View source for Pi-puck

=Overview=
<span class="plainlinks">[http://projects.gctronic.com/epuck2/wiki_images/pipuck-overview.jpg <img width=600 src="http://projects.gctronic.com/epuck2/wiki_images/pipuck-overview-small.jpg">]</span><br/>
Features:
* Raspberry Pi zero W (rPi) connected to the robot via I2C
* interface between the robot base camera and the rPi via USB
* 1 digital microphone and 1 speaker
* USB hub connected to the rPi with 2 free ports
* uUSB cable to the rPi uart port. Also ok for charging
* 2 chargers. 1 for the robot battery and 1 for the auxiliary battery on top of the extension
* charging contact points in front for automatic charging. External docking station available
* several extension options. 6 i2C channels, 2 ADC inputs
* several LED to show the status of the rPi and the power/chargers

=Getting started=
This introductory section explains the minimal procedures needed to work with the Raspberry Pi Zero W mounted on the Pi-puck extension board and gives a general overview of the available demos and scripts shipped with the system flashed on the micro SD. The extension is mostly an interface between the e-puck robot and the Raspberry Pi.<br/>

In most cases, the Pi-puck extension will be attached to the robot, but it's interesting to note that it can be used also alone when the interaction with the robot isn't required.<br/>
The following sections assume the full configuration (robot + extension), unless otherwise stated.

==Console mode==
The Pi-puck extension board comes with a pre-configured system ready to run without any additional configuration.<br/>
In order to access the system from a PC in console mode, the following steps must be performed:
# connect a micro USB cable from the PC to the extension module. If needed, the drivers are available [https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers USB to UART bridge drivers]
# execute a terminal program and configure the connection with 115200-8N1 (no flow control). The serial device is the one created when the extension is connected to the computer
# switch on the robot; now the terminal should display the Raspberry Pi booting information
# login with user=pi, password=raspberry


=Operating system=
The system is based on Raspbian Stretch and can be downloaded from the following link [http://projects.gctronic.com/epuck2/PiPuck/gctronic-stretch-ros-kinetic-opencv3.4.1_15.03.19.img.tar.gz gctronic-stretch-ros-kinetic-opencv3.4.1.img.tar.gz].

user/pw: pi/raspberry<br/>
The system starts in console mode, to switch to desktop (LXDE) mode issue the command <code>startx</code>.

When booting the first time, the first thing to do is expanding the file system in order to use all the available space on the micro sd:<br/>
1. <code>sudo raspi-config</code><br/>
2. Select <code>Advanced Options</code> and then <code>Expand Filesystem</code><br/>
3. reboot

==Startup configuration==
The following scripts need to be executed at each startup, alternatively you can set to run them automatically at startup:
* <code>/home/pi/i2c_enable</code>
: this is neeeded to enable the I2C bus
* <code>sudo python3 /home/pi/camera-test.py</code>
: this is needed to correctly configure the camera of the robot

=Robot configuration=
==e-puck1==

==e-puck2==
The e-puck2 robot must be programmed with the following firmware [http://projects.gctronic.com/epuck2/gumstix/e-puck2_main-processor_gumstix_c35e8da_06.11.18.elf  e-puck2_main-processor_gumstix.elf] and the selector must be placed in position 10.<br/>
This is needed in order to exchange data with the robot through I2C.

=ROS=
ROS Kinetic is integrated in the Pi-puck system.
==Initial configuration==
The ROS workspace is located in <code>~/rosbots_catkin_ws/</code><br/>
The e-puck2 ROS driver is located in <code>~/rosbots_catkin_ws/src/epuck_driver_cpp/</code><br/>
Follow the steps in the section [http://www.gctronic.com/doc/index.php?title=Pi-puck#Robot_configuration Robot configuration], only once.<br/>
Follow the steps in the section [http://www.gctronic.com/doc/index.php?title=Pi-puck#Startup_configuration System: Startup configuration], each time the system is powered on.<br/>
The PC (if used) and the Pi-puck extension are supposed to be configured in the same network.

==Running roscore==
<code>roscore</code> can be launched either from the PC or directly from the Pi-puck.<br/>
Before starting roscore, open a terminal and issue the following commands:
* <code>export ROS_IP=roscore-ip</code>
* <code>export ROS_MASTER_URI=http://roscore-ip:11311</code>
where <code>roscore-ip</code> is the IP of the machine that runs <code>roscore</code><br/>
Then start <code>roscore</code> by issueing <code>roscore</code>.

==Running the ROS node==
Before starting the e-puck2 ROS node on the Pi-puck, issue the following commands:
* <code>export ROS_IP=pipuck-ip</code>
* <code>export ROS_MASTER_URI=http://roscore-ip:11311</code>
where <code>pipuck-ip</code> is the IP of the Pi-puck extension and <code>roscore-ip</code> is the IP of the machine that runs <code>roscore</code> (can be the same IP if <code>roscore</code> runs directly on the Pi-puck).

To start the e-puck2 ROS node issue the command:<br/>
<code>roslaunch epuck_driver_cpp epuck_minimal.launch debug_en:=true ros_rate:=20</code><br/>
<!--
To start the e-puck2 ROS node issue the command:<br/>
<code>roslaunch epuck_driver_cpp epuck_controller.launch epuck_id:='3000'</code><br/>
This launch file will start the e-puck2 node and the camera node.
If you are using a PC, then you can start <code>rviz</code>:
* in a terminal issue the command <code>rviz rviz</code>
* open the configuration file named <code>single_epuck_driver_rviz.rviz</code> you can find in <code>epuck_driver_cpp/config/</code> directory
-->

The following graph shows all the topics published by the e-puck2 driver node:<br/>
<span class="plainlinks">[http://projects.gctronic.com/epuck2/wiki_images/ros-e-puck2_.jpg <img width=150 src="http://projects.gctronic.com/epuck2/wiki_images/ros-e-puck2_small.jpg">]</span>
''<font size="2">Click to enlarge</font>''

==Get the source code==
The last version of the e-puck2 ROS node can be downloaded from the git: <code>git clone -b e-puck2 https://github.com/gctronic/epuck_driver_cpp.git</code>

=OpenCV=
OpenCV 3.4.1 is integrated in the Pi-puck system.

==Blob tracking==
A simple demo was developed to track an orange blob. It is thought to be run with the omnivision extension. The robot rotate in place towards the target when it finds one.<br/>
The code can be downloaded from the following repo: <code>git clone https://github.com/e-puck2/e-puck2_pi_blob-tracking.git</code>