My Raspberry Pi

Raspberry Pi

This is a computer, really, and a surprisingly good one at that considering the size and price. It's about 4 inches long and they sell for about $45, runs about 2 watts of electricity. At this point it only runs Linux but there's some discussion about a version of OpenBSD that will run on it. There's plenty of discussion at http://www.raspberrypi.org but go to froogle.com and enter Raspberry Pi then search to find good places to buy one. When I bought this a lot of places didn't actually have any in stock.

The cables connected to the board, clockwise from lower left are a mini-USB for power, an RCA plug for composite video, a stereo headphone plug, a single USB cable going to a USB hub, an ethernet connection and an HDMI connection. The gray ribbon cable coming out near the lower right corner is for the official camera ($25). Video and audio output can be changed in a configuration file to enable either the HDMI or the RCA and headphone jack. The camera is surplus from some cell phone and is 5 megapixels, can do both stills and video, it's on a little board about 1 inch square. There's no hard drive for this: permanent storage is an SD memory card, use at least 8 gigs. I bought a 32 gig preloaded with Raspbian for not much more than a blank one. I've filled about 16% of it so far and I'm not being careful to delete old files. Search with Froogle and you'll find some.

The recommended Linux at least for beginners is a variant of Debian called Raspbian and I continue to be impressed by it. As computers go it isn't terribly fast and it only comes with 512 megs of RAM but I've had it a couple of months and installed a bunch of software which all runs, if not very fast. I have Debian on an Intel box as well and this seems to have almost the whole set of about 32,000 programs available for it that's available for the Intel machine. While I'm typing this I'm downloading Tesseract, an OCR (Optical Character Recognition) program for turning scanned text images back into text. I've got Firefox, The Gimp, NEC (antenna simulation), SANE (scanner program), TightVNC, The Arduino IDE, XFig, Etherape, and a whole bunch of other stuff installed. It isn't fast running Tesseract but it works very well compared to the older gocr. The fancy Synaptic package manager program can be installed using a command like "apt-get install synaptic" but I'm finding apt-get to be quite good and surprisingly robust even over an unreliable modem connection. If you do this, start with "apt-get update" which updates the program database, then "apt-get upgrade" which updates any installed software. I didn't do this and later had to upgrade 200 megs of software I already had installed (20 hours by modem). If you buy the camera you'll need to do an upgrade to make it usable so it's much less painful to do this in the beginning. Periodic updates and upgrades are a good idea, but especially running update before you install anything so you get the latest version.

Linux people seem to have a phobia (maybe rightly so) about being logged in as root (the superuser) but I've been doing it under OpenBSD for 15 years or so. The root password is unknown and unpublished but that's simple to fix. Just be logged in with the standard account and do "sudo su" to give yourself root priviliges then "passwd" to change the root password to something you can remember.

The window manager (Openbox) that comes installed as standard in Raspbian looks and works very much like Windows. It can be replaced.

screenshot
You click the strange symbol (you can replace it) in the lower left for a menu like a Windows Start Menu. You can add what amount to shortcuts to the bottom bar. It comes set for 2 desktops but you can change that. This is a screenshot of the Pi running through a VNC connection from another computer. The program running in 2 windows is xnecview showing an NEC simulation of an antenna visible in the left window as blue lines behind the red radiation pattern. This image is a GIF with a reduced number of colors so things don't look quite realistic, it was originally only intended to show the xnecview screens.

I sit here watching apt-get work and trying to figure out what it's doing. It seems to put all the files it needs to get into a queue (there may be hundreds of them). Any that are incomplete at the end of the session because the connection dropped stay in the queue and get resumed next session, but I don't think any partial transfers are being discarded because they didn't finish. If you need to interrupt it just hit Ctrl-C and it will resume starting with the first incomplete file in the queue when you restart. That's the way I'd write it too. Another thing is that the estimate of how much is left to download goes in jumps by sizes of full packages. I had it jump from 100 megs down to 60 at one point.

One of the fun aspects of the Pi is that it's mostly independent of your main computer except for needing an ethernet connection and needing to "borrow" a video monitor, a USB mouse and keyboard and space to put them. You can play around with Linux on this and still leave your main computer unaffected. I don't have room on my desk for an extra monitor, keyboard and mouse so I use a VNC connection over Ethernet to the Pi and access it in the window above from an OpenBSD machine most of the time. You can get VNC client programs for Windows and Mac too.

Pi camera

And this is the official camera, on the other end of the ribbon cable in the first picture. It's also possible to use a USB webcam but the Pi's circuit board was designed with a socket that this plugs into. This camera wasn't available when the Pi first came out, which is why I need to upgrade my Raspbian.

Watch out for versions of things if you buy. There's a revision A of the Pi that only has 256 MB of RAM, and I think versions within that. If you buy a preloaded SD card look at what version of software is loaded onto it. There's no provision for adding more RAM so look for at least a revision B Pi which has 512 MB.


After several nights of downloading I got some pictures out of it. This is fixed-focus so these aren't quite in focus. Also there's only one overhead lightbulb so the lighting wasn't very good and I tweaked the levels in The Gimp.

4/1/2014: I still like it. Mostly I use it because it has ghotofs, which is how I transfer pictures off my Nikon Coolpix P520, which pretty much only runs under Linux. Also xnecview still works better here than under OpenBSD. I still haven't bought a dedicated display for it, I ssh to it, or use it via a VNC connection from OpenBSD machines. I'm thinking of a use where I've got a USB WiFi adapter which, once I build a reflector for, I may be able to hit an open AP, then I'll want the Pi as a router. The speed? I've gotten used to it. I think it would make a good kid's first computer instead of having them brainwashed by Microsoft junk. With the Debian system, programs to do almost anything that can be imagined are free for the installing. There's a great emphasis on education rather than profit. I can buy some cheap Android tablets for the price of a display for this though, so I don't know.

5/15/2014: Thinking about buying a second one for upstairs. I just added a PiTFT display board from Adafruit for $40, which has a touchscreen and backlight. It looks like a real monitor in miniature but it's readable from a few feet away. About the same size as the Pi itself, it plugs into the GPIO connector but extends it so you can plug more things in. With a USB mouse and keyboard plugged in it's a complete computer.

ABIJX / toys