How to Control Servo Motors with an Arduino!

welcome to Master Tech this is a potentiometer this is a Servo and in today's video we're going to learn to control one of these with one of these using an Arduino microcontroller [Music] so this tutorial does stand completely on its own but if you'd like to follow along with all the Arduino tutorials we've done on the channel I'll leave a link to the playlist in the description of the video a card to it somewhere at the top of the window now and the kit we're using in these initial few projects is the official Arduino starter kit I got it from Amazon I'll put a link to that in the description section of the video as well if you want to follow along exactly for this project I'm assuming you already have your programming software and your Arduino and breadboard ready to go this is our first project controlling an analog output in this case a variable position Servo motor for this project in addition to your Arduino and a breadboard you'll need some jumper wires two 100 microfarad capacitors a potentiometer and a three wire Servo motor as well as header pins if your Servo has a female connection Port like mine before we dive into the circuit build I'm going to tell you a little bit about what capacitors do in circuits and you know what that means so maybe you're familiar with or you've heard the fact that a car burns more gas per distance traveled on Startup than it does while operating at steady state speed electrical motors have a very similar phenomenon when they start moving they draw more current and that can cause fluctuations in voltage in your circuit that can damage electrical components or just cause them to not work properly and precisely we need the electrical equivalent of your car's gas tank and here's where the capacitor comes in capacitor is basically composed of two sheets of conductive metal very often aluminum separated by a thin dielectric insulating layer typically like ceramic it essentially stores up a small amount of charge like a mini battery and can be used to smooth out changes in voltage in your circuit it charges and discharges quite a bit faster than a battery it stores less total energy and its mode of electrical potential storage is actually an electric field rather than chemical storage like a normal battery the most common and probably best metaphor for how a capacitor serves your circuit is the metaphor of a dam that's Dam YouTube please don't flag my content in this scenario you have water AKA electricity flowing in at a somewhat unreliable rate but averaging enough to power the circuit the capacitor acts as a dam or intermediate storage tank where a small electric Reservoir can be stored and then a smooth steady and reliable flow of electricity comes out from the other side even if the supply decreases for a little like when you have a large startup current draw from a motor and that's it for this all right so the Arduino folks call this project mood Q in the Arduino beginner project manual because they suggest using the potentiometer to point your Servo to some text that says what kind of mood you're currently in it's not a bad idea but I think I found a more fun way to use the project be sure to watch till the end to see how I use it now let's go ahead and jump into the physical circuit build first and then we'll check out the code let me know in the comments below if you like circuit build before code or think it should be the other way around so as always connect your 5 volt power and ground pins to the power rails on one side of your breadboard and now let's look at the potentiometer piece of the circuit jumper 5 volts to one pin of the potentiometer and ground to the other and then hook up one of our 100 microfarad capacitors across the same pins make sure if you have a polarized capacitor and it has a stripe down one side you hook that side to ground a capacitor hooked up in Reverse can explode and I do not recommend trying that now go ahead and run a long jumper wire from analog input pin a0 to the Arduino board now when we rotate the potentiometer we'll be changing the voltage transmit to our analog pin between 0 and 5 volts and that's it for the potentiometer Loop so now let's check out our Servo control Loop if you have female connector ports on the servo like this pop in header pins so that you can plug the servo into your breadboard then on the red wire hook up 5 volts the black wire hook up ground and just like the potentiometer Loop add a decoupling AKA smoothing capacitor across these pins careful to get the ground strip on the proper side the white wire gets hooked up to an output pin that has pulse width modulation or pwm capabilities essentially pulse width modulation allows you to use a discrete or digital on off signal to control an analog or variable State device by flickering the power on and off in pulses way faster than you can detect with the naked eye pwm pins on your Arduino board are indicated with a little squiggly line and I'll be using pin 9 but any pwm pin is fine and that's it for the physical build the servo has a few little attachments that can go on it so feel free to pick your favorite now let's check our program or sketch for the project start by importing the servo control module by typing pound sign include then inside angle brackets type servo.h it's important to note include commands don't get a semicolon at the end like a typical line of Arduino code then we're going to Define our Servo by typing Servo and then the name of our Servo I'll just call mine my Servo Now define a few variables we'll use throughout the project first we'll create a constant to store a potentiometer's pin identification which is a0 next Define an integer we'll use to store the potentiometer value and an integer we'll use to store our angle command in the setup piece of the program which will run once at system startup tell the code what pin the servo will use by the command myservo dot attach and then the pin number which again for me is 9. then type the command serial dot begin followed by our baud rate or bits per second of data transfer which is going to be 9600 and that's it for the setup code now let's check out the loop code which runs repeatedly the whole time our Arduino is powered up so we basically want to read the voltage coming in from our potentiometer and command the servo to an equivalent position based on that to do this start by using the command analog read on the pot pin and store it in our pot Val variable then type up a few serial dot print lines one for the text pot value and the second for the actual pot value reading this will let us monitor the potentiometer's readings once we power up the circuit and make sure we're seeing change as we turn it now to convert that pot Val to a usable angle we're going to use the command app and map takes a total of five arguments we're gonna store the result of map in our angle variable and give map the arguments of raw value which is pot Val and then the raw Min and Max which are 0 and 1 0 2 3 then our scaled Min and Max which are 0 and 179. now add two more serial print commands to display the angle similar to the pot valve and make sure your final serial dot print command is a Serial dot println command so that every Loop that runs will start on a new line now the final thing to do in the code is just the command myservo dot right and then write the angle command to the actual Servo then just add a delay of 10 to 15 milliseconds so the servo actually has a chance to move where it's commanded and that's the whole project go ahead and verify it then upload it and let's take a look at what we get you should now have a Servo arm that moves with your potentiometer and has a full 180 degree range of motion this is already super fun and the first time I got this working I was really just sitting here messing with this thing forever now again the project manual suggested you attach like a cardboard craft labeled with a few moods to point to the mood that you're in that's a fun idea but I found this to be way more fun [Music] and so that is going to be as far as we build out this awesome project today if you have any questions about anything you saw here today be sure to let me know about them in the comments below this video and I will get back to you as soon as I can if you guys want to help me do bigger and more complex projects in the future consider becoming a Super supporter of the channel at my patreon link in the description of this video as well shout out to Dale my first patreon supporter making this all possible also hit the like button subscribe to the channel ring that little notification button hit any other buttons you can find until next time good luck with your projects and thanks for watching [Music]