Tag Archives: Linux

Beaglebone Black LESSON 3: Running Python on Your Beaglebone

In this series of lessons, we will be controlling the GPIO pins from Python. If you do not already have a Beaglebone Black Rev. C, you can pick one up HERE.

In this lesson we show you how to write and run a simple Python program. Be sure to go through LESSON 2, which shows you how to boot and remotely connect to the Beaglebone. You will need to know how to do that for this lesson.

Raspberry Pi Linux LESSON 25: Raspberry Pi 2 Pinout

In our earlier lessons we have taken you from installing the operating system, all the way through creating and running your first python program. At this point, you know how to generally operate the Raspberry Pi platform. Now we are ready to start building projects, and getting the Pi to perform for us. The first thing we will need to understand is which pins do what. The pi has many pins, so the diagram below shows what each pin can do.

Raspberry Pi 2 Pinout
This figure shows the Raspberry Pi GPIO pinout

In order to understand pin number, make sure to have your pi oriented as shown in the figure.  Now look at the center two columns on the chart. These show you the physical pin number. The outer two columns of the chart show you the bcm  numbering. Which numbering system you use depends on how you configure things in the software. We will cover this in the next lesson, but for now know there are two different numbering schemes. For the examples in this series of lessons we will use the bcm numbering scheme, so we will be using the number references in the outer two columns.

Also notice that some of the pins are multi-purpose. For example physical pins 3 and 5 can be GPIO pins, or they can be configured for I2C. Similarly, 8 and 10 can be general purpose GPIO pins, or can be Tx and Rx.  Note the GPIO pins are analogous to your digital input/output pins on Arduino (the ones without the ~ by them).

In general when setting up a project I try and select GPIO pins that are not multi-function. In this way if I ever expand the project and want to add Tx/Rx or I2C capability, those pins are still free.

Raspberry Pi Linux LESSON 23: Changing File and Folder Permissions

In this lesson we look at changing file and folder permissions. In the earlier lessons we learned that we can view the file and folder permissions by navigating to the folder of interest, and then giving the ls -l command. In order to change the permissions, we will use the chmod command. This video explains how to use the chmod command to control who has what permissions.