Battery Monitor

A simple app to measure the battery level (%) and voltage (mV).

You need to add 2 Resistors to the Backpack.

GND -[330kOhm]- A1 -[100kOhm]- VBAT

I protected the PCB with some tape, because if you touch the Voltage Divider or A1 it influences the readout.

Download: Battery.zip

//importe the Gamebuino library and the gb object
#include 
#define ADC_PIN A1
#define ADC_PIN_OFFSET 165 //in mV (measured ADC from µC)-(Measured voltage on Pin with Multimeter)
#define ADC_PIN_MAXVOLT 3201
#define BATTERY_FULL 4190 //in mV measured when Battery Full on VBAT
#define BATTERY_EMPTY 3000 //in mV on LiPo dont go Lower!
/*

Schematic:

GND -[330kOhm]- A1 -[100kOhm]- VBAT

When the Battery Voltage is 4.200V the Voltage on A1 is 3.223V

*/

void setup() {

// put your setup code here, to run once:

gb.begin();

pinMode(ADC_PIN, INPUT);

}
int adcPinVolt = 0, batteryVolt = 0;

byte batteryPercent = 0;

void loop() {

// put your main code here, to run repeatedly:

while (!gb.update());

gb.display.clear();
adcPinVolt = ((3300 / 1023) * analogRead(ADC_PIN)) + ADC_PIN_OFFSET;

batteryVolt = map(adcPinVolt, 0, ADC_PIN_MAXVOLT, 0, BATTERY_FULL);

batteryPercent = map(batteryVolt, BATTERY_EMPTY, BATTERY_FULL, 0, 100);

if (batteryPercent > 100)

batteryPercent = 100;
gb.display.drawRect(10, 20, 60, 34);

gb.display.drawLine(70, 31, 70, 42);

gb.display.drawLine(71, 32, 71, 41);

if (batteryPercent >= 60)

gb.display.setColor(GREEN);

else if (batteryPercent >= 30 && batteryPercent <= 59)

gb.display.setColor(YELLOW);

else

gb.display.setColor(RED);

gb.display.fillRect(11, 21, map(batteryPercent, 0 , 100, 0, 58), 32);
gb.display.setColor(WHITE);

gb.display.println("Battery");

gb.display.setCursor(30, 30);

gb.display.print(batteryVolt);

gb.display.println("mV");

gb.display.setCursor(32, 36);

gb.display.print(batteryPercent);

gb.display.println("%");

delay(500);

}