#include <SPI.h> // library for I2C communication

#include <Wire.h> // library for I2C communication

#include <Adafruit_GFX.h> // library for grpahics (not needed)

#include <Adafruit_SSD1306.h> // library for OLED display

#include <math.h> // library for math stuff

#include <INA226_WE.h> // library for INA226 by wollewald

#define SCREEN_WIDTH 128 // setting OLED screen size

#define SCREEN_HEIGHT 64

#define OLED_RESET 4

#define I2C_ADDRESS 0x40 // address for OLED board, you may need to change if using differnt OLED display

Adafruit_SSD1306 display(OLED_RESET);

 float shuntVoltage_mV = 0.000; // setting variables to simplify commands

 float busVoltage_V = 0.000;

  float current_A = 0.000;

 float loadVoltage_V = 0.000;

 float x;

 float y;

 float z;

INA226_WE ina226 = INA226_WE(0x40); // address for INA226, this may be different for you

void setup() {

  Wire.begin(); // initializing libraries

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);

  Serial.begin(9600);

  ina226.init();

  ina226.setResistorRange(0.005,10.0); //sets resistor to 0.005Ω (calibration required) and max current to be 10A

  ina226.waitUntilConversionCompleted();

  ina226.setConversionTime(CONV_TIME_140); // sets conversion time, this is the fastest

  ina226.setAverage(AVERAGE_256); // sets average, the higher the more accurate, but it will be slow

  pinMode(2,OUTPUT);

  }

void loop() {

  ina226.setCorrectionFactor(1); // you can use this to set resistor deviations, but I chose not to, so it's 1

  ina226.readAndClearFlags();

  shuntVoltage_mV = ina226.getShuntVoltage_mV(); // setting variables to make easier commands

  busVoltage_V = ina226.getBusVoltage_V();

  current_A = ina226.getCurrent_mA()/1000;

if (current_A <=0) { // this if else statment is used to prevent the display from showing negative current values

    x = 0.000;

  }

  else{

    x = current_A;

  }

if (busVoltage_V >= 10){ //these if else statments are to align the cursors for the voltage and current if one of                               

    z = 18;              // them passes 10 as this would make the display look even

  }

  else {

    z = 30;

  }

  if ( current_A >= 10){

    y = 18;

  }

  else {

    y = 30;

  }

  display.clearDisplay();

  display.setTextColor(WHITE);

  display.setTextSize(2);

  display.setCursor(z,0); // sets where the display starts writing

  display.print(busVoltage_V,3); // prints and sets loadvoltage to be measured to the third decimal

  display.setCursor(110,0);

  display.print("V      ");

  display.setTextColor(WHITE);

  display.setTextSize(2);

  display.setCursor(y,18);

  display.print(x,3);

  display.setCursor(110,18);

  display.print("A      ");

  display.display(); // command to display info

  Serial.println(shuntVoltage_mV,5); // use this line to check serial monitor to calibrate sensor

 }