sketch
` //>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
// ARDUINO BATTERY CAPACITY TESTER
//Version-2.1
//by deba168,INDIA // The code is taken from Hesam Moshiri ( Battery capacity measurement using Arduino [Lithium-NiMH-NiCd] - Technology - PCBway )
//Dated : 02/02/2022
//
//Dated : 29/02/2020
//Added code to read a band gap reference connected to analog pin A1,
// thus allowing measurement of Vcc and avoiding the need to measure it using a multimeter
//Replaced 1 ohm 5% resistor with 1 ohm 1% power resistor
//Modified code to compute actual current draw based on desired values. Measurements
// using ammeter show computed values within 2 milliamps of measured
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#include<JC_Button.h>
#include <Adafruit_SSD1306.h>
#define DEBUG 0 // Binary Treatment 0=Nothing, 1=Early, 2=Running Voltages, 4=Finish
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET 4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
void timerInterrupt();
void Display_UP_DOWN();//Debugging support
void Print_DEBUG_4();//Debugging support
const float Low_BAT_level = 2.7;// Threshold for stopping test
//Desired Current steps with a 3R load (R7)
int Current [] = {0,50,100,200,300,400,500,600,700,800,900,1000};
int PWM [] = {0, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50};
int Array_Size;// calculated during setup
const byte PWM_Pin = 10;
const byte Buzzer = 9;
const int BAT_Pin = A0;
const int Vref_Pin = A1;//Pin to which Band Gap Reference is attached
int Current_Value = 0; // Selected Current value for test
int PWM_Value = 0;// Value of PWM during test
int PWM_Index = 0;// Index into PWM array during test
unsigned long Capacity;
float Capacity_f;
int ADC_Value = 0;
float Vref_Voltage = 1.215; // LM385BLP-1.2 Band Gap Reference voltage
float Vcc = 5.32; // Voltage of Arduino 5V pin ( Measured during setup using Band Gap Reference )
float BAT_Voltage = 0;
float Resistance = 1.0; // Value of R3 Power Resistor
float sample = 0;
byte Hour = 0, Minute = 0, Second = 0;
bool calc = false, Done = false, Report_Info = true;
Button UP_Button(2, 25, false, true);
Button Down_Button(3, 25, false, true);
// string values for reporting intermediate information
const int VAL_MAX = 10;
char val_0[VAL_MAX]={""};
char val_2[VAL_MAX]={""};
void setup () {//Setup
Serial.begin(38400);
pinMode(PWM_Pin, OUTPUT);
pinMode(Buzzer, OUTPUT);
analogWrite(PWM_Pin, PWM_Value);
UP_Button.begin();
Down_Button.begin();
display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setCursor(12,25);
display.print("Open Green Energy");
display.display();
delay(3000);
display.clearDisplay();
display.setTextSize(2);
display.setCursor(2,15);
display.print("Adj Curr:");
display.setCursor(2,40);
display.print("UP/Down:");
display.print("0");
display.setCursor(2,55);
display.setTextSize(1);
#if (DEBUG == 1 || DEBUG == 5)
Serial.println("\nStart of calculations");
#endif
Array_Size = sizeof(Current)/2;
//Read voltages of Band Gap Reference and use it to calculate actual Vcc
float fTemp=0.0;
for(int i=0;i< 100;i++)
{
fTemp=fTemp+analogRead(Vref_Pin); //read the Band Gap Reference voltage
delay (2);
}
fTemp=fTemp/100.0;
Vcc = Vref_Voltage * 1024.0 / fTemp;
// Convert desired current levels to PWM using actual Vcc
// Convert PWM values back to actual current levels
// While measuring actual current I discovered that the actual draw is
// (PWM + 1)/256 rather than PWM/255 as indicated in Arduino documentation
int iTemp;
for (int i=0;i<Array_Size;i++)
{
iTemp = int( Resistance * Current[i] * 256.0 / Vcc / 1000.0 - 1.0 + 0.5 ); // desired current to nearest PWM
iTemp = min(iTemp,255);
iTemp = max(iTemp,0);
Current[i] = int( (iTemp+1) * Vcc / 256.0 / Resistance * 1000.0); // actual current for PWM
PWM[i] = iTemp;//Save PWM in array
}
//Include Threshold and Vcc in startup display
dtostrf(Low_BAT_level, 5, 3, val_0);
dtostrf(Vcc, 5, 3, val_2);
display.print("Thr=");
display.print(val_0);
display.print("v, Vcc=");
display.print(val_2);
display.display();
display.setTextSize(2);
}//Setup
//************************* End of Setup function *******************************
void loop() {
if (Report_Info)
{//Report_Info
Serial.flush();
#if (DEBUG == 1 || DEBUG == 5)
// Serial.println("Measured Vcc Voltage: " + String(Vcc) + " volts");
Serial.print("Threshold: ");
Serial.print(Low_BAT_level,3);
Serial.println(" volts");
Serial.print("R3 Resistance: ");
Serial.print(Resistance,3);
Serial.println(" ohms");
Serial.print("Measured Vcc Voltage: ");
Serial.print(Vcc,4);
Serial.println(" volts");
sample = 0.0;
Serial.println("Index Actual(mA) PWM");
for (int i=0;i<Array_Size;i++)
{
// Serial.println( "["+String(i)+"]="+String(Current[i])+" mA PWM["+String(i)+"]="+String(PWM[i]) );
Serial.print("[");
Serial.print(i);
Serial.print("]");
Serial.print(" ");
Serial.print(Current[i],DEC);
Serial.print(" ");
Serial.print(PWM[i],DEC);
Serial.println(" ");
}
#endif
Report_Info = false;
}//Report_Info
UP_Button.read();
Down_Button.read();
if (UP_Button.wasReleased() && PWM_Index < (Array_Size-1) && calc == false)
{
PWM_Value = PWM[++PWM_Index];
analogWrite(PWM_Pin,PWM_Value);
Display_UP_DOWN();
}
if (Down_Button.wasReleased() && PWM_Index > 0 && calc == false)
{
PWM_Value = PWM[--PWM_Index];
analogWrite(PWM_Pin,PWM_Value);
Display_UP_DOWN();
}
if (UP_Button.pressedFor (1000) && calc == false)
{
digitalWrite(Buzzer, HIGH);
delay(100);
digitalWrite(Buzzer, LOW);
display.clearDisplay();
timerInterrupt();
}
}
//************************* End of Loop function *******************************
void timerInterrupt(){
calc = true;
while (Done == false) {//(Done == false)
Second ++;
if (Second == 60) {
Second = 0;
Minute ++;
}
if (Minute == 60) {
Minute = 0;
Hour ++;
}
//************ Measuring Battery Voltage ***********
for(int i=0;i< 100;i++)
{
sample=sample+analogRead(BAT_Pin); //read the Battery voltage
delay (2);
}
sample=sample/100;
BAT_Voltage = sample * Vcc / 1024.0;
//*********************************************
display.clearDisplay();
display.setTextSize(2);
display.setCursor(20,5);
// display.print(String(Hour) + ":" + String(Minute) + ":" + String(Second));
display.print(Hour);
display.print(":");
display.print(Minute);
display.print(":");
display.print(Second);
display.setTextSize(1);
display.setCursor(0,25);
display.print("Disch Curr: ");
// display.print(String(Current[PWM_Index])+"mA");
display.print(Current_Value);
display.print("mA");
display.setCursor(2,40);
// display.print("Bat Volt:" + String(BAT_Voltage)+"V" );
display.print("Bat Volt:");
display.print(BAT_Voltage,3);
display.print("V");
// When total seconds is greater than 32767 the statement below did not work until the byte values
// Hour, Minute and Second were cast to an unsigned long. Apparently the compiler cast the byte
// values to an "int" first which cannot represent 32768 correctly
Capacity = ((unsigned long)Hour * 3600) + ((unsigned long)Minute * 60) + (unsigned long)Second;
Capacity_f = ((float)Capacity * Current_Value) / 3600.0;
display.setCursor(2, 55);
// display.print("Capacity:" + String(Capacity) + "mAh");
display.print("Capacity:");
display.print(Capacity_f,1);
display.print("mAh");
display.display();
#if (DEBUG == 4 || DEBUG == 2)
Print_DEBUG_4();
#endif
if (BAT_Voltage < Low_BAT_level)
{//BAT_Voltage < Low_BAT_level
#if (DEBUG == 4 || DEBUG == 5)
Serial.println("\nCurrent_Value PWM_Value");
Serial.print(Current_Value);
Serial.print(" ");
Serial.println(PWM_Value);
Serial.println("\nHour Minute Second PWM_Index");
Serial.print(Hour);
Serial.print(" ");
Serial.print(Minute);
Serial.print(" ");
Serial.print(Second);
Serial.print(" ");
Serial.println(PWM_Index);
#endif
// When total seconds is greater than 32767 the statement below did not work until the byte values
// Hour, Minute and Second were cast to an unsigned long. Apparently the compiler cast the byte
// values to an "int" first which cannot represent 32768 correctly
Capacity = ((unsigned long)Hour * 3600) + ((unsigned long)Minute * 60) + (unsigned long)Second;
#if (DEBUG == 4 || DEBUG == 5)
Serial.println("Capacity HMS");
Serial.println(Capacity);
#endif
Capacity_f = ((float)Capacity * Current_Value) / 3600.0;
#if (DEBUG == 4 || DEBUG == 5)
Serial.println("Capacity HMS*PWM");
Serial.println(Capacity_f,1);
#endif
display.clearDisplay();
display.setTextSize(2);
display.setCursor(2,15);
display.print("Capacity:");
display.setCursor(2,40);
// display.print(String(Capacity) + "mAh");
display.print(Capacity_f,1);
display.print("mAh");
display.display();
Done = true;
PWM_Value = 0;
analogWrite(PWM_Pin, PWM_Value);
digitalWrite(Buzzer, HIGH);
delay(100);
digitalWrite(Buzzer, LOW);
delay(100);
digitalWrite(Buzzer, HIGH);
delay(100);
digitalWrite(Buzzer, LOW);
delay(100);
}//BAT_Voltage < Low_BAT_level
delay(1000);
}//(Done == false)
}// timerInterrupt
void Display_UP_DOWN()
{//Display_UP_DOWN()
Current_Value = Current[PWM_Index];
display.clearDisplay();
display.setCursor(2,25);
display.print("Curr:");
display.print(Current_Value);
display.print("mA ");
display.setCursor(2,40);
display.print("PWM=");
display.print(PWM_Value);
display.display();
}//Display_UP_DOWN()
void Print_DEBUG_4()
{//Print_DEBUG_4()
Serial.print(Hour);
Serial.print(":");
Serial.print(Minute);
Serial.print(":");
Serial.print(Second);
Serial.print(" ");
Serial.print(BAT_Voltage,3);
Serial.print("v ");
Serial.print(Capacity_f,1);
Serial.println("mAh");
}//Print_DEBUG_4()`
