First Steps to Start Working on the Project

  1. Check that your hardware kit is complete.
  2. Check which information is available on this website. Note that it will be updated regularly, stay tuned.
  3. Power up your Raspberry Pi and let it bind to the room's WiFi.
  4. Check you can access it thought SSH on the DICE machines.
  5. Without plugging yet any motor or sensor, build the full electronic wiring.
  6. Create in the home folder a minimal and start the Sandbox.
  7. Check that the Sandbox runs smoothly and that the toddler code is executed.
  8. Now you can start to connect sensors one by one and experiment for each of them what are its capability, noise and limitations.
  9. Connect one motor and make it spin and stop. The same for the servomotor.
  10. Check/observe which legos are available to you as building blocks. Read the resource hints and tricks about legos.
  11. Start the actual design of the robot.


Each Raspberry Pi has been assigned a unique hostname. We decided to name them after Digimons and Pokemons. Therefore, as part of your kit, you should have a Raspberry Pi labeled with one of the following identifiers:

Agumon, Armadillomon, Biyomon, Gabumon, Gatomon, Gomamon, Hawkmon, Meicoomon, Palmon, Patamon, Tentomon, Veemon, Wormmon.

Bulbasaur, Caterpie, Charmander, Clefairy, Diglett, Jigglypuff, Meowth, Pikachu, Psyduck, Rattata, Squirtle.

Connecting The Module

When the Raspberry Pi is powered it will boot-up automatically. The full boot-up sequence takes few seconds, so remember to wait for a short interval before attempting to login to the module. The system will automatically connect to the room's WiFi and be accessible by the DICE machines on the network.

Now you're ready to login to your module. Bring up a terminal window on a DICE machine and use the SSH command to connect to the module. The name of your module will be printed on its top side, for example if the module on your desk is named Panda. So to login to Panda as student you would type ssh -XC student@Panda.

Remember to add the -XC option so that you can later start graphical text editor and debug your image processing remotely. After typing this command you will be asked for a password. The password is password. If all that went well you are now able to login to the module. You should store all your programs in /home/student/ directory. To log out type exit. If you want to reboot or turn off the Raspberry use sudo reboot and sudo poweroff. Always turn off the Raspberry using sudo poweroff, otherwise you may cause damage to the SD card and loose your work.

Step by Step:

Sandbox environment

The sandbox environment is a python program that allows you to develop and run python programs for the Raspberry Pi. The Sandbox handles reading sensors, controlling DC motors and the servo, capturing images from the camera, handling, reporting and logging errors, and launching from the Raspberry.

What is the Sandbox?

The sandbox consist of three python source files located in /urs/local/bin:

The sandbox can be launched by shortly pressing the button connected to the Raspberry. Pressing the button will either start the sandbox or kill all sandbox processes if there are any running. Use the button to start/stop your program during experiments.

The sandbox can also be launched from SSH with the alias commamd: sandbox. This command will start the Sandbox and print the output of the program into the SSH terminal and also display any graphical windows you may have created (e.g. imshow()).

The program will initialize the IO tools (implemented in, start logging, and attempt to import a user program from

Status and error reporting


When running the Sandbox on DICE or on your own machine, the standard and error output will be displayed in the terminal window. However, when you run the Sandbox on the Raspberry, the output streams will be piped into /dev/null to prevent the output from blocking your SSH connection. A copy of these streams will also be saved into a text file: /tmp/sandbox/log.txt. Note that the directory /tmp/sandbox/ needs to be created for the log to be generated.

Any print command or error text will be appended to the end of this file. You can SSH into the Raspberry and retrieve this file. The log file is only temporary and will only exist as long as your robot stays powered. Do not disconnect/turn off your Raspberry if you want to retrieve the log file later.

Uploading Files Onto the Raspberry

You can up/down-loading files to/from the Raspberry via a FTP tool. To do this, you will need:

To upload files via FTP, use the FTP tool of your choosing, specify <host_name> as the server, and student and password as user name and password. This will allow you to modify file in the home directory. You can put the in here.

SSH Into the Raspberry

ssh -XC student@<host_name>

Replacing <host_name> with the host name of your Raspberry. The -XC argument is to allow forwarding of graphical windows (e.g. imshow()). You can now run all the command available on the Raspberry, e.g. sandbox, cp, mv, ...

Using the Supervisor

The Power Button

To use the supervisor script, you should have a button connected directly to the GPIO (General Purpose Input Output) pin 21 of the Raspberry Pi inside the lego case. Normally, this should already be the done for you.

The Supervisor

The supervisor is a script automatically launch by the system when the Raspberry is powered up. It is meant to be use with an external button to start and stop your behaviour ( in a more "autonomous" way, without the need for any SSH connection. With the button: