WEBVTT 00:00.330 --> 00:03.690 So now what is the problem with delay? 00:04.140 --> 00:10.400 We're going to come back to the solution of the previous activity when we used the cell communication. 00:11.140 --> 00:17.160 So that is activity number eight going to open that code here. 00:18.630 --> 00:19.810 And go back to here. 00:19.830 --> 00:25.740 So I have provided a few explanation already on the solution for the activity, but I'm going to give 00:25.740 --> 00:30.420 more details now than I understand clearly what DeLay does. 00:30.870 --> 00:36.660 DeLay will simply stop the execution of the program for a certain amount of time. 00:37.350 --> 00:43.380 And in this program, you have seen that when we are in the delay, well, we can't actually do anything 00:43.380 --> 00:43.840 else. 00:43.860 --> 00:46.380 OK, so here we decided communication. 00:46.710 --> 00:52.680 When you send cellular data from your computer to the you know, the hardware of the area will actually 00:52.700 --> 00:56.520 receive the data and it will be ready to be passed. 00:56.580 --> 00:59.310 OK, but because you use a delay. 00:59.700 --> 01:07.240 Well, if you use a delay for here four thousand milliseconds, then the thing is that if you receive 01:07.500 --> 01:13.740 any data before the end of the delay, you will have to wait for the end of the delay to actually be 01:13.740 --> 01:15.390 able to process the data. 01:15.780 --> 01:21.960 So what does this means is that if you use the delay function, basically you can just do one thing 01:21.960 --> 01:22.440 at a time. 01:23.100 --> 01:30.180 If you try to do two things like here blink an energy and the data from the sale, well, you can say 01:30.180 --> 01:36.330 you have a timing problem because you are not able to read the data as soon as it arrives, at least 01:36.540 --> 01:38.990 with very small timing delay. 01:39.570 --> 01:45.730 And there are many examples where the delay function will block you from doing what you want. 01:45.750 --> 01:54.000 For example, let's say you want to make two blinks, OK, here we have one blink, but let's say you 01:54.000 --> 01:57.530 want to make two energy blinks at different rates. 01:58.110 --> 02:04.120 So the first lady, for example, with blink every four hundred milliseconds and the signal that you 02:04.170 --> 02:06.990 will blink every eight seconds. 02:07.390 --> 02:09.480 OK, how can you actually do this? 02:09.480 --> 02:16.590 Because if you blink every eight seconds, it means you have to write a delay of eight seconds and you 02:16.590 --> 02:23.490 have to block the program for eight seconds, which means you are going to be so late when reading the 02:23.490 --> 02:29.330 cell, you might even miss some data, which means also that you can't make the other blink every one 02:29.340 --> 02:30.240 hundred milliseconds. 02:30.720 --> 02:38.280 So the only solution, if you want to keep using delay, is to split the program in many different parts, 02:38.450 --> 02:43.460 OK, with more delays and that will quickly become a huge mess. 02:43.980 --> 02:51.720 And another example, let's say you have one entity that is blinking every two seconds and then you 02:51.720 --> 02:55.040 want to measure some data from a census. 02:55.040 --> 03:00.080 So, for example, you want to measure the distance from an object with another sensor. 03:00.090 --> 03:02.690 That's what we are going to do in the following of these schools. 03:03.180 --> 03:10.020 And if the object is to close from the sensor, you are going to put on another energy to make sure 03:10.020 --> 03:14.070 that the user knows that there is an obstacle in the way. 03:14.430 --> 03:21.690 The thing is that with the energy that blinks and things, well, you would only be able to read the 03:21.690 --> 03:23.340 sensor every two seconds. 03:23.730 --> 03:31.020 So it means you will be late by telling the user that there is an obstacle and that can be a real problem 03:31.020 --> 03:31.870 for your application. 03:32.280 --> 03:34.160 So that's just a few examples. 03:34.620 --> 03:41.520 And if you already have tried to make programs by yourself with more than just one thing in your program, 03:41.820 --> 03:48.410 OK, we have multiple tasks, then you may have seen also that you are quite limiting by using this 03:48.450 --> 03:55.470 delay function, because the thing is that on an hourly no, it's not like a normal computer when you 03:55.470 --> 04:01.180 can have what we call multi training and that you can have multiple actions that run in parallel. 04:01.200 --> 04:02.870 So that would not be a problem here. 04:03.180 --> 04:05.520 You have just one action at the time. 04:05.790 --> 04:09.180 You can only execute one instruction at a time. 04:09.510 --> 04:10.920 So if you block, we delay. 04:11.340 --> 04:13.450 Anything else can't be executed. 04:13.950 --> 04:15.480 So that is the problem. 04:15.810 --> 04:22.830 And the good news is that there is a solution to that using other time functionalities of the idea that 04:22.830 --> 04:24.300 we are going to see right now.