Mitch K
Published © CC BY-NC-SA

3.7v LiPo Battery Charger Monitor

This battery charger monitor uses an OLED display & Blynk to show you its charge current, bus voltage, load voltage & elapsed time.

IntermediateShowcase (no instructions)4 hours787
3.7v LiPo Battery Charger Monitor

Things used in this project

Hardware components

INA219 DC Current Sensor
×1
ESP8266 ESP-01
Espressif ESP8266 ESP-01
×1
Capacitor 220 µF
Capacitor 220 µF
×1
3.3V Regulator
×1
Basic 1.0A DC LiPo Charger
×1
OLED I2C Display 1.3"
×1

Software apps and online services

Blynk
Blynk

Story

Read more

Schematics

Circuit

Code

DC Charger

Arduino
#include <Wire.h>
#include <Adafruit_INA219.h>
#include <BlynkSimpleEsp8266.h>
#include <ESP8266WiFi.h>
#include <U8g2lib.h>

extern "C" {
#include "user_interface.h"
}


U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);

Adafruit_INA219 ina219;

char auth[] = "";
char ssid[] = "IoT";
char pass[] = "";


float shuntvoltage = 0.0;
float busvoltage = 0.0;
float current_mA = 0.0;
float loadvoltage = 0.0;

float cumshuntvoltage = 0.0;
float cumbusvoltage = 0.0;
float cumcurrent_mA = 0.0;
float cumloadvoltage = 0.0;
float prevMA = 0.0;
unsigned int count = 0;


unsigned int hourTime = 0;
unsigned int minTime = 0;
unsigned int secTime = 0;

char * text1 = "Bus Voltage: ";
char * text2 = "Load Voltage: ";
char * text3 = "Current: ";
char * text4 = "Charge Time: ";

byte startTime = 0;

unsigned long time1 = 0;
unsigned long time2 = 0;



void setup()
{
	// Serial.begin(9600);

	Blynk.begin(auth, ssid, pass);


	Wire.begin(2, 0);

	u8g2.begin();
	u8g2.enableUTF8Print();
	prepare();


	ina219.begin();
}




void loop()
{
	Blynk.run();

	time1 = millis();
	cumshuntvoltage = 0;
	cumbusvoltage = 0;
	cumcurrent_mA = 0;
	cumloadvoltage = 0;
	count = 0;




	while (millis() - time1 < 1000)
	{

		shuntvoltage = ina219.getShuntVoltage_mV();
		busvoltage = ina219.getBusVoltage_V();
		current_mA = ina219.getCurrent_mA();
		loadvoltage = busvoltage + ( shuntvoltage / 1000 );

		cumshuntvoltage += shuntvoltage;
		cumbusvoltage += busvoltage;
		cumcurrent_mA += current_mA;
		cumloadvoltage += loadvoltage;

		count++;
		delay(5);
	}

	shuntvoltage = cumshuntvoltage / count;
	busvoltage = cumbusvoltage / count;
	current_mA = cumcurrent_mA / count;
	loadvoltage = cumloadvoltage / count;



	if (prevMA < 0.1 && current_mA > 10.0)
	{
		time2 = millis();

		startTime = 1;

		hourTime = 0;
		minTime = 0;
	}

	if (prevMA > 4.0 && current_mA < 10.0)
	{
		startTime = 0;
	}



	if (startTime)
	{
		secTime = (millis() - time2) / 1000;

		if (secTime > 59)
		{
			minTime++;
			time2 = millis();
		}

		if (minTime > 59)
		{
			hourTime++;
			minTime = 0;
		}


	}



	u8g2.clearBuffer();

	u8g2.drawStr(0, 0, text1);
	u8g2.setCursor(90, 0);
	u8g2.print(busvoltage);
	u8g2.print(" v");

	u8g2.drawStr(0, 15, text2);
	u8g2.setCursor(90, 15);
	u8g2.print(loadvoltage);
	u8g2.print(" v");

	u8g2.drawStr(0, 30, text3);
	u8g2.setCursor(78, 30);
	u8g2.print(current_mA, 1);
	u8g2.print(" mA");

	u8g2.drawStr(0, 45, text4);
	u8g2.setCursor(85, 45);
	u8g2.print(hourTime);
	u8g2.print(":");
	u8g2.print(minTime);
	u8g2.print(":");
	u8g2.print(secTime);



	u8g2.sendBuffer();


	String timeString =  String(hourTime) + ":" + String(minTime) + ":" + String(secTime);

	Blynk.virtualWrite(V0, busvoltage);
	Blynk.virtualWrite(V1, shuntvoltage);
	Blynk.virtualWrite(V2, loadvoltage);
	Blynk.virtualWrite(V3, current_mA);
	Blynk.virtualWrite(V4, current_mA);
	Blynk.virtualWrite(V5, busvoltage);
	Blynk.virtualWrite(V6, count);
	Blynk.virtualWrite(V7, timeString);
	Blynk.virtualWrite(V21, wifi_station_get_rssi());

	prevMA = current_mA;

} // loop




void prepare()
{
	u8g2.setFont(u8g2_font_6x10_tf);
	u8g2.setFontRefHeightExtendedText();
	u8g2.setDrawColor(1);
	u8g2.setFontPosTop();
	u8g2.setFontDirection(0);
}



BLYNK_WRITE(V20)
{
	byte restartChip = param.asInt();

	delay(500);

	if (restartChip == 1)
	{
		ESP.restart();
	}
}

Credits

Mitch K

Mitch K

2 projects • 14 followers

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