Week 01

The Assignment

- Instructions ————————————————————————

Circuit

Connect two LEDs to your Arduino using a breadboard

Connect one switch to your Arduino using a breadboard

Code

1 Read a momentary switch being pressed

2 When the program starts, both LEDs are off

3 When the switch is pressed once, the first LED turns on

4 When the switch is pressed the second time, the second LED turns on (the first one should also still be on)

5 When the switch is pressed the third time, both LEDs turn off

6 Repeat this same cycle of LEDs turning on and off in sequence (off, one LED, two LEDs, off…)

- Circuit ———————————————————————————

- Code ———————————————————————————–

int led1PIN=9;
int led2PIN=6;
int btnPIN=2;
int count=0;
int btnVal=0;
int pre_btnVal=0;

void setup() {
  pinMode(led1PIN,OUTPUT);
  pinMode(led2PIN,OUTPUT);
  pinMode(btnPIN,INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here:
 btnVal = digitalRead(btnPIN);
  if(btnVal != pre_btnVal){ 
  // when the btn is clicked
\    if (btnVal == HIGH){
\    count++; //count=count+1
\    Serial.print("Count:");
\    Serial.println(count);
\    delay(50);
\    //if push the btn, LED1 is on
\    if (btnVal == HIGH && count==1){
\    digitalWrite(led1PIN, HIGH);
\    digitalWrite(led2PIN, LOW);
\    delay(50);
\    //if you push the btn, LED2 is on (LED1 is still on)
\    } else if (btnVal == HIGH && count==2) {
\    digitalWrite(led1PIN, HIGH);
\    digitalWrite(led2PIN, HIGH);
\    delay(50);
\    //if you push the btn, both LEDs turn off
\    } else if (btnVal == HIGH && count==3) {
\    digitalWrite(led1PIN, LOW);
\    digitalWrite(led2PIN, LOW);
\    delay(50);
\    } 
   }
   if(count > 3){
\    pre_btnVal = 0;
\    btnVal = 0;
\    count = 0;
  // save the previous button state for the next loop 
\    }else{ 
\    pre_btnVal = btnVal;
\    }
\    delay(50);
  }
}

- Thoughts/Reflections ——————————————————————

I struggled with how to light up the LED. There were two options: looping using “count” command, or coding in order based on the LED’s HIGH/LOW information. In the end, I chose the former, referring to the link below.

Digital Input: Falling or Rising Edge : https://learn.newmedia.dog/tutorials/arduino-and-electronics/arduino/digital-io-rising-or-falling-edge/

It is helpful for me and easy to understand how to code. When I was coding and the LED wasn’t working properly (the code didn’t seem to be wrong), that was because the LED wasn’t physically inserted properly. It took me a while to realize that was a simple problem…