• . As I used ESP32, the first step was to know its pins configuration
• . Open the downloaded arduino IDE where the codes will be developed
• . Initialize the output pin: Next, you need to initialize the output pin that will be used to control the LED. This involves setting the direction of the pin as an output pin using the pinMode function.
• . Write a value to the output pin: Once the output pin is initialized, you can write a value to it using the digitalWrite function to turn the LED on or off
• . Writing a HIGH value to the output pin will turn the LED on, while writing a LOW value will turn it off
• . Add a delay: Depending on the requirements of your application, you may want to add a delay after writing the value to the output pin to ensure that the LED remains on or off for a certain amount of time. This can be done using the delay function, which will pause the program for a specified amount of time.
• . Repeat the process: Finally, the above steps can be repeated in a loop or other iterative process, allowing the LED to be turned on and off in a repeating pattern.

 
                                                            
                                                               int led=18;
                                                               void setup()
                                                               {
                                                                 pinMode(led, OUTPUT);
                                                               }
                                                               void loop()
                                                               {
                                                                 digitalWrite(led, HIGH);
                                                                 delay(2000);
                                                                 digitalWrite(led, LOW);
                                                                 delay(500);
                                                                 }
                                                            
                                                           

Hardware implementation

Afeter programming in arduino IDE, you verify by compiling your code, if there are errors you debug them.If no error, you connect your microcontroller board to your computer through its dedicated USB and upload the codes in its memory.Then after, connect a LED via a protective resistor to limit the current that can destroy a LED to the chosen pin of esp32 here is pin18 as it is the one I chose and declared in my codes.

Image above shows hardware implementation of a Blinking a LED using the ESP32 microcontroller

• 1. Set up the hardware: Connect the ESP32 board to the traffic light controller circuit, which consists of LEDs and resistors. The LEDs have been used to simulate the traffic lights, and the resistors used to limit the current flowing through them.
• 2. Create a new sketch: Open a new sketch in the IDE.
• 3. Define the pin assignments: Define the pin numbers of the ESP32 that are connected to the traffic light controller circuit.
• 4. Set the pin modes: Set the pin modes to OUTPUT so that the ESP32 can control the LEDs
• 5. Define the traffic light states: Define the different states of the traffic lights as green, yellow, and red and the delay() function to set the duration of each state.
• 6. Write the main program: Write the main program to control the traffic lights
• 7. Test the program: Upload the program to the ESP32 and test it with the traffic light controller circuit. Check that the traffic lights are changing according to the programmed sequence.

 
                                                               
                                                               int green=21;
                                                               int orange=19;
                                                               int red=18;
                                                               void setup(){
                                                               pinMode(green, OUTPUT);
                                                               pinMode(orange, OUTPUT);
                                                               pinMode(red, OUTPUT);

                                                               }
                                                               void loop(){
                                                               digitalWrite(green, HIGH);
                                                               delay(2000);
                                                               digitalWrite(green, LOW);
                                                               digitalWrite(orange, HIGH);
                                                               delay(1000);
                                                               digitalWrite(orange, LOW);
                                                               digitalWrite(red, HIGH);
                                                               delay(6000);
                                                               digitalWrite(red, LOW);
                                                               }
                                                               
                                                               

Below video uploaded on youtube is of traffic light using ESP32.

The above works were about programming the outputs devices.

Programming input devices

Programming input devices in a microcontroller is important because it enables the microcontroller to receive and respond to input signals from various devices such as sensors, switches, and buttons. The input signals can provide valuable information about the state of the external environment or user interaction, which can be used to control the behavior of the microcontroller and perform various tasks.
They are many reasons why programming input devices in a microcontroller is important such as:
Sensing and measurement: Many microcontroller-based systems use sensors to measure physical parameters such as temperature, pressure, and light intensity. The microcontroller can read the sensor data and use it to control other parts of the system, such as turning on a fan to cool down a device if the temperature is too high.
User interaction: Microcontrollers are often used in devices that require user input, such as remote controls, game controllers, and keypads. The microcontroller can read the user input and perform the appropriate action, such as changing the channel on a TV or moving a character in a game.
Automation and control: Microcontrollers are widely used in industrial and automation systems to control various processes and machines. Inputs from sensors and switches can be used to monitor the state of the system and adjust the control parameters accordingly.
Security and safety: Input devices can also be used for security and safety purposes. For example, a microcontroller-based security system can use inputs from sensors and switches to detect intrusion or fire and trigger an alarm or activate a sprinkler system.
In summary, programming input devices in a microcontroller is essential for enabling the microcontroller to interact with the external environment, perform various tasks, and ensure the safety and security of the system.

Steps for Programming a push button using EsP32 to control a LED:

• Connect the push button and LED to the ESP32 board: Connect one pin of the push button to a digital pin of the ESP32 and the other pin to the ground pin of the ESP32.
• Connect one pin of the LED to another digital pin of the ESP32 and the other pin to a resistor and then to the ground pin of the ESP32.
• Create a new sketch: Open a new sketch in the IDE and give it a suitable name.
• Define the pin assignments: Define the pin numbers of the ESP32 that are connected to the push button and LED.
• Set the pin modes: Set the pin modes to INPUT_PULLUP for the push button and OUTPUT for the LED.
• Write the main program: Write the main program to read the state of the push button using the digitalRead() function. If the button is pressed, turn on the LED using the digitalWrite() function. If the button is not pressed, turn off the LED.

 
                                                               
                                                                  
                                                                  
 
                                                                     
                                                                  int led = 19;
                                                                  int button = 18;
                                                                  int button_bit;
                                                                  void setup() {
                                                                  Serial.begin(9600);
                                                                  pinMode(led,OUTPUT);
                                                                  pinMode(button,INPUT);
  
                                                                  }

                                                                  void loop() {
                                                                   button_bit=digitalRead(button); 
                                                                   Serial.print(button_bit);
                                                                   delay(100);
                                                                   if(button_bit ==1)
                                                                   {
                                                                  digitalWrite(led, HIGH);
                                                                   }
                                                                   else
                                                                   {
                                                                  digitalWrite(led, LOW);
                                                                   }
                                                                   }
                                                                     
                                                                    
                                                               
                                                              

Image below shows hardware implementation of a push button to control a LED using EsP32 microcontroller

Above video is of controlling a LED trough push button using ESP32 uploaded on youtube.

Control of LEDS Via Bluetooth by using EsP32

Steps:

• 1. Set up the hardware: Connect the LEDs to the appropriate pins(here I used pin 19 and GND) on the ESP32 board. Connect a Bluetooth module to the ESP32 board(here for esp32 Bluetooth is embedded).
• 2. Initialize the Bluetooth module: Use the BluetoothSerial library to initialize the Bluetooth module and set the device name and PIN code for pairing.
• 3. Initialize the LEDs: Use the pinMode() function to set the LED pins as outputs in the setup() function(here is pin 19).
• 4. Set up the loop() function: Use the Serial.available() function to check for incoming data from the Bluetooth module. If data is available, read it and convert it to an integer value using the Serial.parseInt() function.
• 5. Control the LEDs: Use the digitalWrite() function to set the LED pins HIGH or LOW based on the incoming integer value.
• 6. Upload the code: Compile and upload the code to the ESP32 board using the Arduino IDE.
• 7. Download a serial Bluetooth terminal app on smartphone
• 8. Pair the devices: Pair your mobile device with the ESP32 board using the device name
• 9. Control the LEDs: Use a Bluetooth terminal app on your mobile device to send integer values to the ESP32 board. The board will receive the values and use them to turn the LEDs on or off.

Here are the source codes:

   
      #include "BluetoothSerial.h"
#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif
byte light;
BluetoothSerial SerialBT;
    
    void setup() {
     Serial.begin(115200);
     SerialBT.begin("espCHRIS"); //Bluetooth device name
     Serial.println("The device started, now you can pair it with bluetooth!");
     pinMode(19, OUTPUT);
                }
                                        
        void loop() {
       if (SerialBT.available()) {
       light = SerialBT.read(); 
        delay(20);
           }
                                        
      if (light == '1'){
      digitalWrite(19, HIGH);
              }
        else if (light == '0'){
        digitalWrite(19, LOW);
                                         }
                                         
                                        }
   

Below video uploaded on youtube is of controlling LEDs trough bluetooth using ESP32 .