Arduino Tutorial 4: Understanding Arduino Variables

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/ paulmcwhorter
In this video we learn that you should always use variables when programming instead of constants. This allows you to easily modify complicated programs. We start by writing a program the wrong way, and then show the good way using variables.
You can get the following Elegoo kit, to follow these lessons and play along at home
amzn.to/3c9SJrO
You can get more details about this lesson on our WEB site HERE:
toptechboy.com/arduino-tutori...
[Disclosure of Material Connection: I am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. This means if you visit the link and purchase the item, I will receive an affiliate commission. Regardless, I only recommend products or services I use personally and believe will add value to my readers.]
#Arduino

[@graemefraser9518]

Used hot coffee. Everything went wrong. Won't be making that mistake again

[@HarpreetSingh-yo9ir]

😂😂😂😂😂

[@FernandoRodriguez-uo2fk]

And boooooooom, your tongue melted.

[@yashodhanghule8810]

Nice one 😂😂😂😂

[@fptechreviews6394]

School boy error, ice coffee mate

[@fswarrior9510]

Best comment ever

[@avishekdey1943]

I absolutely love the fact that he makes mistakes on purpose to show us how to fix them. What a king!

[@HaseebAdnan0]

Meanwhile electroboom:

[@bottacap1]

Man finding your channel is like finding the holy grail. Just so you guys know, Paul's got Raspberry Pi videos, and all sorts of other topics for later. Thank you sir, schools would be better if all teachers were like you

[@jakeklic]

I just found his channel and its so great!

[@davidlee9924]

my teachers don’t even teach they just make us watch youtube and learn that way while they sit on their phones

[@roberthead127]

YEAH wish my Teachers where like Paul

[@minipop1138]

I would have got into this hobby much earlier if I had a teacher like you. Well done!

[@sansaningidanbayero6500]

I AGREE 99%. THANK YOU PAUL!

[@RikMeloen]

Tip: at 16:39 where he is changing all the numbers, you can just do Crtl+F and change everything at once.

[@Tryant69]

Very nice tip! thnx

[@jobsanjose1188]

thaaaaaaaaaaaank you so much

[@stuhastie1719]

Hehe, awesome. If you happen to minimise that function, and if you Ctrl+F again, it hides from you till you drag it off the bottom again

[@l.halawani]

@@stuhastie1719 this comment deserves more likes

[@jayjaythezeybork9853]

Thank you!

[@gramofonomanek]

His patience and way how he is explaining is great.Plenty teachers lost that gift.You want to listen,old school.

[@skateguroo7600]

I'm eleven years old and I'm in the academy of S.T.E.A.M I've been needing to learn some new advanced coding and with your channel it makes learning so easy thank you so much keep doing what your doing

[@paulmcwhorter]

Welcome aboard!

[@jameshalpin1274]

Same with me but I have to learn it for a school program

[@intelchip_x86]

cool what game are you programming?

[@harukills]

@@paulmcwhorter haha, boards

[@kmm2-whjyt2secondsago.10]

same with me im 12 but im just learning arduino for fun, this guy is so easy to listen to.

[@Randy2747]

For people starting his course just a bit of advice.... After each lesson I print out the script on paper and write noted down on it. Install in a folder that way I won't forget and if I do I can go back to see what Mr. McWhorter has taught me 😉👍

[@WarenaiSai]

I'm a mechanical eng. grad student just getting into Arduino. Thank you for your dedication to making these great videos Mr. McWhorter!

[@locutussmith]

Sir as an elderly student (69 years of age) may I wholeheartedly thank you for your clear and precise teaching, many thanks from the UK.

[@xxxalphaeverythingxxx8489]

Nice

[@andrewd4906]

Many thanks for making an easy to follow series on the arduino. Managed the homework. Thanks to your explanation the bits of the puzzle are starting to fall into place.

[@niggaz4life635]

best teacher i've ever got

[@Omar_Cubing]

me too

[@normanchristopherson5434]

Wow, Paul! Great instruction. I purchased an Arduino over a year ago and now that I came upon your instruction I dug it out and have started following along. Excellent instruction. You are so easy to follow and very well structured, nice and sequential.

[@senrinakamura4456]

I know how hard is teaching, so I don't criticize my school's teachers. However, every teacher should learn how Paul teaches. You're amazing.

[@Richardj410]

Got my kit and I'm moving along. Thanks for all your hard work and it is helping me.

[@grafophone]

Thank you sir for all tutorials. You are among rare persons to have the ability to teach so well and able to put yourself in place of the person who knows nothing about the matter and tell exactly what he needs immediately for beginning rather than getting lost or throw everything away. Thank you so much.

[@Ewecnt]

After 30 years as an electrical technician I have a solid understanding of the components but your tutorials are still interesting and enjoyable to watch. I’m new to the Arduino platform but not entirely new to programming even though I have never worked in C++. So for me your videos are an extremely good way to absorb these new skills at my own pace. In fact what ever level someone is at you allow them to go at their own pace. Good work! Keep it up. And thank you.

[@danthemancasey]

Excellent example of one use for variables! Thank you for another great video!

[@tegolley]

True

[@evolutionsfake]

I must say I am an old fart considering that I am a husband and a father, and I was pleasantly surprised to easily see the transition not just to memorize code, but finally understand why people use variables, and greatly appreciate you purposely giving us a hard time because you know we'd want to learn from it. This is the most pleasant video I have ever followed along with and I can feel myself getting smarter with these videos. I'm not just watching him I'm programming and putting stuff together. Thank you!

[@star_labs_official]

i think the old fart part is true, thats it

[@gogokom6634]

You're the best, I graduated from college last year and know most of the things you explain , but I enjoy and learn a lot from you.I like the way you teach 💪

[@awkward_bomb]

Wow this lecture just like on a fundamental level really was impressive. I have more experience with computer science than I do with micro controllers, and your presentation of basic principles like variable types, self referencing variable names, and the importance of camel case and case sensitivity by actually demonstrating common pitfalls is great for someone who is completely new.

[@cboyles]

Appreciate these lessons so much and can’t describe the joy it brings me to be able to figure out how to do the homework assignments! The Elegoo “Most Complete Starter Kit Mega 2560 Project” was a 62nd birthday gift last year. Using my university summer break to learn something completely foreign to me. It is amazingly fun to be able to make a light blink! Thank you Paul McWhorter!

[@mikehenry9672]

Damn I did the same thing and bought the same exact kit for my summer break from college. I’m going for electrical technician

[@Omar_Cubing]

this is the best Arduino tutorial series in the world MR Paul, your are an AMAZING! person

[@burnermaster5375]

Thank you Paul. You are an excellent teacher. I'm so glad that I found you. I've been thinking about ideas using Arduino for years and I finally pulled the trigger. An early Christmas present to myself if you will. I'm hooked. I varied from your lesson with the code you taught and having 3 LEDS flashing random patterns next to me is so satisfying. Thank you.

[@giorat2352]

One of my friends, suggested me this channel and after a few days of watching your videos I have to say that you are an incredible teacher! Good job sir!

[@lucast3006]

I’ve seen other channels go through Arduino basics and yours is the best by far! Having a lot of fun learning this.

[@paulmcwhorter]

Glad you enjoy it!

[@GeoGebweiler]

Paul, You are the best ! It makes so much fun to learn all about the Arduino with Your tutorial. Thumbs up !

[@josephjackson1567]

I have a lot of experience with PLC programming and decided to get into arduino for building small projects and a hobby. im mighty impressed by the versatility of it and the ease of the syntax. keep up the good work and continue drinking your coffee.

[@zaidelkacak888]

I have been following over 30+ of your Arduino classes now during the quarantine, relearning a lot of stuff I forgot, so on this day I would like to say THANK YOU and wish you a HAPPY TEACHERS DAY!

[@amicaaggarwal]

Thank you so much! This is really helping me to understand Arduino!

[@jassimjaved3309]

Very nice tutorials ! Thank you so much for making these! One feature my friend told me is that if we want to replace any word which is being repeated many times we can select that word and press ctr+f then we can replace that word anywhere it appears. Just a very nice tip I've learned. Keep up the amazing content!

[@imho2278]

Yes, saves me from typing everything as a word doc and then using find!!!

[@sourabhp5840]

I really needed a teacher like you who does topics slow and completely !! Thanks a lot sir

[@yp4577]

I'm only on lesson 4 but I have to say I am amazed at your ability to clearly explain an (for me) otherwise obscure subject. I took an arduino course close to where I live and didn't really understand much of it afterwards, but thanks to your videos it's a lot clearer to me. Keep up the good work

[@edgargraadtvanroggen7384]

Wonderful!!! Very clear! Love the sound effects: BOOM!

[@billlaird7332]

Outstanding series. Ordered my Arduino starter kit. Will be here tomorrow. A couple of constructive criticisms. 1. SOS was informally initially recognized as meaning "Save Our Ship". As it became more wildly used as a universal distress signal on land, sea, and air it was reinterpreted as "Save Our Souls". An extension of this idea is when aircraft pilots file a flight plan with the FAA, one of the items in the flight plan is the "Number of Souls on Board."" As a HAM, or licensed Amateur Radio Operator, I want to offer the correct timing spacing in Morse code for dots, dashes, and spacing. 1. The length of a dot is one time unit. 2. The length of a dash is three time units. 3. The length between symbols (dots and dashes) of the same letter is 1 time unit. 4. The length between letters is 3 time units. 5. The length between words is 7 time units. The length of the time unit varies with the speed of transmission. The time unit for a transmission speed of 5 words per minute is 4 times the length of the time unit for a transmission speed of 20 words a minute.

[@derricks2366]

I was able to finish another homework assignment with ease, thanks to your easy to understand lessons. I think you will be the first person i support on patreon.

[@Vyktor992]

Thank you so much for these lectures, you're making learning so enjoyable, you are a gift for all students that give you their attention

[@spencerg7967]

You are the man! Just started tonight and this is awesome! Thanks for the great videos! Somebody might have said this before, but to help out with the spacing of flashes in Morse there are a few rules. Dits are 1 unit. Dahs are 3 units. The "off time" or space between dits and dahs is 1 unit. The space between letters/characters is 3 units. The space between words is 7 units. For a repeated code of S.O.S you would just pick a unit of time and use the Morse Code rules. Make sure to make the last "Low" delay 7 units of whatever time you are using to make the space between repeated words of S.O.S. I put my "int"s below for R, W, and B LEDs as well as the time intervals for dits, dahs, and spaces as an example. Hope this helps! int R=13; int W=12; int B=8; int dit=250; int dah=750; int spacedd=250; int spacechar=750; int spaceword=1750;

[@dbower58]

I should have read the comments before I came up with the same exact thing 😀 73 de W2GT

[@DaedalusYoung]

Even better if you declare a variable for just the unit, and build the other variables on that. If you want to change the unit length, you now have to change every single one, where otherwise, you only need to change the one. Something like this: int unit = 250; int pulseShort = unit * 1; int pulseLong = unit * 3; int spacedd = unit * 1; int spacechar = unit * 3; int spaceword = unit * 7;

[@2006death2006]

learning step by step this way is one of the best i have with your codeing help so far made a police car led light flashing with leds blue and red i will share my code here might not be the best but i only been doing this for 30 mins int RedLed=13; int BlueLed=12; int flash=50; int timeoff=2000; void setup() { // put your setup code here, to run once: pinMode(13,OUTPUT); pinMode(12,OUTPUT); } void loop() { // put your main code here, to run repeatedly: digitalWrite(RedLed,HIGH); delay(flash); digitalWrite(RedLed,LOW); delay(flash); digitalWrite(BlueLed,HIGH); delay(flash); digitalWrite(BlueLed,LOW); delay(flash); digitalWrite(RedLed,HIGH); delay(flash); digitalWrite(RedLed,LOW); delay(flash); digitalWrite(BlueLed,HIGH); delay(flash); digitalWrite(BlueLed,LOW); delay(flash); digitalWrite(RedLed,HIGH); delay(flash); digitalWrite(RedLed,LOW); delay(flash); digitalWrite(BlueLed,HIGH); delay(flash); digitalWrite(BlueLed,LOW); delay(flash); delay(timeoff); }

[@Omar_Cubing]

great ,keep going

[@gabrielceolato2]

Im a programmer and now going into arduino, checkout how to do ``C ++ FOR LOOP`` so your code will be much more cleaner

[@imho2278]

Is that with the same wiring setup?

[@tonyflow6244]

in case anyone reads Vapor Wave's response and wonders how to implement the for loop I'll leave a sample here // LED pin numbers int redPin = 8; int bluePin = 6; int greenPin = 4; // delay times(ms) int longDelay = 500; int medDelay = 300; int shortDelay = 100; void setup() { // put your setup code here, to run once: pinMode(redPin,OUTPUT); pinMode(bluePin,OUTPUT); pinMode(greenPin,OUTPUT); } void loop() { // put your main code here, to run repeatedly: // loop red 3 times with longDelay for(int i = 0; i < 3; i++) { digitalWrite(redPin,HIGH); delay(longDelay); digitalWrite(redPin,LOW); delay(longDelay); } // loop blue 5 times with medDelay for(int i = 0; i < 5; i++) { digitalWrite(bluePin,HIGH); delay(medDelay); digitalWrite(bluePin,LOW); delay(medDelay); } // loop green 8 times with shortDelay for(int i = 0; i < 8; i++) { digitalWrite(greenPin,HIGH); delay(shortDelay); digitalWrite(greenPin,LOW); delay(shortDelay); } }

[@hughvanzyl549]

Hi Paul. I am now 62 and sooo excited to find your youtube videos. Just bought the kit yesterday. You are a fantastic teacher. Thankyou for your videos. Soo amazing. I will be building everything as i go along. Know programming from mainframe years but this is so awesome. Awesome gift to a youngster just playing games. Get so frustrated with people that dont learn how to do things. Keep up the awesome job. God bless you for doing this for us. Blessed day. Cape Town South Africa.

[@colepdx187]

I ordered my super starter kit from Amazon today, using your link. I paid a little extra to have it delivered today because I have the patience of a software engineer. :)

[@MrMoose233]

14:42 Tip to save some time: You can also use ctrl+f to find and replace all instances of the number with the variable. Then you can just scan your code to ensure the replacements were all correct and then run your code

[@antonalderliesten1421]

so in the variable definitions at the top i highlight the "dah" for an example and then press cntrl F and then it highlights all the "dahs" and then what? i see they are all highlighted but a search bar comes up and cant seem to change them to my new variable definition...am i missing something?

[@joeb.fromsydneyaustralia5313]

No more Ice Coffee for me Paul... I do these after work in Sydney - Coffee keeping me up. Hope you'll allow me to stay in the class... I'm doing really well.

[@tothydroponics6733]

I'm a former teacher and I just have to tell you man that I love your style brother! Great Job! You assume the student knows nothing and that they should learn EVERYTHING!

[@paulmcwhorter]

Awesome! Thank you!

[@GDub1958]

Paul, just back here again reviewing the basics AGAIN, YES THIS MAKES SENSE! Thanks, Gary

[@Ro0vEdits]

Thank you for teaching us how to make the SOS signal... You never know when you’ll need it... 😂😂😂

[@gymratt88]

after you change it, i'm going to change my mind again.. perfect life lesson. welcome to the real world.

[@JR-je7ce]

I know im abit late on this video but after 3 weeks of trying to wrap my head around arduino and getting no where I was about ready give and im so glad I found your series before giving up. You good sir are an amazing teacher thank you so much

[@mi.Dalton]

My Arduino is still in the mail, and this course is so easy to follow along and learn concepts that I’m able to still learn without having it in front of me. Some of the clearest instruction i can find on the internet!

[@kevinonorato7223]

gREAT sTUFF pAUL. tHANKS. wATCH THAT cAPS lOCK.

[@amynoacid]

I love your method of teaching. You do it in the way any new user can understand and you make it look like the "errors" you make are unintentional.

[@doomplanetone]

Hello Paul, I'm a lucky person because I found your tutorials. Uptill now I understand it, previous i was in the fog. Thank you and your team for making them, cheers

[@ExcelHumor112]

Yup, I got the program to work again. Thanks for your clear instructions! They made it really easy to make the program work.

[@The_Adm_Jachov]

I just purchased an Arduino for my Ender 3 firmware upgrade which was successful but never done any kind of programming before. But started watching these tutorials and this guy is amazing, easy to follow his instructions and i'm actually starting to enjoy basic Arduino programming. Wish i had a tutor like him when i was at school (then again, we only just got rid of the stone tablets by the time i left haha) Thank you Paul, you're a godsend for Arduino for dummies :) Merry Christmas to you and to everyone else out there, stay safe and be well.

[@jaws2858]

I’m 58 years old, this is my first time working with programming and I need to tell you this is the best class I’ve ever had! Thank you! I’m stoked.

[@eleftheriasalpighidis6826]

And I thought I finished school at 17, oh, it's so good to be back at school. Your a legend Paul. Back at school at the age of 59. Never to old to learn. Thanking You gratefully.

[@paulmcwhorter]

Legend!

[@oldcrazyeye6482]

So glad I found this tutorial. I'm 36 and completely new to this. So far I configured a rasberry as my desktop with the sole purpose of programing my arduino. Loving the way you teach 👍👍👍

[@robertrosario3030]

You explain much more clearly and entertaining than my professor. Please keep teaching those who want to learn :D.

[@ALIENMACHINES]

What a great teacher!, I mean he doesnt talk a million miles an hour, explains and explains some more and really gets you interested, I never thought Arduino could be so much fun!

[@davidmajersky1969]

Hi Paul, I did the assignment and it works great this is a lot of fun, can't wait for the next lesson.

[@smash7777-]

Another awesome tutorial for me to get tore in about! I am a complete beginner so these lessons are exactly what I need. I can't believe these is so much fun to be had with this wee gadget! 😁

[@BrentIngroumtv]

Hey Paul! Your videos are great and very helpful for a beginning Arduinist like myself. These are the most helpful, straight forward Arduino instruction videos I have seen so far. I am fluent in other programming languages, so I was able to answer all the questions that you were asking the audience. I hope you heard me. Anyway, I was watching this video and kept asking myself if it's possible to create functions in Arduino (I looked it up, and sure enough you can). This might be a helpful topic to cover for the sake of others and would go along the same lines of this video here. Thanks so much for these videos!

[@andrewclayton1886]

Paul you're an amazing teacher! Looking forward to finishing all these tutorials!

[@sunnydayhobbies]

Another great lesson! I cannot wait to get my starter kit this Christmas! Thanks, Paul!

[@arthurfricchione8119]

Thanks Paul. Learning the terminology is probably the most interesting to me. Guess the more times you write it the easier it will be. My kit showed up yesterday so I’m on my way. Thanks for sharing your videos and your knowledge Artie 😊 like your format of building in stages. 😊

[@llewsub]

I watch a lot of tutorials across many different subjects, this guy is one of the best (so far). So happy to see his content has continued. Super excited to learn with you. YOU RULE, PAUL!!!

[@NeilNSD]

Loved this tutorial! It really helped me a lot!

[@richterxxazula]

Loved the way the lectures are presented! I will definitely watch all the remaining tutorials. Thank you Mr. McWhorter.

[@paulmcwhorter]

You are welcome!

[@pavz]

This is a great tutorial. I'm completely new to the Arduino or any programming at all and I found this tutorial being a great introduction. My Arduino is arriving tomorrow... Can't wait.

[@erygion]

Great lesson Mr. Mcwhorter :) I'm excited to see what is to come!

[@gregs1262]

Hi Paul, I think you are a great teacher and I am learning heaps - God bless you.

[@patrickmachacek894]

I`m always excited for the next lesson and I`m really looking forward to the more complicated stuff in videos 20 and beyond! You really are a great teacher. I`m even considering to learn Python now!

[@paulmcwhorter]

Great to hear!

[@michaelburak1484]

I have messed with Arduino before but decided to start from scratch using your Great video's! Thank you very much!

[@omarinhomoudy]

I have started today to learn Arduino and I am really enjoying to watch your tutorials.. Ahh Hakuna Matata

[@collectorsinfo]

Just what i needed & is really helping. Would be real nice to have some video's on some viewers projects & requests on items they are trying to make, but cant quite make it work & you step in to help & suggest a better alternative. Fault finding is a great teacher. Depending on costs, i would happily pay for this & hope myself & others would appreciate even more lesson. Loving it so far. Keep it up.

[@harleyfatboyuk]

just started my Arduino journey and this is immensely interesting and helpful thank you

[@lorenzoandfriends1193]

You're such a great teacher. You master this language but you pretend to not notice the cause of the error. This gives us time to think on solving the problem. Great technique indeed.

[@souljr.]

Again with another absolute banger of a lesson! I never would have thought to do Morse Code experiments with an LED! Lots of fun, and loved learning how to declare and use variables! Massive time saver for changing the parameters of the whole program. Using what I learned through the last lesson and reading comments talking about how better to optimize the program, I was able to get the homework for this lesson to run with only 53 lines of code!! There was some referring back to my notes I've been taking, but I did it mostly off of memory!

[@vedikashinde4312]

ur teaching is really good! i m gonna continue this whole series for sure!

[@redwhiteblue5041]

Excellent course. I never knew anyone who liked or knew anything about programming or robotics. You make this look very doable.

[@melomaniac4202]

I HV NO WORDS FOR HIM HE IS SUCH A GOOD AND SLOWLY TEACHING TEACHER THANK YOU

[@tedcook8749]

Thanks again Paul! This homework project really shows us there is still lots of basics to learn, but great way to enforce what we learned. Now if I could only figure out why green and blue leds are dimmer than the red.... Its nearly 40 years since I did any programming- this is awesome. Patreon for sure!

[@tedcook8749]

I had forgotten to set pinmodes for green and blue

[@Kelvin555s]

These tutorials are the best I have seen in here. So easy to get on. Thanks a lot.

[@MrSikkandar]

everyday i see one video and i amazed to see the way you teach things, in the end of the video the topic is crystal clear

[@micr0chap]

Variables brilliantly explained simply. Thanks, Paul. I learned plenty from your practical and detailed demo.

[@paulmcwhorter]

Glad it was helpful!

[@qaundaledingglethenintenth1955]

Thank you so much I could never understand an Arduino until I saw your videos you are the best person I've know to teach me about Arduino

[@elisabethoze3227]

i really like the way you teaching, easy to understand. thank you so much

[@nikkyrachit]

Completed the task as instructed in the first go. The way you explained it makes things easier. Thanks a lot

[@cimetovsan]

Mr McWhorter, thank you so much so this valuable lessons. Your teaching methodology, and principles are so well organized and really cover a wide aspect of learning electronics with programming. With this lessons i feel like going back to school :) blessing

[@EricTheMadMan]

Great job Paul!! I really appreciate your teaching skills 👍😁 and I am enjoying the series so far. Thanks.

[@hasan-motam]

Thanks for another great video Paul. Had a lot of fun completing this homework. Looking forward to the next lesson.

[@carycolon3847]

Started watching at lesson 1. I’m hooked. Very interesting and fun Can’t stop watching!!

[@carpenter123154]

Enjoyed this tutorial! I especially like the way you follow a natural progression of what replicates (and would be) my Trial and Error period--and then you demonstrate how to avoid those errors in future programming. Seriously cool approach to teaching.

[@paulmcwhorter]

In these lessons for the most part I do not deliberately make mistakes, but admit I am not uber-careful as I code, as when mistakes happen you can see how I think through them. Troubleshooting and debugging are two of the most important skills you can have as an engineer, and in life in general.

[@richardstewart4135]

As a ham radio operator, I got a bit of a chuckle out of this particular lesson. I had kept my homework lesson from the previous lesson in place through this one, and it made this one rather easy. Looking forward to the next lesson.

[@ProlificPianist]

Already took a programming class learning Golang and some C++ a few years back but this is definitely a great refresher for most all of the syntax and such that I lost. Just a tad bit slow for me since I already know it, but I'd imagine that this would be perfection for beginner programmers. Good work sir!

[@LordAndyvaile]

i got the starter kit and after watching this video i actually wrote a program and using a red a yellow and red led made a set of working traffic lights in correct sequence lol , great videos mate very clear and concise

[@SusiesRepeat]

Just now learning about Arduino, your series is helping me immensely, thanks very much.

[@dopportunitychannel1294]

This is the best arduino tutorial there is. Thanks Paul. Youre the best Arduino Teacher.....

[@kemrajnaidoo9878]

very help full . love watching your tutorials

[@Vanessa-ws1kb]

i was putting this off for so long because i wasn't sure if it was my thing! thank goodness i finally pushed myself to start this! i legit can;t stop now! i'm binge-watching arduino tutorials!

[@aaronhammock2099]

Great series. Coding finally makes since. Thanks to you and Arduino