In earlier lessons we showed you how to remotely login to your Raspberry Pi using the putty SSH program. This is great for many things, but sometimes you would like to have the full Raspberry Pi graphical desktop available from a remote computer. In this lesson we show how to run the Pi Graphical User Interface remotely. The software is TightVNCserver, and it really works great. The video above steps you through installing and running the software.
I really hate having to double click on icons or programs to get them to open. This lesson is a quick one, but explains how to get your Raspberry Pi to open files, folders and programs with a single click of the mouse. To do this boot the Pi in the Graphical Interface. Then click on the file cabinet icon to get a folder to open. Then under Edit select Preferences. Then check the box that says “Open Files with Single Click”. Done!
Now that we are booting in the Graphical User Interface on the Raspberry Pi, we can explore some useful applications that will run on the Pi. LibreOffice is a free product that will do many of the things Microsoft Office does. This is a great addition to your Raspberry Pi. You can install this product by going to the terminal window, and at the command prompt on your Raspberry Pi type:
$ sudo apt-get install libreoffice
Now the new software should show up under your menu button. The video above steps you through some of the cool features of the product.
If you have been following along in these lessons, we have been operating from the terminal window and the Linux command line. You have learned that you can simply and efficiently do whatever you want from the terminal window. Raspberry Pi does, however have a graphical interface. In this tutorial we show you how to boot in the graphical interface, and then how to find your way around.
At this point we have learned how to write digital values to the GPIO pins, we have learned to simulate analog out using PWM, and we have learned how to do digital reads from the pins. If you are like me and came from the Arduino world, then you will likely be asking, “Now what about analog reads”. The arduino has pins A0-A5 that make quick and easy work of reading analog values from things like photometers, sensors and various other circuit elements.
The bottom line is, unfortunately, there are no analogous capabilities on the Raspberry Pi. There is no way to directly read analog voltages.
Some suggest incorporating various analog to digital converter chips into your circuits requiring analog reads. For me, my preferred solution is the simply add an Arduino to the Raspberry Pi circuit. There are many very small form factor versions of the Arduino. For example, the nano is very small, and there are some examples that are even smaller. Some of these small implementations can be found for under $10.
If you take this approach, then all you have to do is learn how to communicate between the Raspberry Pi and Arduino either over USB or over ethernet. I show you how to do both of these things in the Lesson series on this WEB site “Using Python with Arduino”. This shows how to communicate between python and arduino using the USB, using Ethernet, or using the Xbee radios. Since python runs on the Raspberry Pi, all the techniques taught in those lessons can be applied to the raspberry pi.
In our high altitude balloon instrumentation package, we actually run a raspberry pi that is controlling two arduino nano microcontrollers. The one arduino is controlling the 9-axis IMU, and the other arduino is running GPS, Temperature, Pressure, and other sensors. The raspberry pi and Arduinos communicate over a small onboard Ethernet switch. The system communicates back to the ground via 1 watt ubiquity bullet radios.
So, the Raspberry Pi should not be viewed as a replacement for the Arduino, it should be viewed as a complementary device that can work nicely alongside the Arduino.