WEBVTT 00:00.180 --> 00:06.590 This is the solution of the previous activity where you need to get some samples from the sensorial, 00:06.600 --> 00:13.380 photoresistor Senzo, and then compute the average of all the values that you got over a certain period 00:13.380 --> 00:13.950 of time. 00:14.230 --> 00:20.070 OK, so we have chosen one hundred samples and fifty milliseconds, which means that the total will 00:20.070 --> 00:21.370 be five seconds. 00:21.600 --> 00:25.840 So let's start and again, let's do that step by step. 00:25.860 --> 00:32.820 So the first thing we are going to do is actually to read from the sensor and using the time functionality 00:32.820 --> 00:35.840 to be able to read every 50 milliseconds. 00:35.850 --> 00:46.010 So let's initialize we define to register then, which is always a zero here. 00:46.740 --> 00:48.540 I'm going to add unsigned. 00:49.850 --> 00:52.910 Long last time. 00:53.880 --> 00:55.950 Let's say right, luminosity. 00:57.930 --> 01:04.890 Which is initialise to Moelis zero, that's the same for the beginning of the program and signed long, 01:05.640 --> 01:15.230 let's say, luminosity, sunchoke, delay and this wedding 20 to 50 milliseconds. 01:15.570 --> 01:15.880 Great. 01:15.900 --> 01:17.040 So now, Inglenook. 01:19.340 --> 01:24.240 So I don't need to initialize the pin again, this is an analog input pin in the loop. 01:24.260 --> 01:31.640 What I am going to do is assign a long time now is equal to Moelis. 01:32.480 --> 01:33.020 Right. 01:33.020 --> 01:40.280 And then so this should be quite easy for, you know, with all the practice that we got, if the time 01:40.280 --> 01:42.830 NUPE minus the last time we have. 01:42.830 --> 01:43.090 Right. 01:43.100 --> 01:49.190 The luminosity is greater than the simple dillehay we enter this. 01:49.190 --> 01:50.660 If we do. 01:50.660 --> 01:55.590 Last time we read the luminosity, we add the delay. 01:57.020 --> 02:06.080 So the next time we enter this, if will be 50 milliseconds after that and then we can read we've analog. 02:06.260 --> 02:15.630 So read the new front sensor and we are going to read that value and put this inside an array. 02:15.950 --> 02:22.580 So that's step two here is we're going to create the right to store the different samples because we 02:22.580 --> 02:25.230 just don't want to read the value and do something with it. 02:25.580 --> 02:31.100 We want to be able to store a few values to here one hundred values over time. 02:31.550 --> 02:33.250 So I'm going to create an array. 02:33.800 --> 02:35.030 It's created here. 02:36.590 --> 02:39.270 So an array of integer value. 02:39.290 --> 02:44.650 OK, because we are only going to get values between zero and one thousand twenty three. 02:45.620 --> 02:47.390 Let's say liminality simple. 02:49.590 --> 02:58.500 Impulsiveness, look, I could name it luminosities sample list, luminosities sample array, also, 02:58.500 --> 03:06.540 what you can do is simply add an S, make sure that when you name your array as easy to understand that 03:06.540 --> 03:11.740 this is a list or at least it's plural and the size of it will be one hundred. 03:11.760 --> 03:14.600 But again, I'm not going to have to code one hundred. 03:14.610 --> 03:19.050 I'm going to create define here, let's say luminosity. 03:21.880 --> 03:22.540 Sample. 03:24.250 --> 03:34.420 Sighs One hundred, this is here and then I'm going to initialize all of the values in Detroit to zero, 03:34.630 --> 03:40.340 and to do that, you can simply use Gary Braces and one zero. 03:40.780 --> 03:43.320 You don't need to repeat the zero hundred time, OK? 03:43.330 --> 03:49.520 If you just do that it with initialize all the values to zero, which is very practical and very efficient. 03:49.660 --> 03:49.870 So. 03:49.960 --> 03:55.340 Right, our luminosity sample contained one hundred samples which are all equal to zero. 03:55.360 --> 04:01.030 So what you need to do now is actually to put each value we rate inside this. 04:01.190 --> 04:01.530 All right. 04:01.840 --> 04:06.150 And of course we need to create a counter int. 04:07.270 --> 04:16.570 That's the index can't start at zero because first we are going to use the index zero and an index one, 04:16.570 --> 04:21.670 two, three, etc., until we reach ninety nine, which is the last index. 04:21.920 --> 04:25.880 And after that we are going to compute the average and go back to zero again. 04:26.230 --> 04:29.710 So let's start with an index come to initialised to zero. 04:30.160 --> 04:35.040 So what we do know we are going to put the value we raise from the sensor to the array. 04:35.050 --> 04:36.130 So luminosity. 04:38.360 --> 04:42.260 Samples with the index counter. 04:44.870 --> 04:51.260 So this will be equal to analog grade from the photoresistor bin. 04:53.170 --> 05:00.930 All right, and then what we do is simply index conter plus plus so we start at zero. 05:00.940 --> 05:06.970 We put the first value, we read in the index zero, then we wait 15 milliseconds. 05:06.970 --> 05:07.780 We come back here. 05:08.050 --> 05:09.800 So now the index is one. 05:10.120 --> 05:13.090 So we put the value one, two, three, etc.. 05:13.900 --> 05:22.810 And now what we need to do is, of course, to check for the end of the story, because once the content 05:22.900 --> 05:26.070 reaches ninety nine, we have the last value. 05:26.260 --> 05:32.410 And when the countdown reaches one hundred and we get here, we don't want to do luminosities samples 05:32.410 --> 05:35.180 with one hundred because this is outside of the array. 05:36.010 --> 05:41.920 So what we are going to do now is before we do this, we are going to check the end condition. 05:42.580 --> 05:50.290 So if index counter is equal to luminosity sample size. 05:51.840 --> 05:59.550 So once we have reached one hundred in this case, what we can do is simply reset the counter. 06:02.250 --> 06:05.260 So index counter is zero, which means that the next. 06:05.280 --> 06:12.120 So just after this, we are going to start again to feel the error rate from zero and then one, two, 06:12.120 --> 06:13.050 three, etc.. 06:13.620 --> 06:19.730 And then, of course, at this point, the rate is filled from zero to ninety nine for all the indexes. 06:19.740 --> 06:22.720 We have some values that we can analyze. 06:22.980 --> 06:29.400 So what we are going to do now is to compute and print average. 06:31.380 --> 06:34.610 We just compute in the average and then we start again. 06:34.620 --> 06:41.490 And so we replace all the previous values one by one theory until we reach one hundred and then we compute 06:41.490 --> 06:44.700 and print the average again, etc., etc.. 06:44.850 --> 06:53.850 So to do this, I am going to create a new function here that see into compute. 06:55.210 --> 06:57.730 Average luminosity. 07:00.410 --> 07:07.100 OK, so it's because I'm going to return the average as an int, but you could use double if you want 07:07.100 --> 07:10.440 more precision, but it is quite good for what we want here. 07:10.880 --> 07:15.200 So I'm going to go through all the values of the orange. 07:15.200 --> 07:22.460 So classic if it is zero and then I lower than the size of the array. 07:22.940 --> 07:24.780 Strachey lower I plus. 07:30.250 --> 07:38.440 And what I'm going to do is so I'm going to create a viable sun, which actually I'm going to put as 07:38.440 --> 07:44.420 a long because into the max value of it is thirty two thousand something. 07:44.960 --> 07:50.320 So here, because we have a lot of values, well, it's quite probable that if we add all the values 07:50.320 --> 07:54.330 together, we are going to go beyond the maximum of the. 07:54.550 --> 07:56.230 So I'm going to use long for the. 07:56.980 --> 08:04.650 And what I'm going to simply sum plus of course initially the sum to zero sum plus equals. 08:04.660 --> 08:06.190 So we add to the sum. 08:08.840 --> 08:17.000 The sample that we have in the three, just so we go through all the values in the area and we just 08:17.000 --> 08:19.690 added them to the same mission to zero. 08:19.710 --> 08:24.340 So at the end, this will contain the sum of all the samples in the area. 08:25.010 --> 08:32.540 And then we simply do return some divided by the luminosity sample size. 08:33.980 --> 08:35.420 Which here is one hundred. 08:35.900 --> 08:44.030 So we add all the elements and then we divide the sum by one hundred, which gives us the average of 08:44.030 --> 08:45.080 all the values. 08:46.060 --> 08:53.380 And this is also written as an e-book, because now the average will be between zero and one thousand 08:53.380 --> 08:53.980 twenty three. 08:54.220 --> 08:55.690 All right, so we're dysfunctional. 08:55.750 --> 08:57.640 We get them right now. 08:57.640 --> 09:03.100 What I'm going to do is create another function, print, average luminosity. 09:05.960 --> 09:11.360 I create another function so I can make a nice prenatal care with lots of details and then I'm going 09:11.360 --> 09:13.340 to call that function Freundel. 09:14.390 --> 09:16.520 So here, let's get so let's do it. 09:16.550 --> 09:20.390 Other age is equal to compute average luminosity. 09:22.230 --> 09:27.740 So I called dysfunction inside dysfunction, and then I will call dysfunction inside the loop. 09:29.650 --> 09:36.940 So what I didn't do, Sam, so if you sell in the setup where you just sit up here, I need to do that. 09:38.400 --> 09:39.060 Biggin. 09:42.070 --> 09:44.230 OK, that's all we need, Indesit. 09:45.490 --> 09:50.530 And now I'm going to do that, so let's do something nice print. 09:52.250 --> 09:54.290 Of the range luminosity. 09:57.730 --> 10:01.200 MySpace and then on the same line, say I, the print. 10:02.450 --> 10:03.900 That's but the number of simple. 10:06.910 --> 10:13.150 And then let's say that print samples based here. 10:15.610 --> 10:16.870 They can avory. 10:19.450 --> 10:24.550 And this childhood friend, the luminosities sample delay. 10:26.740 --> 10:29.330 OK, so not great. 10:30.590 --> 10:35.750 Not a single print with nearly Saigon's. 10:37.730 --> 10:44.940 And finally, you say on that print and then we the average it. 10:46.720 --> 10:51.110 So this way, we just don't train the average, we print some information. 10:51.130 --> 10:51.350 OK. 10:51.370 --> 10:58.080 That gives us more useful information actually, because when we see the average on the same, we will 10:58.090 --> 11:03.160 see the average luminosity for one hundred samples taken every 50 milliseconds. 11:03.160 --> 11:09.990 Is that when we finally find this value on this value, the behavior of the problem will change. 11:10.000 --> 11:13.630 And also this will give us more useful information. 11:14.020 --> 11:14.370 All right. 11:14.380 --> 11:22.780 So now that I have this function and going to call it right here, print other and remove all of that. 11:23.990 --> 11:34.160 So when we have reached the maximum index plus one of the array, which is the precise reason, reset 11:34.370 --> 11:41.990 the counter to continue to rate values and we also print the average luminosity by computing the average 11:41.990 --> 11:43.120 here and then printing. 11:43.130 --> 11:44.880 Nice message for the user. 11:45.950 --> 11:53.210 Just one thing I'm going to add is after we increase the control and we read some value, I'm just going 11:53.210 --> 11:56.060 to add that print. 11:56.150 --> 12:01.700 I'm just going to add a dot so we can kind of see a progression line. 12:01.740 --> 12:07.670 OK, because if I don't add anything, we will not have any output and maybe you don't know what is 12:07.670 --> 12:08.120 happening. 12:08.150 --> 12:12.530 OK, so here, every time we see a dot, we know that we have. 12:12.530 --> 12:12.830 Right. 12:12.830 --> 12:16.170 And added a new value inside this sample array. 12:16.370 --> 12:22.700 And because I use print here, what I'm going to do also is when a computer and print the average, 12:22.700 --> 12:25.310 I'm going to use the print and then. 12:26.560 --> 12:30.130 Just an empty print, Alan, but just to make sure that I go back to a new life. 12:30.160 --> 12:33.940 OK, so we better understand this when I actually run to code. 12:34.270 --> 12:35.800 So it seems good. 12:36.310 --> 12:43.720 Let's first just compile it as activity 20 to see if we have any computation error. 12:44.890 --> 12:46.980 This seems to be good. 12:46.990 --> 12:57.910 So now I am going to upload the code and open the monitor so you can see we have a progression by here. 12:58.360 --> 12:58.960 Quite nice. 12:59.890 --> 13:05.230 And then OK, we have some message, average luminosity for one hundred samples. 13:05.690 --> 13:11.950 I'm going to stop this so they can every 15 minutes we have 341 here. 13:11.950 --> 13:17.080 We have three hundred twenty nine k you can see the average, we get every fight. 13:17.710 --> 13:24.420 Now let's say you put my hand on top of the senseor and you can see the average will be lower. 13:25.000 --> 13:26.840 We have average of sixty five. 13:27.610 --> 13:28.180 All right. 13:29.990 --> 13:36.170 So now you have an efficient way, so this actually this code is kind of a template that you can use 13:36.410 --> 13:39.150 to measure the average of any sense. 13:39.150 --> 13:46.010 So you have to keep this code close to you because you are probably going to need it in the future, 13:46.340 --> 13:51.790 whether it's a photoresistor sensor or a distance sensor, any kind of sensor. 13:52.370 --> 13:54.760 And that is the end of this activity. 13:55.010 --> 13:59.510 And that's also the end of the section on the photoresistor sensor.