Programming with Functions (Procedures)

A neater and more professional way of programming is to use Functions (also known as Procedures).
We can think of a function as a type of mini program within a larger program.
The use of Functions eliminates the need to write endless reams of step by step code which often can repeat itself if the desired function is required more than once.

In this example, I have set up three banks of three LED’s (Green, Red and Yellow) on a breadboard as shown in Fig 2.
The program in Fig 1 shows how to use functions to sequence the LED’s.
See if you can build it and get your program to work using functions.
You can then experiment with using functions – perhaps try some input switches…..

Fig 1

void setup() {  // put your setup code here, to run once:
pinMode(2, OUTPUT);pinMode(3, OUTPUT);pinMode(4, OUTPUT);pinMode(5, OUTPUT);pinMode(6, OUTPUT);pinMode(7, OUTPUT);pinMode(8, OUTPUT);pinMode(9, OUTPUT);pinMode(10, OUTPUT);}
void loop() {  // put your main code here, to run repeatedly:
Green();Red();Yellow();Green(), Red(), Yellow();AllOff();}
void Green(){   digitalWrite(2, HIGH); //turn the LED on  digitalWrite(3, HIGH); //turn the LED on  digitalWrite(4, HIGH); //turn the LED on  delay(250); //wait }
void Red(){  digitalWrite(5, HIGH); //turn the LED on  digitalWrite(6, HIGH); //turn the LED on  digitalWrite(7, HIGH); //turn the LED on  delay(250); //wait }
void Yellow(){  digitalWrite(8, HIGH); //turn the LED on  digitalWrite(9, HIGH); //turn the LED on  digitalWrite(10, HIGH); //turn the LED on  delay(250); //wait }
void AllOff(){  digitalWrite(2, LOW); //Turn LED off by making output LOW  digitalWrite(3, LOW); //Turn LED off by making output LOW  digitalWrite(4, LOW); //Turn LED off by making output LOW  digitalWrite(5, LOW); //Turn LED off by making output LOW  digitalWrite(6, LOW); //Turn LED off by making output LOW  digitalWrite(7, LOW); //Turn LED off by making output LOW  digitalWrite(8, LOW); //Turn LED off by making output LOW  digitalWrite(9, LOW); //Turn LED off by making output LOW  digitalWrite(10, LOW); //Turn LED off by making output LOW  delay(250); //wait }

← Set the mode of your inputs and Outputs as you would in a normal program

← This part calls each of the desired ‘Functions’ in sequence. You will notice that on one line I have called three functions at once separated by comma’s.
This is the actual program sequence.

← Using the ‘Void’ command allows you to define each function (ensure that you use brackets after each function name) – You can define as many functions as you wish, but remember to name them all differently.
In this program I have used four functions called:

Void Green()Void Red()Void Yellow()Void AllOff()

Fig 2

ArduinoFunction1.mp4

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