WEBVTT 00:00.110 --> 00:05.960 There is one more thing I wanted to add in this section, which I think is quite important. 00:05.960 --> 00:11.600 So basically what to do if the cell communication can't be established. 00:11.900 --> 00:18.860 So let's say you have something like uh, this is the wrong port or the Arduino is not connected. 00:18.890 --> 00:27.500 You run the script and you have this error with so huge stuff with basically serial exception could 00:27.500 --> 00:32.120 not open port okay or something that is similar. 00:33.280 --> 00:40.030 Well, in this lesson, I'm first going to go through the different things you can do to debug, and 00:40.030 --> 00:45.100 then you will see how to make your Python program automatically retry to connect. 00:45.100 --> 00:49.270 So here to the Arduino when it fails the first time. 00:49.270 --> 00:49.600 All right. 00:49.600 --> 00:51.310 So let's start with the debugging part. 00:51.310 --> 00:58.420 First of all make sure of course that your Arduino board is correctly plugged to your Raspberry Pi with 00:58.420 --> 00:59.440 the USB cable. 00:59.440 --> 01:04.930 Okay, that sounds quite obvious, but it has happened to me a few times that I was like, why is not 01:04.930 --> 01:05.380 working? 01:05.380 --> 01:09.190 Well, if you look on the side, the Arduino is not connected, that's why. 01:09.220 --> 01:15.760 Okay then of course, make sure that you have the correct port here that you can check on the terminal. 01:15.760 --> 01:25.060 So with um lhs slash dev slash tty like this and check the port is here. 01:25.060 --> 01:29.110 So you can connect, disconnect and find what is the difference in here. 01:29.110 --> 01:30.460 You're going to find this port. 01:31.150 --> 01:31.720 Make sure. 01:31.720 --> 01:33.550 Also you have the same baud rate. 01:33.670 --> 01:34.270 Okay. 01:34.950 --> 01:40.260 Well, if you have a different baud rate, the communication is gonna be opened anyway, but then everything 01:40.260 --> 01:42.600 is gonna not work, basically. 01:42.630 --> 01:45.330 Also, wait a few seconds, okay? 01:45.330 --> 01:50.820 After opening the communication so you don't get any garbage and reset the input buffer. 01:50.820 --> 01:56.100 So you start here the while loop with a fresh input buffer on the Raspberry Pi. 01:56.100 --> 02:02.760 And then when you run your program, well, if you are currently, for example, uploading the program, 02:02.760 --> 02:05.220 let's let's say use the serial monitor here. 02:05.220 --> 02:09.000 So I have the monitor which is a cell communication with the Arduino. 02:09.630 --> 02:10.080 Okay. 02:10.470 --> 02:13.500 On this pot you can see on this pot now I'm gonna run. 02:15.090 --> 02:18.060 The script, you can see we have the same error. 02:18.060 --> 02:21.210 Well, actually we don't have the exact same error. 02:21.210 --> 02:25.380 We have the error that says device or resource is busy. 02:25.530 --> 02:26.130 Why? 02:26.130 --> 02:29.790 It's busy because we are currently using the serial monitor. 02:29.790 --> 02:32.700 Or maybe we are currently uploading a code. 02:32.730 --> 02:40.020 Okay, so if I close the serial monitor and if I run again now, it's going to work. 02:40.050 --> 02:40.530 Why? 02:40.560 --> 02:43.200 Because the serial is actually free. 02:45.200 --> 02:50.000 So make sure you have only one program at a time that is using cell communication. 02:50.000 --> 02:52.730 So that can be uploading the sketch here. 02:52.730 --> 02:57.290 That can be using the sign monitor or that can be using the Python program here. 02:57.770 --> 02:58.190 All right. 02:58.190 --> 03:04.010 And one more thing also is of course make sure that uh, the program here is correctly uploaded to the 03:04.010 --> 03:04.670 Arduino. 03:05.000 --> 03:11.480 Don't forget to upload it before you try to communicate with it and make sure you have this line. 03:11.480 --> 03:11.780 Okay. 03:11.780 --> 03:12.830 So let's begin. 03:13.250 --> 03:13.490 Okay. 03:13.490 --> 03:17.810 If you don't begin this here on the Arduino anyway, that's not going to work on the Raspberry Pi. 03:17.960 --> 03:22.430 So well basically if you respect all of that it should work fine.