Thursday, April 24, 2014

The Most Difficult Thing About Raspberry Pi

The most difficult thing about Raspberry Pi is determining which Raspberry Pi project is most interesting to you.  A while back I wrote a Java program to measure my Internet connection bandwidth.  I was thinking it might be a cool project the project over to the Raspberry Pi, write a JavaFX display, and display it like a picture frame on my desk.  Maybe build my own WIFI Pineapple security tool.  I'm still not sure what I want to do but first I need to get the hardware working.

A little background, at my home everything uses the Internet.  I have in the range of 40 to 50 Internet connected devices online at any one time, multiple managed switches, ISP gear, VOIP services, iPhones, solar monitoring, etc.  Do I really really need all this technology?  Nope, not at all but it's just fun to play with.  That is, until I blow up my home network in the middle of my wife's phone call or the kids Netflix isn't working.  The family knows just where to go when the our home IT is not working so keeping my customers happy is important.

For my project I have a basic Raspberry Pi computer and 2.8" TFT display.  I will follow-up with the nuts and bolts of the hardware list at the end of the article.  To begin all Raspberry Pi projects require an image to boot.  If your comfortable with *nix installs then you will feel comfortable setting up a Pi.  Download the Raspberrian image.  Write the image to an SD card.  On OSX, I used the ApplePi-Baker to write the image to an SD card.  My Mac Air just happens to have an SD card slot - whoot!

For me, getting a Pi working was not enough.  I wanted to the get the small 2.8 TFT display working with the Pi as well.  There are some subtleties of the TFT display, and perhaps other TFT displays, to be aware of.  In my case, the screen I'm using uses the GPIO pins so it may not be compatible with other hardware that may use the same pins.  Meaning if you are planning a bigger project there is some reason to to stick to the available composite video port or better yet the HDMI port.  The next concern is the display requires some modifications to the kernel.  All these details are included on AdaFruits web site.  Modifications aside, the results are impressive and the display only uses about 70ma.  Very low power.

After getting the computer and display together and basic testing out the way.  I thought I would try their sample movie and open source animation, "Big Buck Bunny".   It ran pretty well but since my Pi does not have sound I'm missing half the story.  In any case, the animation framerates appear reasonable to the eye.  I notice the movie is optimized for the small display size.  I believe if your using the HDMI port there is hardware acceleration so it's probably a bit more forgiving when playing different movies but I have not tried it yet myself.


Next, I got X-Windows and the desktop working.  Interestingly enough, the screen saver is set by default.  After a few minutes it turned off my screen and I thought the computer crashed.  A quick push to the touch sensitive screen and my computer was alive again - phew!  Of course, it's difficult with my chubby fingers to push small UI widgets on the screen.  Any graphical application you write will have to be optimized to make use of the full screen width and keyboard shortcuts.  For the finishing touches I purchased a PIBOW 3d printed enclosure (on right) that accommodates the screen.  Everything works surpassingly well out of the box and following AdaFruits instructions.  It would be great if the PIBOW case included a smoked acrylic basel but mojo bang for the buck.  Enjoy!

--Milton

My parts list is as follows.

Raspberry Pi Model B 512MB RAM
PiTFT Pibow kit
Adafruit PiTFT - 2.8" Touchscreen Display for Raspberry Pi
32gb SD Memory Card
USB charging cable
Ethernet cable
*Core components purchased from AdaFruit.




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