Hands-On ROS for Robotics Programming

Forcing the HDMI output and screen layout

For debugging purposes, it is useful to make sure that you can always access the Ubuntu Mate desktop from a screen, even though the system does not start with it. In order to achieve this, you have to modify the configuration options of the Raspberry Pi:

$ sudo nano /boot/config.txt

The content of the file will be accessible on the screen. Uncomment the following lines, setting the shown values:

hdmi_force_hotplug=1hdmi_group=2   hdmi_mode=47

The last two lines enforce the following display: at 1440 x 900 at 60 Hz. If you want to increase this to full HD resolution (1080 px), then you can do so as follows, depending on the refresh rate:

• For a 50 Hz monitor, use the following:

hdmi_group=1hdmi_mode=31 ...