Chapter 2. A Raspberry WebIDE Example

In this project, we will learn how to develop projects using the WebIDE from Adafruit Industries. We will flash an SD card with the Raspbian OS, install the Occidentalis tool (https://learn.adafruit.com/adafruit-raspberry-pi-educational-linux-distro/occidentalis-v0-dot-3), set up the web-based development tool, and test the setup using an example.

Note

Occidentalis was initially available as a Raspbian OS image by Adafruit Industries. It comprised of the toolset that enabled to get started with project development using the Raspberry Pi. The OS image was deprecated and released after we finished writing the book. We have taken our best effort to update the book. Please refer to this book's website for more information.

Mission briefing

In this project, we will discuss installing a tool, Occidentalis, and a WebIDE that enables programming in the Python language on the Raspberry Pi. We will also discuss one example from the Adafruit repository and another example of driving an RGB LED.

The following table lists the bill of materials used in this project. These are just examples, and alternative products that have a similar specification may also be used.

Item	Estimated Cost
Raspberry Pi Model B	35 USD
Adafruit Cobbler (https://www.adafruit.com/product/914)	7 USD
Adafruit 7-segment LED Backpack (https://www.adafruit.com/product/879)	10 USD
Blinkm (https://www.sparkfun.com/products/8579)	13 USD

Why is it awesome?

The Adafruit WebIDE in combination with the Occidentalis operating system enables development in the Python language on a Raspberry Pi using just a web browser. It also enables access to sample projects developed by Adafruit via Bitbucket, a source control tool. (If you are not familiar with...

Installation, features, and usage of the Occidentalis operating system from Adafruit

The first step is installing Occidentalis on the Raspberry Pi.

Prepare for lift off

The first step is the installation of the Adafruit-Pi-Finder tool. The tool can be downloaded from https://github.com/adafruit/Adafruit-Pi-Finder/releases/latest. It is available for Windows, Linux, and Mac platforms.

Engage thrusters

1. You can find detailed instructions on installing the Occidentalis tool at https://github.com/adafruit/Adafruit-Pi-Finder.

2. Alternatively, a step-by-step instruction is also available on this book's website. We cannot include them here since changes were made to Occidentalis installation process after we finished writing this book.

Objective complete – mini debriefing

Once the installation is complete, we have to ensure that the Raspberry Pi as well as the development machine are connected to the network via the Ethernet port or a USB Wi-Fi dongle.

Setup of a remote login into the Raspberry Pi

In this section, we will remotely log in to the Raspberry Pi using a secure shell. Since the Raspberry Pi comes with sshd enabled, it is possible to log in remotely using the local name, raspberrypi.local (During the bootstrapping process, the avahi-daemon tool is installed and hence, it is possible to remotely log in to the Raspberry Pi using the local name, raspberrypi.local). Alternatively, on a Windows machine, you can use a tool such as Advanced IP Scanner (http://www.advanced-ip-scanner.com/) to find the IP address of the Raspberry Pi. A snapshot of this tool is shown later in this project.

Note

If you are using a Windows machine, the Bonjour Print Services drivers have to be installed to remotely log in using the local name, raspberrypi.local. The Bonjour Print Services drivers are available from http://support.apple.com/kb/DL999.

Prepare for lift off

The IP address of the Raspberry Pi can be identified using tools such as Advanced IP Scanner...

Installation of the Raspberry Pi WebIDE

We will get started by using a remote login client such as PuTTY to remotely log in to the Raspberry Pi and install the Adafruit WebIDE. In order to get started with examples from the Adafruit repository, we need a Bitbucket account, and Adafruit provides detailed instructions for this at http://learn.adafruit.com/webide/getting-started.

Engage thrusters

1. Once we have logged in, the Adafruit learning system's website recommends executing the following to install the web server:

   curl https://raw.githubusercontent.com/adafruit/Adafruit-WebIDE/master/scripts/install.sh | sudo sh
   

2. It should take about five minutes to finish the installation. If the installation was successful, we should be able to see the message marked in the following screenshot:

   

   Successful completion of the Adafruit WebIDE installation

3. Assuming the installation was successful, we should be able to launch the Adafruit WebIDE using http://raspberrypi.local.

   

   Adafruit WebIDE launched for the first...

Python development on the WebIDE

In this section, we will use a 7-segment LED backpack and the Adafruit Cobbler along with a 26-pin ribbon cable. We will test an example from the Adafruit repository (https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code). In this project, the new add-on hardware that we will discuss is the Adafruit Cobbler. The Cobbler is a small board that aids prototyping circuits on a breadboard. The Adafruit Cobbler costs about 7 USD while the ribbon cable costs about 3 USD and the 7-segment backpack costs about 10 USD.

Note

The earlier mentioned products are merely examples to demonstrate the Adafruit WebIDE. There are alternative prototyping platforms and products available for a higher or lower price.

The Cobbler mounted on a breadboard

Prepare for lift off

In order to get started with the prototyping, the 26-pin ribbon cable is used to connect the GPIO interface to the Cobbler, as shown in the following image. We have to ensure that pin 1 of the GPIO header matches...

Test and debugging examples using the WebIDE

In this example, we will connect the BlinkM to the Raspberry Pi. A BlinkM is an RGB LED that can be connected to your Raspberry Pi via the I2C interface. It is possible to execute light scripts using the port. The connections to the BlinkM are similar to that of the 7-segment backpack.

BlinkM connected to the Cobbler

Note

It is important to pay attention while connecting devices to the GPIO header of the Raspberry Pi. If there are devices that draw a lot of current from the GPIO pins, it may reset the Pi or permanently damage it in the event of a short circuit. It is assumed that you are familiar with basic electronics and capable of handling such devices.

Prepare for lift off

Similar to the previous experiment, we need to determine the bus to which the device is connected using the i2cdetect command. As shown in the following screenshot, the device is connected to bus 1 and the device address is 0x09:

Blinkm connected to bus 1

Engage thrusters

1. The BlinkM...

Mission accomplished

In this project, we worked on two simple experiments using the I2C interface on the Raspberry Pi. The two examples discussed using the Adafruit WebIDE reflect the fact that the tool can help save time for any electronics project involving a Raspberry Pi since it comes with some of the prerequisites installed along with a web interface that just makes remote development easier.

We hope that you had fun taking the Occidentalis distribution for a test drive and find it useful in your projects.

Hotshot challenge

In this project, we used two different types of I2C devices, that is, an LED backpack and an RGB LED. It is possible to connect multiple I2C devices to the same interface. How can this be achieved? How can we identify the addresses of these I2C interface-enabled devices and control them?

Installation, features, and usage of the Occidentalis operating system from Adafruit

The first step is installing Occidentalis on the Raspberry Pi.

Prepare for lift off

The first step is the installation of the Adafruit-Pi-Finder tool. The tool can be downloaded from https://github.com/adafruit/Adafruit-Pi-Finder/releases/latest. It is available for Windows, Linux, and Mac platforms.

Engage thrusters

1. You can find detailed instructions on installing the Occidentalis tool at https://github.com/adafruit/Adafruit-Pi-Finder.

2. Alternatively, a step-by-step instruction is also available on this book's website. We cannot include them here since changes were made to Occidentalis installation process after we finished writing this book.

Objective complete – mini debriefing

Once the installation is complete, we have to ensure that the Raspberry Pi as well as the development machine are connected to the network via the Ethernet port or a USB Wi-Fi dongle.

Setup of a remote login into the Raspberry Pi

In this section, we will remotely log in to the Raspberry Pi using a secure shell. Since the Raspberry Pi comes with sshd enabled, it is possible to log in remotely using the local name, raspberrypi.local (During the bootstrapping process, the avahi-daemon tool is installed and hence, it is possible to remotely log in to the Raspberry Pi using the local name, raspberrypi.local). Alternatively, on a Windows machine, you can use a tool such as Advanced IP Scanner (http://www.advanced-ip-scanner.com/) to find the IP address of the Raspberry Pi. A snapshot of this tool is shown later in this project.

Note

If you are using a Windows machine, the Bonjour Print Services drivers have to be installed to remotely log in using the local name, raspberrypi.local. The Bonjour Print Services drivers are available from http://support.apple.com/kb/DL999.

Prepare for lift off

The IP address of the Raspberry Pi can be identified using tools such as Advanced IP Scanner...

Installation of the Raspberry Pi WebIDE

We will get started by using a remote login client such as PuTTY to remotely log in to the Raspberry Pi and install the Adafruit WebIDE. In order to get started with examples from the Adafruit repository, we need a Bitbucket account, and Adafruit provides detailed instructions for this at http://learn.adafruit.com/webide/getting-started.

Engage thrusters

1. Once we have logged in, the Adafruit learning system's website recommends executing the following to install the web server:

   curl https://raw.githubusercontent.com/adafruit/Adafruit-WebIDE/master/scripts/install.sh | sudo sh
   

2. It should take about five minutes to finish the installation. If the installation was successful, we should be able to see the message marked in the following screenshot:

   

   Successful completion of the Adafruit WebIDE installation

3. Assuming the installation was successful, we should be able to launch the Adafruit WebIDE using http://raspberrypi.local.

   

   Adafruit WebIDE launched for the first...

Python development on the WebIDE

In this section, we will use a 7-segment LED backpack and the Adafruit Cobbler along with a 26-pin ribbon cable. We will test an example from the Adafruit repository (https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code). In this project, the new add-on hardware that we will discuss is the Adafruit Cobbler. The Cobbler is a small board that aids prototyping circuits on a breadboard. The Adafruit Cobbler costs about 7 USD while the ribbon cable costs about 3 USD and the 7-segment backpack costs about 10 USD.

Note

The earlier mentioned products are merely examples to demonstrate the Adafruit WebIDE. There are alternative prototyping platforms and products available for a higher or lower price.

The Cobbler mounted on a breadboard

Prepare for lift off

In order to get started with the prototyping, the 26-pin ribbon cable is used to connect the GPIO interface to the Cobbler, as shown in the following image. We have to ensure that pin 1 of the GPIO header matches...

Test and debugging examples using the WebIDE

In this example, we will connect the BlinkM to the Raspberry Pi. A BlinkM is an RGB LED that can be connected to your Raspberry Pi via the I2C interface. It is possible to execute light scripts using the port. The connections to the BlinkM are similar to that of the 7-segment backpack.

BlinkM connected to the Cobbler

Note

It is important to pay attention while connecting devices to the GPIO header of the Raspberry Pi. If there are devices that draw a lot of current from the GPIO pins, it may reset the Pi or permanently damage it in the event of a short circuit. It is assumed that you are familiar with basic electronics and capable of handling such devices.

Prepare for lift off

Similar to the previous experiment, we need to determine the bus to which the device is connected using the i2cdetect command. As shown in the following screenshot, the device is connected to bus 1 and the device address is 0x09:

Blinkm connected to bus 1

Engage thrusters

1. The BlinkM...

Mission accomplished

In this project, we worked on two simple experiments using the I2C interface on the Raspberry Pi. The two examples discussed using the Adafruit WebIDE reflect the fact that the tool can help save time for any electronics project involving a Raspberry Pi since it comes with some of the prerequisites installed along with a web interface that just makes remote development easier.

We hope that you had fun taking the Occidentalis distribution for a test drive and find it useful in your projects.

Hotshot challenge

In this project, we used two different types of I2C devices, that is, an LED backpack and an RGB LED. It is possible to connect multiple I2C devices to the same interface. How can this be achieved? How can we identify the addresses of these I2C interface-enabled devices and control them?