Solar Powered Charging Station Circuit Documentation

Summary

The Solar Powered Charging Station is an environmentally friendly solution that utilizes solar energy to charge electronic devices. The system is designed to activate a charging session when a bottle is placed on a load cell, indicating recycling participation. The charging session lasts for 5 minutes. The circuit comprises a solar panel, battery, charge controller, voltage regulator, load cell with an amplifier, an Arduino UNO microcontroller, an LCD screen for user interface, a relay to control the power to the charging circuit, and a PowerBoost module for stable 5V output.

Component List

Solar Panel

• Description: Converts sunlight into electrical energy.
• Pins: +, -

12v 7ah Battery

• Description: Stores electrical energy for later use.
• Pins: 12v +, 12v -

Solar Charge Controller

• Description: Manages the power going into the battery bank from the solar array.
• Pins: Solar Cell +, Solar Cell -, Battery +, Battery -, Load +, Load -

XL4015 5A DC Buck Step-down Converter

• Description: Steps down voltage to a lower level.
• Pins: Output +, Output -, Input +, Input -

SparkFun Load Cell Amplifier - HX711

• Description: Amplifies the signal from the load cell.
• Pins: GND, CLK, DAT, VCC, YLW, GRN, WHT, BLK, RED, B-, B+

LCD screen 16x2 I2C

• Description: Displays information to the user.
• Pins: SCL, SDA, VCC, GND

PowerBoost 1000 Basic Terminal USB

• Description: Provides a 5V output from battery power.
• Pins: VBAT, GND, ENABLE, LBO, 5.0V

Load Cell - Red/white/black/green

• Description: Measures the weight of the bottle placed on it.
• Pins: E+, A-, E-, A+

Arduino UNO

• Description: The main microcontroller board that controls the system.
• Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0 to A5, SCL, SDA, AREF, D13 to D0

5v Relay

• Description: Electrically operated switch to control the charging circuit.
• Pins: Normally Open, Common terminal, Normally Closed, In, GND, VCC

Wiring Details

Solar Panel

• + connected to Solar Charge Controller Solar Cell +
• - connected to Solar Charge Controller Solar Cell -

12v 7ah Battery

• 12v + connected to Solar Charge Controller Battery + and XL4015 Output +
• 12v - connected to Solar Charge Controller Battery - and XL4015 Output -

Solar Charge Controller

• Load + not detailed in the provided net list.
• Load - not detailed in the provided net list.

XL4015 5A DC Buck Step-down Converter

• Input + connected to 5v Relay Normally Open and PowerBoost 5.0V
• Input - connected to PowerBoost GND

SparkFun Load Cell Amplifier - HX711

• GND connected to Arduino UNO GND
• CLK connected to Arduino UNO A0
• DAT connected to Arduino UNO A1
• VCC connected to 5v Relay VCC, Arduino UNO 5V, and LCD screen VCC
• YLW, GRN, WHT, BLK, RED, B-, B+ connected to corresponding Load Cell pins.

LCD screen 16x2 I2C

• SCL connected to Arduino UNO A5
• SDA connected to Arduino UNO A4
• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND

PowerBoost 1000 Basic Terminal USB

• 5.0V connected to 5v Relay Normally Open and XL4015 Input +
• GND connected to XL4015 Input -, 5v Relay GND, and Arduino UNO GND

Load Cell - Red/white/black/green

• A+ connected to HX711 GRN
• A- connected to HX711 WHT
• E- connected to HX711 BLK
• E+ connected to HX711 RED

Arduino UNO

• GND connected to HX711 GND, LCD screen GND, PowerBoost GND, and 5v Relay GND
• A0 connected to HX711 CLK
• A1 connected to HX711 DAT
• A4 connected to LCD screen SDA
• A5 connected to LCD screen SCL
• 5V connected to HX711 VCC, LCD screen VCC, and 5v Relay VCC
• D7 connected to 5v Relay In

5v Relay

• Normally Open connected to XL4015 Input + and PowerBoost 5.0V
• Common terminal not detailed in the provided net list.
• Normally Closed not detailed in the provided net list.
• In connected to Arduino UNO D7
• GND connected to PowerBoost GND and Arduino UNO GND
• VCC connected to HX711 VCC and Arduino UNO 5V

Documented Code

/*
 * Solar Powered Charging Station
 * This Arduino sketch controls a solar-powered charging station. When a bottle
 * is placed on the load cell, the system grants 5 minutes of phone charging
 * time. The system uses an LCD to display status messages and a relay to
 * control the charging circuit.
 */

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Pin definitions
const int loadCellDataPin = A1;
const int loadCellClockPin = A0;
const int relayPin = 7;

// Load cell calibration factor
const float calibrationFactor = -7050.0;

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Initialize LCD
  lcd.begin();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Charging Station");

  // Initialize relay pin
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);

  // Initialize load cell
  scale.begin(loadCellDataPin, loadCellClockPin);
  scale.set_scale(calibrationFactor);
  scale.tare();
}

void loop() {
  // Read load cell value
  float weight = scale.get_units(10);

  // Check if a bottle is placed
  if (weight > 50) { // Adjust threshold as needed
    lcd.setCursor(0, 1);
    lcd.print("Charging...");
    digitalWrite(relayPin, HIGH);
    delay(300000); // 5 minutes
    digitalWrite(relayPin, LOW);
    lcd.setCursor(0, 1);
    lcd.print("Done");
    delay(2000);
    lcd.setCursor(0, 1);
    lcd.print("                ");
  }
  delay(1000);
}

This code is responsible for controlling the charging station. It reads the weight from the load cell and, if the weight exceeds a certain threshold, it activates the relay to allow charging. The LCD screen displays the status of the charging session. The code includes setup for the load cell, LCD, and relay, as well as the main loop that checks the load cell and controls the relay.