error would cause row offset of ball array. Obviously soldering was done with reflow oven which did job pretty good. Other components like NAND flash and large components were soldered by hand. Then he configures Linux system which had to be loaded in to memory and magical screen appeared. This is amazing what can be done with home conditions and some knowledge today.
Raspberry Pi has everything you need to run as simple Linux computer on your desk. There are USB, audio, HDMI, Ethernet and SD socket. But not all applications require all that connectivity. In most project connectors a taking space. Domipheus has faced the high profile of Raspberry Pi problem. He wanted to build wall mounted Raspberry Pi home server that wouldn’t pop out, and so he started his journey to stripping the board to get it as thing as possible.
As enclosure he intended to use cheap thermostat. It already has mains to 5V built in so the only thin was left – fit raspberry pi and LCD in. He desoldered most of RaspPi connectors including Composite out, audio out, HDMI, camera interface. He used RasPi model A with no Ethernet as he intended to use WiFi for internet access which connects via USB. After stripping all out he was able to achieve 10.5 mm height of Raspberry Pi plus LCD display. To see more pictures of success story follow Flickr.
Raspberry Pi is a great Linux based development board that found its place in hobby market. It’s cheap, have all features required for small computer to be run and there is quite big ecosystem where you can find tons of tutorials, guides and projects. No matter ho good all boards are, we always love new stuff. So here it is – new version of Raspberry Pi called Model B+.
This update is dedicated to layout improvements and extending some of its current features. So in one hand you may be a little bit disappointed because you will find same processor – BCM2835 running at 700MHz and 512RAM. As for processor this is OK because it’s very well understood and adapted. As for RAM 1GB wouldn’t hurt. But who love using this board for prototyping and building stuff should enjoy following improvements. First of all it got rid of sticking out SD card. Its been replaced with MicroSD socket which stays behind the board. GPIO was extended from 26 to 40 pins. First 26 pins are same as in model B. Additional pins mean more direct interfacing to custom hardware. Another waited feature is two additional USB ports. Total four ports should free us from using USB hubs in order to interface peripherals like keyboard, mouse, WiFi dongle and other. It also got rid of Composite video connection which was incorporated in to Audio jack as fourth pin. Other not so visible features include better audio with less noise, lower power consumption with more efficient power regulator. Form factor also changed a bit. It has rounded corners, mounting holes for future adapters. And most important – price hasn’t changed. It stayed as previous – $35.
Raspberry Pi is a great tool for extracting data from the internet. Jacobean has built a weather station where Raspberry Pi pulls data from weather.com and displays it on Adafruit 2.8” touchscreen TFT display also known as PiTFT. Python already has a great module which allows to pull data from several weather services on-line.
Weather display shows current day temperature, barometric pressure, humidity and other information. Also it displays information for several next days. Small graphical icon makes it look more live.