As a reminder, CMU Computing Policy requires maintaining the confidentiality of your Andrew account credentials.  As such, it is not acceptable to store your Andrew ID and password on embedded devices such as Raspberry Pis.

For these devices, rather than using the “CMU-SECURE” network, which requires your credentials be stored in your network configuration, we recommend you use the Network Registration System (NetReg) to register the MAC address of your device and connect via the “CMU” network instead.

To add a cron job, type nano crontab -e into the terminal. A job is formatted as such:

minute hour day month day-of-week command-line-to-execute


You must use this order, and you may not have any missing fields. The acceptable values for each field is as follows:

You may also use *, a wildcard character for any given category. This indicates every possible value for the field. So, if you wanted to run a command every day at 1:20pm, your time portion would look like this:

20 13 * * *

Note that we’re using “13” instead of “1” for the hour slot, because we’re using a 24-hour clock. If you wanted to run something every five minutes, you would simply do:

*/5 * * * *

Using the slash, we can divide the wildcard symbol by any number, causing the job to run whenever it’s evenly divisible. And if you’d like to run a script every Friday the 13th at 11:11am and 11:11pm (usually lucky times, even on a very unlucky day), you’d simply write:

11 11,22 13 * 5

Note the hour field–we can select a set of specific times by separating different values with a comma (with no spaces)!

These instructions are rough and should be updated as the system evolves.

1. Follow the standard directions to download and boot a Raspbian image. See http://www.raspberrypi.org/downloads/ and http://www.raspberrypi.org/help/
2. The Pi needs to be connected to a monitor and keyboard for the very first boot in order to respond to some one-time initialization prompts.  After that, it can be operated solely as an ethernet device if desired.
3. The Pi will need to be brought up to the point where the internet is accessible, either plugged into a local network, or sharing the network via another computer.
4. The general instructions for the courseware update system install are here: https://github.com/cmuphyscomp/pi_puppet/blob/master/README.md
5. Update the package system index and do a general upgrade of all packages:

   sudo apt-get update
   sudo apt-get upgrade

6. The courseware update system uses the ‘puppet’ package. To install:

   sudo apt-get install puppet

7. To install the update system:

   cd /etc/puppet/modules
   sudo git clone https://github.com/cmuphyscomp/pi_puppet
   

8. Run the update script once in-place for initial configuration:

   sudo python /etc/puppet/modules/pi_puppet/files/bin/pi_update
   sudo apt-get clean

9. After the initial configuration, full updates can be performed as follows:

   sudo pi_update

10. The /opt/cmuphyscomp folder contains a package of source code and binaries.  The source code is checked out from public Internet sites, some binaries are compiled on the Pi itself, some binaries are downloaded.  To recreate or update this folder, run the following script:

    sudo setup_cmuphyscomp

11. Note that the previous setup script also creates files in /usr/local.  This means that the best way to duplicate the system is to take a full image of the SD card; the contents of /opt/cmuphyscomp are not quite enough.
12. The /opt/openFrameworks folder contains an openFrameworks installation for writing C++ graphics and vision programs and is intended for advanced users. To recreate or update this folder, run the following script, which can take an hour or more:

    sudo apt-get clean
    sudo setup_openframeworks

** if you change the image on your SD card, you may need to re-register your machine on the wifi network.