While working on our latest project with the Raspberry Pi, I was installing various modules on the Raspbian version of Linux, when I was informed that I had run out of disk space. I was confused, because the SD card I was using had 4 GB, and I was sure that the modules I had installed were not that large. It turned out that when you initially flash the SD card, it sets up the root partition as though you have 2 GB free on the SD card. To fully utilize the available space on the SD card, you need to repartition the root drive. Fortunately, that turns out to be very easy with a built-in utility called “raspi-config”. Just type in “raspi-config” at the prompt, and you see the screen pictured at right. Choosing the second option “expand_rootfs” automatically configures the root partition to utilize all available space on the SD card. As I mentioned in a previous post, this utility is also useful for changing the default keyboard setup and timezone if you don’t happen to be from England. I had to do a bit of googling to figure this out, so I hope this post saves someone a little bit of effort.
The Rasbperry Pi is a fully functional cleverly designed microcomputer that you can buy for only $35 (a more stripped-down version will soon be available for $25). The developer’s intent was to design an inexpensive computer to be used by kids in developing countries to learn programming. There has been a great demand by hobbyists, however, who have used it in a variety of projects. I won’t list them all here, but I recommend Googling “Raspberry Pi project ideas” for inspiration. There is a large online community devoted to all things Raspberry Pi related.
As soon as we heard about the Raspberry Pi, my middle son and I were excited to check it out, so we went online and ordered two of them. There are only two online retailers who sell the Raspberry Pi for $35 in the U.S. – Allied Electronics and Element14. If you purchase anywhere else, including Amazon, you’re probably paying a marked-up price from a reseller.
While waiting for our Pis to arrive, I downloaded the Raspberry Pi User Guide from the Amazon Kindle Store (it is also available in paperback) to read up on it. I highly recommend this guide as it gives detailed instructions on setting up your Pi for initial use, and provides links to many online resources.
Last spring I taught an after-school class on LEGO Mindstorms robotics and the NXT programming language at my son’s elementary school. The motivation for the class was to provide a good introduction to LEGO Mindstorms, and I hoped that some of the kids who took the class would sign up for our FLL (FIRST LEGO League) team in the fall.
I worked pretty hard to create a curriculum for the class, and I’m uploading it in case anyone would like use the lessons to teach a similar class. LEGO Mindstorms is a terrific, easily accessible, introduction to robotics, and frankly just a whole lot of fun. One word of advice: If you don’t own a set yet, you might want to wait until the fall, as a new revision, called Mindstorms EV3 will be coming out then.
You can download the curriculum here in Word Document format (large file):
or download it in PDF format:
After completing the Programmable LED Sweatshirt project with the Arduino LilyPad. I was intrigued by the idea of a soft-circuit LED array that could be used as a scrolling message board and general purpose display. With Halloween coming up, my son and I decided to make our own costumes. We came up with the idea of a T-shirt containing an LED array that could scroll messages and display simple graphics.
Once we got the basic LED array working, we decided to add a small joystick to make our project interactive.