WEBVTT 00:00.170 --> 00:01.400 Hi robotic enthusiast. 00:01.790 --> 00:07.640 In this first laboratory lesson of the course, we will create our first Ros two workspace. 00:08.120 --> 00:14.870 As mentioned in the previous lesson, the workspace is just a folder of our PC that will contain all 00:14.870 --> 00:17.750 the packages with all the software for our robot. 00:17.960 --> 00:27.170 So to create a folder, let's open a new Linux terminal and use the command make directory so mkdir 00:27.200 --> 00:33.350 followed by the flag minus P and then we need to specify the name of the folder we want to create. 00:33.350 --> 00:42.560 So let's call this one Arduino bot workspace and let's also create the source folder within this one. 00:42.710 --> 00:44.510 So let's press enter. 00:44.630 --> 00:51.200 And this command has created the Arduino bot workspace folder within our PC. 00:51.950 --> 01:01.320 For now, if we enter in this folder, this is just a folder in our PC that contains another sub folder 01:01.530 --> 01:03.840 that is called SRC. 01:04.290 --> 01:09.720 And here inside the source folder, we will place all the code for our robot. 01:09.720 --> 01:14.490 So here we will add packages that will contain all the functionalities of the robot. 01:14.850 --> 01:21.600 This will be our Ros two overlay where we will have access to all the functionalities and packages of 01:21.600 --> 01:26.280 Ros two as well as all the new packages that we will develop during the course. 01:26.830 --> 01:31.840 Now let's initialize the workspace so that it is recognized by Ros two. 01:31.960 --> 01:38.680 And so all the new packages and code that we are going to insert here will become available and executable. 01:39.330 --> 01:49.020 So back in the Arduino bot workspace folder, let's use the command called con build and let's press 01:49.020 --> 01:49.800 enter. 01:50.140 --> 01:55.140 Call Con is a build tool that converts the source code and the scripts. 01:55.140 --> 02:01.290 So the one that we are going to develop in C plus Plus or Python or any other programming language into 02:01.290 --> 02:08.190 executable files that can be run, that can be executed as normal applications within the system by 02:08.190 --> 02:11.370 running the call con build command inside the workspace. 02:11.370 --> 02:18.030 So inside the Arduino bot workspace folder, it will automatically generate two more folders that we 02:18.030 --> 02:20.550 can see are build and install. 02:20.550 --> 02:23.910 And it also generated a folder called log. 02:24.710 --> 02:29.990 Interest to our workspace is just a folder with a specific structure. 02:30.140 --> 02:31.370 The source folder. 02:31.370 --> 02:37.610 So the SRC folder contains all the source code and the scripts that we are going to develop during the 02:37.610 --> 02:38.270 course. 02:38.420 --> 02:46.250 Then the build folder and the install folders are automatically generated by the build command based 02:46.250 --> 02:47.300 on the content. 02:47.300 --> 02:53.960 So based on the scripts that we are going to insert within the source folder, the build folder contains 02:53.960 --> 03:00.080 intermediate files and creates a sub folder for each package present in the source folder. 03:00.920 --> 03:06.800 The install folder on the other end is the final destination, so each package is installed there in 03:06.800 --> 03:11.930 the install folder and it contains the executable files for our application. 03:12.990 --> 03:19.020 Now that we have created the structure of the workspace, we can proceed with the creation of the first 03:19.020 --> 03:19.690 package. 03:19.710 --> 03:26.160 So the first container of the source code within the workspace, as mentioned before, this package 03:26.160 --> 03:29.820 should be placed inside the source folder of the workspace. 03:29.820 --> 03:37.020 So let's navigate to the source folder and inside this folder to create a new package, we can use the 03:37.020 --> 03:46.560 command Ros2 package create followed by the desired build tool for creating the package. 03:46.560 --> 03:51.540 So let's use the flag build type. 03:51.690 --> 03:57.630 And this build type depends on the programming language that we want to use in this package. 03:57.720 --> 04:06.900 In this case, as we are going to create a package to include Python code, we use the amend Python 04:06.900 --> 04:11.280 build type and then we also need to provide a name for our package. 04:11.280 --> 04:19.630 For example, let's call it Arduino, but Pi examples. 04:19.630 --> 04:21.730 So let's press enter. 04:21.940 --> 04:28.270 And in this package we are going to include some example code, some templates in Python that you can 04:28.270 --> 04:31.630 use as a starting point for creating your own nodes. 04:31.900 --> 04:37.060 Let's also create another package to provide the same template and the same examples. 04:37.060 --> 04:47.920 Also for Cplusplus still with the rescue package, create command and in this case let's use as a build 04:47.950 --> 04:56.710 type the amend CMake since we are going to develop Cplusplus code in this package and let's name this 04:56.710 --> 05:03.690 package Arduino board CP examples. 05:03.700 --> 05:07.450 So let's press enter to create also this other package. 05:07.450 --> 05:13.780 And now if we take a look to the content of the source folder, we can see that now there are two subfolder. 05:13.780 --> 05:21.670 There's the Arduino CP examples and the Arduino bot Pi examples that were created by the Ros2 package. 05:21.670 --> 05:22.780 Create Command. 05:23.020 --> 05:24.730 Now back to our workspace. 05:24.730 --> 05:29.590 We can run again the command called Build. 05:29.830 --> 05:35.680 And now this command will rebuild the entire workspace, including the two new packages that we just 05:35.680 --> 05:36.520 created. 05:36.520 --> 05:43.000 And in fact, you may notice that the output of the build command is slightly different from what we 05:43.000 --> 05:43.900 saw earlier. 05:43.900 --> 05:51.100 And in fact, this is informing us that we have two new packages in our workspace that are Arduino bot 05:51.100 --> 05:54.730 CP examples and Arduino bot Pi examples. 05:56.070 --> 06:02.860 Now we also need to activate our workspace, which means making the Arduino bot workspace folder. 06:02.860 --> 06:07.570 So this one recognized as an overlay for Ros two. 06:07.780 --> 06:14.830 This way, all the packages that we added and that we are going to add in this workspace will be recognized 06:14.830 --> 06:21.790 as Ros two packages and so we will be able to execute their content, their script with the Ros two 06:21.820 --> 06:22.720 commands. 06:23.470 --> 06:31.510 To do this, we need to source a certain file that is located into the install folder that, if you 06:31.510 --> 06:35.290 remember, was automatically created by the build command. 06:35.830 --> 06:40.390 And we need to source the file that is called setup dot bash. 06:40.390 --> 06:46.540 So we can do this by typing dot setup dot bash. 06:46.990 --> 06:52.960 So let's press enter and by doing this we have made the current terminal. 06:52.960 --> 06:56.160 Remember only the current terminal, the one we are using. 06:56.170 --> 07:04.510 And so to aware about the existence of the Arduino bot workspace and actually to verify that this command 07:04.510 --> 07:11.440 has been successfully executed and that Ros2 recognizes the new to package that we have just created. 07:11.470 --> 07:18.340 Let's get the list of all the currently available packages that are available in Ros2 with the command 07:18.340 --> 07:22.420 Ros2 package list. 07:22.420 --> 07:24.470 So let's press enter. 07:24.650 --> 07:31.140 And among them we can see that there are already many packages that were installed by the default Ros2 07:31.160 --> 07:32.090 installation. 07:32.090 --> 07:35.270 And among them if we go to the letter A. 07:37.680 --> 07:45.600 We can see that there is the Arduino board, CP examples and also the Arduino board Pi examples. 07:47.000 --> 07:52.400 This demonstrates that these two packages have been recognized in the Ros two environment. 07:52.400 --> 07:58.700 And so when we will add some code, some scripts to this folder, we will be able to execute and interface 07:58.700 --> 07:59.930 them with Ros two. 08:00.710 --> 08:07.610 However, note and remember that the source command that we used to make the environment aware of the 08:07.610 --> 08:12.290 new overlay only as effect on the current terminal session. 08:12.290 --> 08:17.180 So on this terminal that we have just opened so only applies for this terminal. 08:17.420 --> 08:23.540 So to demonstrate this, if for example, we open a new terminal where we didn't source the workspace 08:23.540 --> 08:35.150 yet, and if we navigate to our workspace now in this case, if we use again, the command Ros2 package 08:35.150 --> 08:35.750 list. 08:36.800 --> 08:41.060 And again, let's scroll to the letter A. 08:42.650 --> 08:50.330 So we can see that the Arduino CP examples and the Arduino Pi examples are not there. 08:51.330 --> 08:54.540 This is a common issue that you need to pay attention to. 08:54.660 --> 09:00.600 Remember that whenever you open a new terminal before using the packages within your workspace, you 09:00.600 --> 09:02.430 must source the workspace. 09:02.430 --> 09:09.580 So namely, you must source the setup file that is located in the install folder of the workspace. 09:09.660 --> 09:19.130 So let's source it also in this new terminal by typing dot install setup dot bash. 09:19.140 --> 09:20.760 So let's press enter. 09:20.760 --> 09:26.700 And now if we run again the command Ros2 package list. 09:27.000 --> 09:29.910 Let's scroll back to the letter A. 09:31.080 --> 09:33.480 Now we can see that also in this terminal. 09:33.510 --> 09:39.510 Roscoe is aware of the existence of the Arduino board, CP examples and the Arduino board Pi Examples 09:39.510 --> 09:40.260 packages.