Frequent questions

This section explain some common problems and how to solve it!

Installation and compilation problems

  • If you want to change default GCC compiler to version 5, open a terminal and run:
export CC=/usr/bin/gcc-5
export CXX=/usr/bin/g++-5

then you can compile using GCC 5.

Interface problems

  • When I close a node that uses gazebo, it takes too long before it closes.

Answer: You can close manually the process, run in a command window:

sudo killall gzserver gzclient
  • How can I visualize the GPIO state of my raspberry PI 2 remotely?

Answer: You can use pigpio scope [], install piscope in your PC and then run the following command in a terminal.

  • I get error: initInitialise: bind to port 8888 failed (Address already in use)

Answer: This is caused by PIGPIO’s daemon, you can stop all ros process, and kill its process using

sudo killall -9 pigpiod
sudo rm /var/run/

then wait some seconds before it is closed by ubuntu. After thath, you should be able to execute normally.

Other questions

  • How can I monitor the performance of my Raspberry PI 2 or ODROID:

Answer: you can monitor remotely in real-time the RAM and CPU consumption using SSH, open two different terminal windows and run:

watch -n 5 free -m
  • How can I change router configuration?

Answer: You can connect to router, and open a web browser. Type, credentials are: user admin and password admin.

You can, for instance, change static IP address assigned to RPI2, ODROID or PC (DHCP/Address Reservation). As well as checking if all devices are properly connected (DHCP/DHCP Client List)