WEBVTT 1 00:00:00.160 --> 00:00:02.799 Welcome to the deep Dive, the place where we take 2 00:00:02.799 --> 00:00:06.200 your source material and find the most valuable insights just 3 00:00:06.280 --> 00:00:06.519 for you. 4 00:00:07.080 --> 00:00:10.439 And today we're doing a deep dive into these excerpts 5 00:00:10.599 --> 00:00:14.119 from the The Ardueno Cookbook, third Edition. You've given us 6 00:00:14.160 --> 00:00:15.119 quite a collection. 7 00:00:14.800 --> 00:00:19.440 Here, right, a really good stack chapters appendices, covering well 8 00:00:19.519 --> 00:00:22.679 everything from the real basics like programming in math, all 9 00:00:22.679 --> 00:00:28.079 the way up to networking, sensors, motors, sound displays. 10 00:00:27.760 --> 00:00:30.559 And even the really nitty gritty stuff like low level 11 00:00:30.600 --> 00:00:32.960 hardware details and memory optimization. 12 00:00:33.359 --> 00:00:36.280 It's packed, it really is. Think of this deep dive 13 00:00:36.320 --> 00:00:39.079 as your guide, helping you navigate the practical side of 14 00:00:39.119 --> 00:00:42.159 making things with Arduino. We're pulling out the key ideas, 15 00:00:42.159 --> 00:00:45.719 the surprising details from these sources to get you informed fast. 16 00:00:45.799 --> 00:00:48.320 Yeah, the goal seems to be moving beyond just blinking 17 00:00:48.320 --> 00:00:51.479 an led Right, how do you build something interactive, something connected, 18 00:00:51.560 --> 00:00:52.759 something smarter? 19 00:00:53.039 --> 00:00:56.200 Exactly? So we'll explore the programming building blocks, how your 20 00:00:56.240 --> 00:00:58.560 board talks to things, how you sense the world and 21 00:00:58.600 --> 00:01:01.799 make things happen in it, connect online, manage time, and. 22 00:01:01.840 --> 00:01:03.799 Even peek under the hood at the hardware and how 23 00:01:03.840 --> 00:01:05.159 to make your code run efficiently. 24 00:01:05.200 --> 00:01:08.640 Okay, let's unpack this stack. Where do we start foundation? 25 00:01:09.200 --> 00:01:11.159 I guess programming basics. 26 00:01:11.200 --> 00:01:14.280 It makes sense Chapter two parts of the preface ye, 27 00:01:14.400 --> 00:01:18.319 chapter one. Yeah, they all lay this groundwork. And yeah, 28 00:01:18.680 --> 00:01:21.439 it confirms our dueno programming is based on C and 29 00:01:21.480 --> 00:01:22.319 C plus plus nine. 30 00:01:22.359 --> 00:01:24.760 It feels very practical, not theoretical totally. 31 00:01:25.560 --> 00:01:28.079 The focus is immediately on what you need to do, 32 00:01:28.239 --> 00:01:31.200 like that basic sketch structure you always see set. 33 00:01:31.079 --> 00:01:33.599 Up which runs just once right when you power up 34 00:01:33.599 --> 00:01:34.280 a resea. 35 00:01:34.200 --> 00:01:37.799 Exactly, and then loop which just well, loops runs over 36 00:01:37.840 --> 00:01:38.159 and over. 37 00:01:38.319 --> 00:01:40.920 And the sources also mention serial event. 38 00:01:41.400 --> 00:01:44.719 Ah. Yes, that's a handy one. It's a special function 39 00:01:44.719 --> 00:01:47.519 that runs automatically if there's new serial data waiting. Good 40 00:01:47.519 --> 00:01:51.200 for handling incoming messages without constantly checking in your main loop. 41 00:01:51.319 --> 00:01:53.239 But not on all boards you mentioned. 42 00:01:53.000 --> 00:01:56.599 Right, important caveat boards like the Leonardo anything based on 43 00:01:56.640 --> 00:01:58.280 the Ateen Mega three to two AT four, they don't 44 00:01:58.319 --> 00:02:01.079 support serial event in the same way you'd handle cereal 45 00:02:01.120 --> 00:02:01.719 differently there. 46 00:02:01.920 --> 00:02:06.239 Okay, so inside setup and loop you're dealing with data. 47 00:02:06.319 --> 00:02:10.360 The sources introduce data types like INNT and there's a 48 00:02:10.400 --> 00:02:10.879 catch there. 49 00:02:11.000 --> 00:02:13.360 Yeah, this is a good detail. They highlight and int 50 00:02:13.520 --> 00:02:16.120 isn't always the same size. On an HUNO an eight 51 00:02:16.159 --> 00:02:18.919 bit board it's two bytes okay, But on a thirty 52 00:02:18.919 --> 00:02:21.520 two bit board like a SAMD based one, and int 53 00:02:21.599 --> 00:02:23.639 is usually four bytes ah okay. 54 00:02:23.639 --> 00:02:25.680 That could definitely cause problems if you're not expecting it, 55 00:02:25.759 --> 00:02:28.280 especially sending data between different board types. 56 00:02:28.360 --> 00:02:32.039 Precisely, they point out that unsigned short inint is reliably 57 00:02:32.039 --> 00:02:34.680 two bytes on both, which can be useful if you 58 00:02:34.680 --> 00:02:36.000 need a consistent size. 59 00:02:36.159 --> 00:02:40.039 Good tip and for collections of data arrays. The sources 60 00:02:40.039 --> 00:02:42.240 seem pretty insistent about checking array bounds. 61 00:02:42.280 --> 00:02:45.039 Oh, absolutely critical. It's so easy to write code that 62 00:02:45.199 --> 00:02:48.719 accidentally reads or writes past the end of your array. 63 00:02:48.520 --> 00:02:50.039 And the compiler one always warn you. 64 00:02:50.319 --> 00:02:53.439 Often it won't know, and then your sketch just crashes later, 65 00:02:53.759 --> 00:02:57.599 maybe seemingly randomly. It's super frustrating. Using a constant for 66 00:02:57.639 --> 00:03:00.639 the eray size and checking against it is key makes sense. 67 00:03:00.840 --> 00:03:03.479 Then there's text. The book compares our dueno string objects 68 00:03:03.479 --> 00:03:06.560 with C style character arrays. String seems easier. 69 00:03:06.840 --> 00:03:09.639 It is definitely more convenient for like joining text together, 70 00:03:10.080 --> 00:03:12.599 but there's a trade off, especially on boards with limited 71 00:03:12.680 --> 00:03:13.199 RAM like. 72 00:03:13.120 --> 00:03:14.759 The UNO memory issues. 73 00:03:14.919 --> 00:03:18.680 Yeah, string objects can use more memory both flash and RAM, 74 00:03:18.879 --> 00:03:22.120 and worse, heavy use of string manipulation in a complex 75 00:03:22.159 --> 00:03:24.879 sketch can fragment the RAM over time. 76 00:03:25.080 --> 00:03:26.879 Leading to those mysterious crashes. 77 00:03:26.919 --> 00:03:30.560 Again exactly so Sea style character arrays. While needing more 78 00:03:30.599 --> 00:03:33.240 manual handling, you have to manage the memory yourself, can 79 00:03:33.280 --> 00:03:36.280 be much more memory efficient and predictable. They mentioned the 80 00:03:36.280 --> 00:03:39.719 start talk function as an example for parsing Sea style strings. 81 00:03:40.039 --> 00:03:43.199 Good to know the options structuring code is also important. 82 00:03:43.240 --> 00:03:47.520 Functions defining functions, deciding what they return maybe an end, 83 00:03:47.639 --> 00:03:48.560 maybe nothing, void. 84 00:03:48.840 --> 00:03:50.840 What if you need a function to give back like 85 00:03:50.879 --> 00:03:52.039 two or three values. 86 00:03:52.639 --> 00:03:55.199 The practical way, often shown in examples is to have 87 00:03:55.240 --> 00:03:58.159 the function modify global variables rather than trying to return 88 00:03:58.199 --> 00:04:01.520 a complex structure. Maybe but it works. 89 00:04:01.360 --> 00:04:04.719 Okay, then control flowifles switch. 90 00:04:04.599 --> 00:04:08.199 Standard stuff with switch, Remember it needs numeric constants for 91 00:04:08.199 --> 00:04:10.719 the cases, and you must use brake after each case. 92 00:04:10.960 --> 00:04:13.400 Usually otherwise, execution just falls through. 93 00:04:13.199 --> 00:04:16.439 To the next case, ah, right and loops for for 94 00:04:16.600 --> 00:04:17.519 a while yep. 95 00:04:17.560 --> 00:04:21.040 And then operators lots of operators. Your basic math plus 96 00:04:21.079 --> 00:04:23.160 minus times divide. 97 00:04:22.920 --> 00:04:25.759 Increment decrement plus plus plus type. Though the book notes 98 00:04:25.800 --> 00:04:28.879 result result plus one is just as efficient and maybe clearer. 99 00:04:29.000 --> 00:04:31.600 Yeah, result plus plus is common but no real speed 100 00:04:31.639 --> 00:04:35.000 game readability is often better. Then there's modulus. 101 00:04:34.639 --> 00:04:38.519 Percent for remainders useful for checking even nod or wrapping counter. 102 00:04:38.399 --> 00:04:41.480 Super useful, and comparison operators. Yeah, the big one. 103 00:04:41.519 --> 00:04:43.839 Don't mix up it, please don't please don't get if 104 00:04:44.199 --> 00:04:47.519 value five compares value to five, if value five assigns 105 00:04:47.519 --> 00:04:50.279 five to value, and because five is non zero, the 106 00:04:50.360 --> 00:04:52.279 if condition becomes always true. 107 00:04:52.040 --> 00:04:53.800 A nightmare bug defined totally. 108 00:04:53.879 --> 00:04:56.240 Then logical operators in A and D or candy for 109 00:04:56.279 --> 00:04:57.639 combining conditions. 110 00:04:57.240 --> 00:05:00.199 And bitwise operators for fiddling with individual. 111 00:04:59.759 --> 00:05:03.720 Bits right and and dan. But often the helper functions 112 00:05:03.759 --> 00:05:07.519 are easier bitrid bitright, bitset, bit clear, bit much more readable. 113 00:05:07.639 --> 00:05:11.800 Good point operator precedents use parentheses to be sure. 114 00:05:11.759 --> 00:05:14.959 Always good advice, and the book mentions garbage in garbage out. 115 00:05:15.160 --> 00:05:18.800 Check your inputs even if example, skip it for brevity. Also, 116 00:05:19.199 --> 00:05:21.240 watch out for variable overflow. 117 00:05:21.000 --> 00:05:23.759 Where a calculation result is too big for the variable type. 118 00:05:23.920 --> 00:05:26.680 Yep, the ide might not warn you unless you turn 119 00:05:26.759 --> 00:05:31.040 warnings way up. For constants, const is better than hashtag define. 120 00:05:31.600 --> 00:05:34.600 Why's that? Because const variables have a type so the 121 00:05:34.600 --> 00:05:37.839 compiler can check if you're using them correctly. Hashtag define 122 00:05:37.920 --> 00:05:41.720 is just text replacement basically, Plus the compiler often optimizes 123 00:05:41.759 --> 00:05:43.639 constvarrables away if they aren't needed. 124 00:05:43.759 --> 00:05:47.959 Smart Lastly, on basics, board variations matter. Three point three 125 00:05:48.040 --> 00:05:48.839 V versus. 126 00:05:48.639 --> 00:05:51.480 Five V huge difference, and not just voltage but pin 127 00:05:51.600 --> 00:05:54.680 current limits. An UDO pin might handle forty million amps, 128 00:05:54.839 --> 00:05:56.959 but a thirty two bit board pin might only handle 129 00:05:57.000 --> 00:05:57.720 seven million amps. 130 00:05:57.800 --> 00:05:59.800 So you can't just drive an LED directly from any 131 00:06:00.199 --> 00:06:00.839 on any board. 132 00:06:00.920 --> 00:06:03.160 Nope, you have to check the SVATA sheet and form 133 00:06:03.199 --> 00:06:08.319 factors differ too, UNO MKR, Nano zero effcshield compatibility. Lots 134 00:06:08.319 --> 00:06:09.199 of practical details. 135 00:06:09.279 --> 00:06:12.160 Okay, solid foundation. Now how do these boards actually talk 136 00:06:12.199 --> 00:06:15.240 to things? Cereal I two CSBI right, Chapter four. 137 00:06:15.160 --> 00:06:17.759 And thirteen get into this. Cereal is kind of the workhorse. 138 00:06:18.360 --> 00:06:21.639 Flexible talks to computers other devices. 139 00:06:21.319 --> 00:06:24.480 Usually over that USB connection, which also uploads the sketch. 140 00:06:24.600 --> 00:06:27.959 Yep, you start with serial dot begin setting the BOD right, Yeah, 141 00:06:28.160 --> 00:06:31.519 crucial step both ends must match speed or yeah gibberish 142 00:06:31.720 --> 00:06:35.279 just random characters. Yeah, Then cerreal dot print or serial 143 00:06:35.399 --> 00:06:39.759 dot print to send data. A check serial dot available 144 00:06:39.759 --> 00:06:42.199 to see if data has arrived, then Cereal dot read 145 00:06:42.279 --> 00:06:45.639 to get a byte or serial dot parsit serial dot 146 00:06:45.639 --> 00:06:46.959 parse float for numbers. 147 00:06:47.040 --> 00:06:49.160 You need to decide how to structure the data right 148 00:06:49.319 --> 00:06:51.040 text versus binary exactly. 149 00:06:51.079 --> 00:06:53.879 Text is easier to debug, maybe use commas as dilimiters. 150 00:06:54.240 --> 00:06:56.720 Binary is more compact, but you really need to know 151 00:06:56.759 --> 00:06:59.680 the data types on both ends. Functions like low byte 152 00:06:59.720 --> 00:07:02.120 and i bite help with multibyte values. 153 00:07:02.199 --> 00:07:05.560 The IDEs Serial monitor and serial quatter are useful. 154 00:07:05.199 --> 00:07:09.279 Here absolutely monitor for text, plotter for graphing numbers, visually 155 00:07:09.279 --> 00:07:12.040 great for sensors. And there are other terminal programs too, 156 00:07:12.079 --> 00:07:12.639 like qute com. 157 00:07:12.800 --> 00:07:15.079 What if you need more serial ports than the board has, 158 00:07:15.240 --> 00:07:17.680 like on a MOOO, That's where software Cereal comes in. 159 00:07:17.800 --> 00:07:20.160 It's a library that lets you use other digital pins 160 00:07:20.480 --> 00:07:23.560 to simulate a serial port. Not as fast or reliable 161 00:07:23.560 --> 00:07:27.000 as hardware Cereal, but a life saver. Sometimes boards like 162 00:07:27.040 --> 00:07:30.639 the Mega or newer ARM boards often have multiple hardware 163 00:07:30.639 --> 00:07:31.600 serial ports built in. 164 00:07:31.720 --> 00:07:34.959 Okay, moving from talking to the computer to talking between chips. 165 00:07:35.360 --> 00:07:39.399 I two C integrated circuit great protocol uses just two 166 00:07:39.399 --> 00:07:42.759 wires SDA and SEL plus power and ground. You can 167 00:07:42.800 --> 00:07:44.879 connect multiple devices to those same two wires. 168 00:07:44.879 --> 00:07:45.680 How does that work? 169 00:07:45.759 --> 00:07:49.120 Each device needs a unique address. The arduino acts as 170 00:07:49.160 --> 00:07:51.920 the master and it addresses the specific slave device it 171 00:07:51.959 --> 00:07:54.279 wants to talk to, like maybe a sensor A address 172 00:07:54.360 --> 00:07:55.160 serial by five. 173 00:07:55.000 --> 00:07:57.160 A using the wire library YEP. 174 00:07:57.199 --> 00:08:00.240 Wired up begin transmission, wired dot write, wired up in 175 00:08:00.360 --> 00:08:03.480 transmission to send wired dot request FROUM, and wired dot 176 00:08:03.600 --> 00:08:07.680 read to receive sound straightforward. Any catches voltage levels. If 177 00:08:07.720 --> 00:08:09.439 you have a five VR duino and a three point 178 00:08:09.519 --> 00:08:12.439 three v I two C sensor, you absolutely need a 179 00:08:12.439 --> 00:08:15.279 logic level shifter between them, otherwise you risk frying the sensor. 180 00:08:15.360 --> 00:08:18.439 Ah, good warning. The examples show reading e proms connecting 181 00:08:18.480 --> 00:08:20.000 our duenos, even a we nunchuck. 182 00:08:20.120 --> 00:08:22.480 Yeah, the nunchuck uses it two C for its accelerometer. 183 00:08:22.800 --> 00:08:23.600 Cool example. 184 00:08:23.680 --> 00:08:27.240 Okay, then there's SPI Serial peripheral interface. 185 00:08:26.959 --> 00:08:30.160 Right, often faster than it. Two C uses four main 186 00:08:30.240 --> 00:08:34.440 lines Mosai, MISO, SCK and ss or cs. 187 00:08:34.159 --> 00:08:36.600 Master out, slave in, master and slave out, clock and 188 00:08:36.679 --> 00:08:37.919 slave select exactly. 189 00:08:38.279 --> 00:08:41.080 MOSAI and MESA are separate data lines, which helps the speed. 190 00:08:41.600 --> 00:08:43.000 SCK is the clock signal. 191 00:08:43.159 --> 00:08:45.200 How do multiple SPI devices work? 192 00:08:45.360 --> 00:08:48.960 They share Mosai, MISO and SEK, but each slave device 193 00:08:49.039 --> 00:08:52.720 needs its own dedicated slave select SS or JIP select 194 00:08:52.879 --> 00:08:55.279 cspin controlled by the arduino, So. 195 00:08:55.240 --> 00:08:57.840 The arduena pulls one CS line low to talk to 196 00:08:57.879 --> 00:08:59.600 that specific device precisely. 197 00:08:59.720 --> 00:09:01.840 The example of using an SD card reader and a 198 00:09:01.879 --> 00:09:05.279 TFT display together illustrates this well. Both my use SPI. 199 00:09:05.519 --> 00:09:07.440 They share the main three lines, but you need two 200 00:09:07.559 --> 00:09:10.240 separate Arduino pins for their individual CS lines. 201 00:09:10.320 --> 00:09:12.559 Got it. Okay, we know how to program, how communicate. 202 00:09:12.639 --> 00:09:14.960 Now let's get our hands dirty interacting with the physical 203 00:09:14.960 --> 00:09:16.720 world inputs and outputs. 204 00:09:16.799 --> 00:09:18.679 Yeah, this is where it gets fun. Chapters five through 205 00:09:18.720 --> 00:09:22.159 eleven cover this, starting with inputs digital and analog. 206 00:09:22.519 --> 00:09:25.639 Digital is just high or low voltage right. 207 00:09:26.159 --> 00:09:30.159 Digital read after setting the pin with pin mode pin 208 00:09:30.440 --> 00:09:34.360 I nput and remember the voltage level for HGH differs 209 00:09:34.399 --> 00:09:36.120 between three point three V and five. 210 00:09:36.039 --> 00:09:38.240 V boards, and analog is analog. 211 00:09:38.320 --> 00:09:41.320 Reed reads a voltage on an analog input pin and 212 00:09:41.360 --> 00:09:43.919 converts it to a number, usually zero to kenna to 213 00:09:43.919 --> 00:09:48.159 twenty three. Unos have six analog pins, megas have sixteen. 214 00:09:48.320 --> 00:09:51.440 The book covers common inputs like switches potentiometers. 215 00:09:51.480 --> 00:09:54.840 Potentiometers are great examples of analog input and voltage division. 216 00:09:55.360 --> 00:09:58.960 Also photo resistors light sensors that change resistance. You need 217 00:09:59.000 --> 00:10:01.799 a fixed resistor with to create a voltage divider circuit. 218 00:10:01.919 --> 00:10:04.799 Microphones too, Yeah, electro microphone breakouts. You read them with 219 00:10:04.879 --> 00:10:06.840 an analog read but you need to account for the 220 00:10:06.919 --> 00:10:09.960 DC offset in the signal temperature sensors like the analog 221 00:10:10.039 --> 00:10:13.080 TMP thirty six or the digital DS eighteen B twenty 222 00:10:13.080 --> 00:10:16.240 which uses a different protocol called one wire and GPS modules, 223 00:10:16.279 --> 00:10:19.320 those usually communicate over cereal sending streams of text data. 224 00:10:19.399 --> 00:10:23.360 Libraries like tiny GPS plus make parsing that data much easier. 225 00:10:23.399 --> 00:10:26.279 What about needing more analog inputs than the board has 226 00:10:26.720 --> 00:10:27.639 clever trick. 227 00:10:28.000 --> 00:10:30.879 Use a multiplexer chip like the forty five to one 228 00:10:31.039 --> 00:10:34.759 unless you switch one analog pin between multiple inputs. The 229 00:10:34.759 --> 00:10:38.240 book also shows measuring higher voltages using a voltage divider 230 00:10:38.240 --> 00:10:41.320 circuit and calculating the actual voltage and reading IR remote 231 00:10:41.360 --> 00:10:43.519 controls using the I Remote library. 232 00:10:43.240 --> 00:10:46.159 Cool now outputs making things happen. 233 00:10:46.600 --> 00:10:50.000 LED's first the classic, but watch that pin current limit 234 00:10:50.039 --> 00:10:53.559 we mentioned forty mari on Uno, maybe only seven marry 235 00:10:53.600 --> 00:10:57.279 out another's for bright LEDs or lots of immunia transistor 236 00:10:57.360 --> 00:10:59.320 or moss fat to handle the current. 237 00:10:59.440 --> 00:11:03.200 What about those fancy addressable LEDs NeoPixels very popular? 238 00:11:03.320 --> 00:11:05.559 Use a library like a to fruit NeoPixel. You tell 239 00:11:05.559 --> 00:11:07.639 each pixel what color it should be, then call the 240 00:11:07.679 --> 00:11:09.600 show function to update the whole strip at once. 241 00:11:09.639 --> 00:11:12.559 They mention things like color HSV and gamma thirty two. 242 00:11:12.639 --> 00:11:15.559 Yeah, color HSV gives you HU saturation value control, which 243 00:11:15.600 --> 00:11:18.600 could be more intuitive than RGB sometimes, and gamma thirty 244 00:11:18.639 --> 00:11:20.919 two corrects the brightness so colors look more natural to 245 00:11:20.960 --> 00:11:24.679 our eyes. Big consideration power Lots of new epixels need 246 00:11:24.720 --> 00:11:25.960 a separate BF power supply. 247 00:11:26.159 --> 00:11:29.840 Okay, what about LED matrices? Lots of simple LEDs. 248 00:11:29.799 --> 00:11:33.039 Use techniques like multiplexing or Charlie plexing to control many 249 00:11:33.159 --> 00:11:36.679 LEDs with fewer pins. The book explains the concepts and wiring. 250 00:11:36.799 --> 00:11:40.159 It can get complex, especially animating Charlie plex displays and 251 00:11:40.240 --> 00:11:42.360 multiplexing can draw a surprising amount of power. 252 00:11:42.399 --> 00:11:45.200 Sometimes seven segment displays for numbers. 253 00:11:45.000 --> 00:11:49.159 Yep again often multiplexed. Understanding common cathode versus common and 254 00:11:49.279 --> 00:11:52.000 ode is key, but using an I two C driver 255 00:11:52.159 --> 00:11:55.039 chip like the HT sixteen K thirty three makes it 256 00:11:55.120 --> 00:11:55.720 much simpler. 257 00:11:55.799 --> 00:11:59.480 Just two wires plus power moving Beyond simple lights, displays 258 00:11:59.559 --> 00:12:00.799 like LCA. 259 00:12:00.480 --> 00:12:04.279 Text LCDs are common. Use the Liquid Crystal library, print text, 260 00:12:04.399 --> 00:12:07.600 set the curser position scroll. You can even create custom characters. 261 00:12:07.639 --> 00:12:10.799 What about graphical displays olds color LCDs. 262 00:12:10.879 --> 00:12:13.159 They offer much more detail, but yet more complex wiring. 263 00:12:13.279 --> 00:12:16.039 Usually monochrome O leads often use I two C or 264 00:12:16.120 --> 00:12:19.679 SPI libraries like Adafruit SSD one three zero six are common. 265 00:12:20.080 --> 00:12:23.240 Color LCDs typically use SPI like the ST seven seven 266 00:12:23.360 --> 00:12:26.159 seven three five or ST seven seven eight nine. Types. Again, 267 00:12:26.200 --> 00:12:27.600 with dedicated libraries, is. 268 00:12:27.519 --> 00:12:29.519 It hard to switch between display types? 269 00:12:29.960 --> 00:12:32.759 Sometimes not. Adafruit, for instance, tries to keep their graphics 270 00:12:32.799 --> 00:12:35.399 library APIs similar, which helps. The main trade off is 271 00:12:35.440 --> 00:12:40.320 often monochrome versus color, cost, memory usage, power draw okay. 272 00:12:40.159 --> 00:12:42.159 Visual output covered. Let's make things move. 273 00:12:42.559 --> 00:12:46.159 Servos easiest way to get precise rotational movement. Use the 274 00:12:46.200 --> 00:12:48.960 Serbo library attached to a pin tell at an angle 275 00:12:48.960 --> 00:12:49.960 with Servo dot write. 276 00:12:50.159 --> 00:12:53.159 Simple scoops are easy, but there was a timer conflict warning. 277 00:12:53.399 --> 00:12:57.279 Uh yes, good catch on the un The servil library 278 00:12:57.360 --> 00:13:00.519 uses Timer one. Dot analog rite on pins No. Ten 279 00:13:00.720 --> 00:13:03.840 also uses Timer one, so you can't use servos NPWM 280 00:13:03.879 --> 00:13:06.799 on those specific bins at the same time hardware limitation. 281 00:13:07.000 --> 00:13:10.279 Good to know DC motors like in Little Robots. 282 00:13:10.000 --> 00:13:12.799 Right, They need more power than an Ardueno pin can supply, 283 00:13:13.120 --> 00:13:15.720 and you usually want to control direction too, so you 284 00:13:15.799 --> 00:13:19.200 need external drivers transistors for simple on off or h 285 00:13:19.279 --> 00:13:21.240 bridges like the L two ninety three or L two 286 00:13:21.279 --> 00:13:24.720 ninety eight for speed and direction control using PWM motor 287 00:13:24.759 --> 00:13:26.039 shields bundle this up neatly. 288 00:13:26.159 --> 00:13:29.120 The book shows controlling motors based on sensors, yeah, like. 289 00:13:29.120 --> 00:13:31.720 Using photo resistors to make a simple light following robot. 290 00:13:31.879 --> 00:13:35.799 Classic project stepper motors for more precise positioning. 291 00:13:36.679 --> 00:13:40.440 Often driven using dedicated driver boards like the Easy Driver 292 00:13:40.600 --> 00:13:44.039 for bipolar steppers. The duino tills the driver the direction 293 00:13:44.159 --> 00:13:46.840 and when to step, and the driver handles the tricky 294 00:13:46.879 --> 00:13:50.559 coil energizing sequences. You might not even need the standard 295 00:13:50.600 --> 00:13:52.000 stepper library with that approach. 296 00:13:52.320 --> 00:13:53.759 Interesting. What about sound? 297 00:13:54.440 --> 00:13:58.159 Simplest way is the tone function. Connect a speaker or 298 00:13:58.159 --> 00:14:01.120 piezo buzzer to a digital pin, give it a frequency 299 00:14:01.120 --> 00:14:02.519 in duration beep. 300 00:14:02.679 --> 00:14:03.759 Can you play melodies? 301 00:14:03.799 --> 00:14:06.519 Sure? Store the note frequencies and durations in a raise, 302 00:14:06.879 --> 00:14:09.720 then loop through them using tone. The book even shows 303 00:14:09.759 --> 00:14:12.440 generating tones with more precise microsecond timing. 304 00:14:12.720 --> 00:14:14.440 MIDI output two YEP. 305 00:14:14.320 --> 00:14:17.480 Sending many messages out the serial TX pin. Just remember 306 00:14:17.519 --> 00:14:20.480 to disconnect anything connected to pin one TX when you 307 00:14:20.519 --> 00:14:22.679 upload a new sketch, otherwise the uproad. 308 00:14:22.440 --> 00:14:25.360 Might fail and complex sounds the odd winosketch. 309 00:14:25.440 --> 00:14:28.799 Ah yeah, that's a NEAT one, a software synthesizer using 310 00:14:28.799 --> 00:14:32.240 potentiometers for control, but the sources mentioned is likely only 311 00:14:32.279 --> 00:14:34.960 for eight bit boards like the UNO. A good reminder 312 00:14:34.960 --> 00:14:37.399 that some low level code isn't easily portable. 313 00:14:37.559 --> 00:14:40.799 So much interaction, but timing is crucial for. 314 00:14:40.840 --> 00:14:44.639 Orchestrating all this absolutely to chapter twelve and eighteen, focus 315 00:14:44.639 --> 00:14:49.240 on time. The basic pause is delay stops everything for milliseconds, 316 00:14:49.440 --> 00:14:51.799 delay microseconds for shorter pauses. 317 00:14:51.840 --> 00:14:52.919 There's also a pulse. 318 00:14:52.759 --> 00:14:56.480 Ent yeah, for measuring how long a digital pulse. Lasts useful, 319 00:14:56.600 --> 00:14:59.039 but it has limitations on the range and accuracy of 320 00:14:59.080 --> 00:15:00.440 pulses that can bear reliably. 321 00:15:00.559 --> 00:15:03.480 But delay stops everything, right, that's often bad. 322 00:15:03.720 --> 00:15:07.000 It often is. That's why the milli's function is so important. 323 00:15:07.120 --> 00:15:09.600 It returns the number of milliseconds since the board started. 324 00:15:10.080 --> 00:15:11.919 Use it for non blocking timing, like. 325 00:15:11.840 --> 00:15:13.240 The blink without delay example. 326 00:15:13.440 --> 00:15:16.399 Exactly check the current millise, compare it to when the 327 00:15:16.440 --> 00:15:18.919 last action happened, and if enough time has passed, do 328 00:15:19.000 --> 00:15:21.759 the action again and record the new time. This lets 329 00:15:21.799 --> 00:15:26.440 your loop keep running quickly, checking sensors, handlink communication, and 330 00:15:26.519 --> 00:15:28.879 blinking the LED seemingly all at once. 331 00:15:29.080 --> 00:15:31.600 Much better. What about scheduling tasks for later? 332 00:15:31.960 --> 00:15:34.159 The time and time alarms libraries are great for that. 333 00:15:34.519 --> 00:15:37.840 You can set alarms to trigger functions once time once 334 00:15:38.159 --> 00:15:41.080 or repeatedly time repeat any catches. You must call alarm 335 00:15:41.159 --> 00:15:44.440 dot delay frequently in your loop. That's the function that 336 00:15:44.480 --> 00:15:46.679 actually checks if any alarms are due. If you don't 337 00:15:46.679 --> 00:15:48.759 call it, your alarms won't fire, and there's usually a 338 00:15:48.799 --> 00:15:50.639 limit to how many alarms you can have active, like 339 00:15:50.679 --> 00:15:52.399 six on AVR boards by default. 340 00:15:52.440 --> 00:15:56.080 Okay. The book also mentions hardware timers under the hood. 341 00:15:56.240 --> 00:15:59.399 Yeah, the micro controller ship itself has dedicated hardware timers. Yeah. 342 00:16:00.039 --> 00:16:03.200 On the UNO's eighty Mega three twenty eight timers zero 343 00:16:03.320 --> 00:16:07.159 is used by Millie's delay and PWM on pins five 344 00:16:07.159 --> 00:16:10.559 to six. Timer one is for PWM on pins nine 345 00:16:10.600 --> 00:16:13.960 to ten, and the SERVERO Library Tier II is PWM 346 00:16:14.000 --> 00:16:15.200 on pins three eleven. 347 00:16:15.440 --> 00:16:18.399 Ah, So that's the hardware reason for the servo PWM 348 00:16:18.399 --> 00:16:21.200 conflict on pins nine to ten. They both need timer 349 00:16:21.240 --> 00:16:22.039 one exactly. 350 00:16:22.679 --> 00:16:25.639 Knowing this helps diagnose weird issues. You can even manipulate 351 00:16:25.639 --> 00:16:29.039 the timer registers directly for super precise PWM or timing, 352 00:16:29.279 --> 00:16:30.320 but that's getting advanced. 353 00:16:30.360 --> 00:16:32.879 There was also something about faster analog reads. 354 00:16:33.120 --> 00:16:36.159 Right, you can change the ADC analog to digital converter 355 00:16:36.279 --> 00:16:38.799 clock speed standard and allogreed takes about one hundred and 356 00:16:38.840 --> 00:16:41.320 ten microseconds. By tweaking a register, you can get it 357 00:16:41.360 --> 00:16:44.320 down to maybe seventeen microseconds on a sixteen megawords board. 358 00:16:44.440 --> 00:16:47.559 Wow, that's a huge speed up, useful for audio, perfect for. 359 00:16:47.519 --> 00:16:51.360 Things like audio sampling or capturing other fast changing signals. 360 00:16:51.399 --> 00:16:53.159 And the Watchdog timer for sleep YEP. 361 00:16:53.600 --> 00:16:56.440 It's mainly designed to reset the board if the code hangs, 362 00:16:56.879 --> 00:16:58.440 but you can also use it to put the board 363 00:16:58.440 --> 00:17:01.320 into a low power sleep for sure fixed periods fifteen 364 00:17:01.360 --> 00:17:04.920 milliseconds up to eight seconds. You can loop these sleeps 365 00:17:04.920 --> 00:17:06.599 for longer low power delays. 366 00:17:06.920 --> 00:17:12.279 Okay, we've got code communication IO timing. Yeah, what about 367 00:17:12.279 --> 00:17:15.920 connecting to the big wide world? Wi Fi and Ethernet? 368 00:17:16.079 --> 00:17:20.319 Chapter fifteen territory opens up huge possibilities. Ethernet is wired 369 00:17:20.400 --> 00:17:23.039 Wi Fi is wireless need specific hardware, of. 370 00:17:23.039 --> 00:17:26.039 Course, like an Ethernet shield or boards with built in 371 00:17:26.079 --> 00:17:27.240 Wi Fi exactly. 372 00:17:27.400 --> 00:17:30.519 Libraries like Ethernet or waifena handle the low level stuff. 373 00:17:30.720 --> 00:17:33.720 The super cheap espaight to sixty six modules are also mentioned, 374 00:17:33.720 --> 00:17:36.640 amazing value for adding Wi Fi, though maybe a bit 375 00:17:36.640 --> 00:17:38.920 more fiddly to get started with programming them initially. 376 00:17:39.279 --> 00:17:41.759 So Ardno can be a client or a server on 377 00:17:41.799 --> 00:17:44.079 the network. What does being a client involve? 378 00:17:44.200 --> 00:17:48.519 Initiating connections? Sending simple UDP messages for example, or very 379 00:17:48.559 --> 00:17:51.160 commonly acting like a web client, making requests to web 380 00:17:51.200 --> 00:17:51.680 servers to. 381 00:17:51.599 --> 00:17:54.920 Get data like fetching weather data or stock prices. 382 00:17:54.759 --> 00:17:57.880 Or the example in the book getting the current location 383 00:17:57.960 --> 00:18:00.519 of the International Space Station from the open Notify API. 384 00:18:01.240 --> 00:18:04.440 The key is making the request and then parsing the response. 385 00:18:04.079 --> 00:18:06.960 You get back extracting the actual numbers or texts you 386 00:18:07.000 --> 00:18:09.160 need from the HTML or JSON right. 387 00:18:09.400 --> 00:18:13.440 The book shows examples for strings, floats, iNTS. It also 388 00:18:13.480 --> 00:18:18.000 covers requesting XML data, sending data using HTTP post like 389 00:18:18.039 --> 00:18:21.359 filling out a web form, and getting the time using NTP, 390 00:18:21.640 --> 00:18:25.000 even sending tweets YEP, usually via a proxy service like 391 00:18:25.039 --> 00:18:28.839 think speak that handles the authentication and for IoT stuff, 392 00:18:28.960 --> 00:18:29.839 MQTT is. 393 00:18:29.880 --> 00:18:32.319 Key message queuing telemetry transport. 394 00:18:32.519 --> 00:18:36.079 That's the one. Using a library like pubsubclient, your Arduino 395 00:18:36.119 --> 00:18:38.839 can publish data like sensor readings to a central broker 396 00:18:39.279 --> 00:18:41.759 or subscribe to topics to receive commands or data from 397 00:18:41.799 --> 00:18:44.000 other devices. Very efficient for IoT. 398 00:18:44.240 --> 00:18:46.079 Okay, what about acting as a server. 399 00:18:46.000 --> 00:18:49.359 That means your Dueno listens for incoming connections. Most common 400 00:18:49.400 --> 00:18:52.119 is setting it up as a web server using the relevant. 401 00:18:51.759 --> 00:18:54.119