Circuit Documentation

Summary

This circuit is designed to charge a 18650 battery using a solar panel and a TP4056 battery charging protection module. It also includes a 555 timer-based circuit for additional functionality, a voltage sensor, and an ESP32 microcontroller to monitor and display the voltage on an I2C display. The ESP32 also sends the voltage data to a Blynk application for remote monitoring.

Component List

1. TP4056 Battery Charging Protection Module (Type C)

   • Pins: OUT +, B+, B-, OUT -, +, -
   • Description: Used for charging and protecting the 18650 battery.

2. Solar Panel

   • Pins: +, -
   • Description: Provides power to charge the battery.

3. Battery 18650

   • Pins: +, -
   • Description: Stores energy from the solar panel.

4. 555 Timer

   • Pins: GND, TRIG, OUT, ~RESET, VCC, DIS, THR, CTRL
   • Description: Used for timing and control purposes.

5. Electrolytic Capacitor

   • Pins: -, +
   • Description: Stores electrical energy.
   • Properties: Capacitance: 0.000001 Farads

6. Resistor

   • Pins: pin1, pin2
   • Description: Limits current flow.
   • Properties: Resistance: 200 Ohms

7. Diode

   • Pins: cathode, anode
   • Description: Allows current to flow in one direction only.

8. Copper Coil - 30 Turns

   • Pins: 1 PIN, 2 PIN
   • Description: Used for inductance in the circuit.

9. Bridge - 1N4007

   • Pins: 1 INPUT, 2 INPUT, + PIN, - PIN
   • Description: Converts AC to DC.

10. 7805 Voltage Regulator

    • Pins: Vin, Gnd, Vout
    • Description: Regulates voltage to 5V.

11. Voltage Sensor DC 25V

    • Pins: +, -, output, gnd, vcc
    • Description: Measures voltage up to 25V.

12. ESP32

    • Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, VIN, 3V3, D15, D2, D4, RX2, TX2, D5, D18, D19, D21, RX0, TX0, D22, D23, BOOT
    • Description: Microcontroller for processing and communication.

13. I2C Display

    • Pins: GND, VCC, SDL, SCL
    • Description: Displays voltage readings.

Wiring Details

TP4056 Battery Charging Protection Module (Type C)

• B+ connected to + of Solar Panel
• B- connected to - of Solar Panel
• + connected to + of Battery 18650, ~RESET and VCC of 555 Timer, and pin2 of Resistor
• - connected to - of Battery 18650, GND of 555 Timer, - of Electrolytic Capacitor, and 1 PIN of Copper Coil - 30 Turns

Solar Panel

• + connected to B+ of TP4056 Battery Charging Protection Module
• - connected to B- of TP4056 Battery Charging Protection Module

Battery 18650

• + connected to + of TP4056 Battery Charging Protection Module
• - connected to - of TP4056 Battery Charging Protection Module

555 Timer

• GND connected to - of TP4056 Battery Charging Protection Module
• TRIG connected to cathode of Diode, + of Electrolytic Capacitor, and pin2 of Resistor
• OUT not connected
• ~RESET connected to + of TP4056 Battery Charging Protection Module
• VCC connected to + of TP4056 Battery Charging Protection Module
• DIS connected to anode of Diode, pin1 of Resistor, and pin1 of another Resistor
• THR connected to 2 PIN of Copper Coil - 30 Turns
• CTRL connected to + of Electrolytic Capacitor

Electrolytic Capacitor

• - connected to - of TP4056 Battery Charging Protection Module and 1 PIN of Copper Coil - 30 Turns
• + connected to TRIG of 555 Timer and cathode of Diode

Resistor

• pin1 connected to DIS of 555 Timer and anode of Diode
• pin2 connected to + of TP4056 Battery Charging Protection Module and TRIG of 555 Timer

Diode

• cathode connected to TRIG of 555 Timer and + of Electrolytic Capacitor
• anode connected to DIS of 555 Timer and pin1 of Resistor

Copper Coil - 30 Turns

• 1 PIN connected to - of TP4056 Battery Charging Protection Module and - of Electrolytic Capacitor
• 2 PIN connected to THR of 555 Timer

Bridge - 1N4007

• + PIN connected to 1 PIN of Copper Coil - 30 Turns
• - PIN connected to 2 PIN of Copper Coil - 30 Turns
• 1 INPUT connected to + of Electrolytic Capacitor, Gnd of 7805 Voltage Regulator, and gnd of Voltage Sensor DC 25V
• 2 INPUT connected to - of Electrolytic Capacitor and Vin of 7805 Voltage Regulator

7805 Voltage Regulator

• Vin connected to 2 INPUT of Bridge - 1N4007
• Gnd connected to 1 INPUT of Bridge - 1N4007
• Vout connected to vcc of Voltage Sensor DC 25V

Voltage Sensor DC 25V

• + connected to 3V3 of ESP32
• - connected to GND of ESP32
• output connected to D35 of ESP32
• gnd connected to 1 INPUT of Bridge - 1N4007
• vcc connected to Vout of 7805 Voltage Regulator

ESP32

• 3V3 connected to + of Voltage Sensor DC 25V
• GND connected to - of Voltage Sensor DC 25V and GND of I2C Display
• D35 connected to output of Voltage Sensor DC 25V
• VIN connected to VCC of I2C Display
• D21 connected to SDL of I2C Display
• D22 connected to SCL of I2C Display

I2C Display

• GND connected to GND of ESP32
• VCC connected to VIN of ESP32
• SDL connected to D21 of ESP32
• SCL connected to D22 of ESP32

Documented Code

#define BLYNK_TEMPLATE_ID "TMPL2Tfn-9Jrz"
#define BLYNK_TEMPLATE_NAME "dc voltmeter"
#define BLYNK_AUTH_TOKEN "xbbqQafjumDlL4D5eYwjtAAMN1DFeAzT"
#define BLYNK_PRINT Serial

#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);

// Calibration factor for DC voltage with 5V reference
const float vCalibration = 5.0 / 4095.0; // Adjust this value as needed

// Blynk and WiFi credentials
char auth[] = BLYNK_AUTH_TOKEN; // Blynk authentication token
const char* ssid = "C1"; // Your WiFi network SSID
const char* pass = "12345678"; // Your WiFi network password

void setup() {
  Serial.begin(115200);
  Blynk.begin(auth, ssid, pass);

  // Initialize the LCD
  lcd.begin();
  // Display startup message
  lcd.setCursor(3, 0);
  lcd.print("group ");
  lcd.setCursor(3, 1);
  lcd.print("  45    ");
  delay(3000);  // Wait for 3 seconds

  // Clear the LCD and display "DC Voltmeter"