WEBVTT 00:00.360 --> 00:07.100 This is the solution of the previous activity where you need to complete the duration of this line, 00:07.110 --> 00:14.230 so the line with the false information, you need to know basically how long this line takes to execute. 00:14.910 --> 00:23.790 So you can see here first we call this function already here in the void loop every one hundred milliseconds. 00:23.790 --> 00:30.020 So every 100 meters that we trigger the ultrasonic sensor and then we call the function to get the distance. 00:30.390 --> 00:32.490 And in that function, we call those in. 00:32.520 --> 00:36.660 So that means we can directly measure the time right here. 00:37.020 --> 00:47.300 So what I'm going to do and we unsigned long time making, which is I couldn't use means I can use micros, 00:47.310 --> 00:49.920 OK, if I want to be more precise. 00:50.400 --> 00:53.240 So I get the time before the action. 00:53.670 --> 00:54.600 I do the action. 00:54.990 --> 00:55.890 I get the time. 00:58.660 --> 01:05.530 The actual time and make sure if you use macros that you use micros here and if you use minutes you 01:05.530 --> 01:09.280 use Moelis, you want to compare things that can be compared. 01:09.520 --> 01:15.040 Now, I'm going to sign long that's called it's called duration. 01:15.940 --> 01:19.300 And that would be time and minus time. 01:21.040 --> 01:26.680 So I'm just making the subtraction between the time after the action and the time before the action, 01:26.680 --> 01:29.480 which gives the duration of the action basically. 01:30.100 --> 01:33.250 And now what I can do is say that let's do say a print. 01:34.530 --> 01:35.250 Duration. 01:37.120 --> 01:43.090 And say of print and then with code duration viable. 01:45.120 --> 01:53.200 So every time we go to a new line to what will happen here is that first, so we call the function that 01:53.250 --> 02:00.360 we execute the action, the functionality doesn't change here, that we add a new piece of code, that 02:00.360 --> 02:02.580 we complete the duration in print the direction. 02:02.880 --> 02:06.830 Then we return the distance and we print the distance, we say of the printing. 02:06.900 --> 02:09.880 So we will first get the duration and then the distance. 02:10.200 --> 02:10.610 All right. 02:10.620 --> 02:11.660 And now let's. 02:12.390 --> 02:13.710 So it's the fire code. 02:13.890 --> 02:16.800 I have named this activity in 14. 02:16.950 --> 02:22.050 OK, and let's upload the code to Jeronimo. 02:23.800 --> 02:28.990 But make sure they are connected and know I am going to open the sale Moniteau. 02:30.430 --> 02:32.080 And let's see what we get. 02:32.280 --> 02:40.630 OK, you can see we still have the distance in centimeters, so I have here one hundred thirty seven, 02:40.630 --> 02:45.150 eight centimeters and the duration of the pulse in function. 02:45.160 --> 02:52.630 So the total duration of this line of code, which is here eight thousand five hundred, which means 02:52.630 --> 03:01.960 that here, between this point and this point, you have eight point five milliseconds that we're used 03:01.960 --> 03:05.340 by this function, which is actually quite a lot. 03:05.350 --> 03:05.640 No. 03:06.430 --> 03:08.030 OK, let's make some experiments. 03:08.230 --> 03:13.900 Now I'm going to put my hand in front of the sensor so you can see we have 10 but 10 centimeters. 03:15.070 --> 03:19.780 So the shorter the distance, well, the shorter also the duration. 03:19.830 --> 03:27.490 OK, you can see now if I increase, the distance increases and the duration also increases and I remove 03:27.490 --> 03:27.940 my hand. 03:27.970 --> 03:29.200 This is the wall behind me. 03:29.720 --> 03:31.810 So I have eight point five thousand. 03:32.080 --> 03:36.800 I'm going to move this a little bit so I can maybe increase the distance here. 03:36.880 --> 03:47.560 I have 220 centimeters OK here and I got about 13000 microseconds. 03:48.070 --> 03:54.270 OK, which means that for 200 centimeters, dysfunction will take 13 milliseconds. 03:54.280 --> 03:55.990 And this is not even the maximum. 03:55.990 --> 04:01.570 The maximum is four hundred centimeters, which means that I don't know exactly, but this will take 04:01.570 --> 04:04.760 between 20 and 25 milliseconds. 04:05.230 --> 04:09.630 OK, the person we rate for 20 to 25 milliseconds. 04:10.000 --> 04:11.220 So what is the problem here? 04:11.230 --> 04:17.970 The problem is that, well, previously with the time functionalities, we have removed all of the delays. 04:17.990 --> 04:23.050 OK, so the problem is not stuck and we can make multiple actions run in parallel. 04:23.200 --> 04:27.050 And we also don't miss any data and we can have a more efficient code. 04:27.370 --> 04:33.370 Well, as you can see here with the both in function, it's just like we've added the delay back in 04:33.370 --> 04:40.630 our code, because if there is not oxygen, the person will take 25 milliseconds to execute between 04:40.630 --> 04:47.500 20 and 25, which is if you compare to how frequently we call that here, we call that every one hundred 04:47.500 --> 04:48.220 milliseconds. 04:48.730 --> 04:56.400 So every 100 milliseconds we are going to spend up to twenty five milliseconds just with this line. 04:56.800 --> 05:03.160 So we are going to wait 25 percent of the computing time of the original, which is well, actually 05:03.160 --> 05:09.310 quite a lot because now imagine that you don't have one since like this, but you have four sensors 05:09.310 --> 05:12.830 like this, which is actually a real case in real robots. 05:13.420 --> 05:18.130 So if you have false insults and you wait for twenty five milliseconds each, well, you're going to 05:18.130 --> 05:23.980 have some problems because all the time will be spent waiting in the person. 05:24.640 --> 05:31.150 So you can see this is really, really useful to measure the duration with this technique. 05:31.200 --> 05:32.920 OK, you can easily spot. 05:32.930 --> 05:38.500 So if you have a dog here, I have of course given you the exact line to check. 05:38.650 --> 05:45.640 But if you have a doubt, you can just do this and maybe maybe your dog is unfounded and and you have 05:45.640 --> 05:50.680 a problem somewhere else, but maybe your dog is funded and you find that one line is just taking so 05:50.680 --> 05:54.230 much time to execute and that is a burden for your program. 05:54.820 --> 05:59.860 So now that we know this takes too long to execute well, what can we do about it? 06:00.220 --> 06:05.830 In the next lesson, I'm going to show you simply how to get the same functionality that without the 06:06.040 --> 06:09.520 same function and using Interent.