1. Introduction : 

Learn how to build a temperature monitoring system using the STM8S microcontroller, LM35 temperature sensor, and a 7-segment display. We'll walk you through each step, from assembling the hardware to writing code in STM8S, ensuring you gain hands-on experience in creating your own electronic masterpiece. Subscribe now for a journey into the world of DIY electronics!

2. Circuit Diagram :

3. Setup Steps : 

3.1 Install Arduino

1. 1. Visit the Arduino Website:
      Go to the official Arduino website at https://www.arduino.cc/.
   2. Navigate to the Software Page:
      Hover over the "Software" tab in the top menu, and click on "Downloads."
   3. Download Arduino IDE:
      Click on the "Windows Installer" link to download the Arduino IDE for Windows.

3.2  Install STM8S board manager and Flash the code

1. Start the Arduino-IDE. In File->Preferences, Settings tab, enter

https://github.com/akashkapashia/stm8_arduino/raw/master/package_sduino_stm8_index.json

as an Additional Boards Manager URL.

2. Open Tools->Board:...->Boards Manager

• • • Find Sduino by typing 'sd' into the search line
    • Click on the list entry
    • Click on Install.
    • Now you should find a new entry STM8S Boards in the list at Tools->Board:...

3. Choose STM8S103F3 Breakout Board from the list
Open : File >> Open >> Select the Attached .ino file
compile it by hitting Verify

3.3 Code

#define A_PIN PC5
#define B_PIN PD2
#define C_PIN PD3
#define D_PIN PD1
#define E_PIN PC6
#define F_PIN PC4
#define G_PIN PC7

#define S1_PIN PB4
#define S2_PIN PA3
#define S3_PIN PB5

#define LM35_INPUT_PIN PD6

// Define the digits for 0-9
const int digits[11][7] = {
  {1, 1, 1, 1, 1, 1, 0}, // 0
  {0, 1, 1, 0, 0, 0, 0}, // 1
  {1, 1, 0, 1, 1, 0, 1}, // 2
  {1, 1, 1, 1, 0, 0, 1}, // 3
  {0, 1, 1, 0, 0, 1, 1}, // 4
  {1, 0, 1, 1, 0, 1, 1}, // 5
  {1, 0, 1, 1, 1, 1, 1}, // 6
  {1, 1, 1, 0, 0, 0, 0}, // 7
  {1, 1, 1, 1, 1, 1, 1}, // 8
  {1, 1, 1, 1, 0, 1, 1}, // 9
  {1, 0, 0, 1, 1, 1, 0}  // c (C for Degree c)
};

float lm35_voltage = 0;
float average_temp = 0;
float temperature_degree_c = 0;

int raw_adc_reading = 0;
// 5000 = 5V
int ref_voltage = 5000;
// 10 bit ADC 1 << 10 = 2 ^ 10 = 1024
int adc_bit_size = 1 << 10;
int average_temp_sample_size = 10;

// Function to display a digit on a specific display
void displayDigit(int digit, int display_pin) {
  int num = 0, nums = 0;
  int digits_pins[7] = {A_PIN, B_PIN, C_PIN, D_PIN, E_PIN, F_PIN, G_PIN};
  
  for(num = 0; num < 7; num++)
  {
    digitalWrite(digits_pins[num], 0);
  }

  for(num = 0; num < 7; num++)
  {
    digitalWrite(digits_pins[num], digits[digit][num]);
  }
  // Select the display
  digitalWrite(S1_PIN, display_pin == 1 ?  LOW : HIGH);
  digitalWrite(S2_PIN, display_pin == 2 ?  LOW : HIGH);
  digitalWrite(S3_PIN, display_pin == 3 ?  LOW : HIGH);
}

// Function to display a 2-digit number on the 7-segment display
void displayNumberWithDegreeC(int number) {
  int digit1 = number % 10;
  int digit2 = (number / 10) % 10;
  // Display the digits on each display, one at a time
 
  displayDigit(digit1, 1);
  delay(5); // Adjust delay as needed
  displayDigit(digit2, 2);
  delay(5); // Adjust delay as needed
  displayDigit(10, 3);
  delay(1); // Adjust delay as needed
}

void setup() {
  // Set pin modes
  pinMode(A_PIN, OUTPUT);
  pinMode(B_PIN, OUTPUT);
  pinMode(C_PIN, OUTPUT);
  pinMode(D_PIN, OUTPUT);
  pinMode(E_PIN, OUTPUT);
  pinMode(F_PIN, OUTPUT);
  pinMode(G_PIN, OUTPUT);

  pinMode(S1_PIN, OUTPUT);
  pinMode(S2_PIN, OUTPUT);
  pinMode(S3_PIN, OUTPUT);

  //Disabling the PNP Transistor pin to turn on base by default
  digitalWrite(S1_PIN, 1);
  digitalWrite(S2_PIN, 1);
  digitalWrite(S3_PIN, 1);

  //Disabling the NPN Transistor pin to turn off base by default
  digitalWrite(A_PIN, 0);
  digitalWrite(B_PIN, 0);
  digitalWrite(C_PIN, 0);
  digitalWrite(D_PIN, 0);
  digitalWrite(E_PIN, 0);
  digitalWrite(F_PIN, 0);
  digitalWrite(G_PIN, 0);
}

void loop()
{
  for(int avg = 0; avg < average_temp_sample_size; avg++) 
  {
    raw_adc_reading = analogRead(LM35_INPUT_PIN);
    // Convert the reading into voltage:
    // Convert digital data into analog by multiplying by 5000 and dividing by 1024
    lm35_voltage = raw_adc_reading * (ref_voltage / adc_bit_size);
    // Convert the voltage into the temperature in degree Celsius:
    float temperature_degree_c = lm35_voltage / 10;
    average_temp = average_temp + temperature_degree_c; 
  }
  average_temp = average_temp / average_temp_sample_size;
  // Example: Display the number 123
  displayNumberWithDegreeC(average_temp);
}

3. Video Step by Step Tutorial :