A coin-based mobile charging system provides an alternative solution for all mobile users to charge their mobile phones during travel or in an emergency situation where they may not have conventional power banks. This system can also be implemented in shopping complexes and schools where mobiles are not allowed. This system is based on Arduino UNO microcontroller controls the entire system including provision of password-based security for mobile phones, once inserted into the slots. The document also focuses on various applications of this system and how this system can be integrated to add more features, sustainability and reliability in it and solve the main problems faced by people related to charging their phones. The future scope of The system also revolves around the implementation of this system in rural areas. areas where there are constant power outages.


The use of mobile phones is increasing in many folds. Therefore, loading mobile phones has become a bigger task these days. Battery power is the main concern when buying new mobile phones. The main objective of the mobile charger is to reduce the waste of electrical energy which often arises due to the negligence of the Username. Once the coin is inserted, the coin acceptor detects whether the coin is valid or no For each price unit, the power is available for a limited period only. the Arduino can calculate time-based on the number of coins inserted.

Required Hardware Components


  • ATMEGA328P Microcontroller.
  • IR Sensor
  • Relay
  • Lcd
  • charging connectors


  • Arduino compiler
  • Proteus designing software
  • Embedded c programming
  • Flash magic.

Bill of Materials

1Arduino UnoArduino UNO atmega3281https://www.amazon.com/Arduino-A000066-ARDUINO-UNO-R3/dp/B008GRTSV6
2IR SesnorIR Sesnor1ader-em18-board-with-serial-ttl-interfacing-125-khz-through-a-rs232-converter-to-pc/?src=google&kwd=&adgroup={adgroup}&devicec&campaign={campaign}&adgroup={adgroup}&keyword=&matchtype=&gclid=CjwKCAjw49qKBhAoEiwAHQVTo-i85TwixHnJAFNHLfwUknLhBVYloMe3ECBLmMFtUFrk8qGBxO0vzhoCIAQQAvD_BwE
3Relay Relay 1https://roboticsdna.in/product/rf-card-125khz-thin/
4LCD 16*2LCD 16*21https://www.thingbits.in/products/standard-lcd-16×2-display
6Jumper WiresJumper Wires40https://www.flipkart.com/arduino-female-male-dupont-20cm-jumper-wire-40pcs-interconnect-electronic-hobby-kit/p/itmf8e5ezvkequ3h?pid=EHKF8DVBG9BXZHHH&lid=LSTEHKF8DVBG9BXZHHHUGSG9J&marketplace=FLIPKART&cmpid=content_electronic-hobby-kit_14498130132_u_8965229628_gmc_pla&tgi=sem,1,G,11214002,u,,,543116155366,,,,c,,,,,,,&ef_id=CjwKCAjwndCKBhAkEiwAgSDKQYwKr3euuMpKCLDJnf-

Arduino uno

Arduino Uno is a microcontroller board based on ATmega328P (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 Analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power connector, an ICSP header, and a reboot. button. It contains everything necessary to support the microcontroller, just plug it into a computer with a USB cable or power it up with an AC-to-DC adapter or battery to get started. You can play with your Uno without worrying too much about doing something wrong, in the worst case you can replace the chip for a few dollars and start over.

“Uno” means one in Italian and was chosen to mark the release of Arduino Software (IDE) 1.0. The Uno board and version 1.0 of the Arduino software (IDE) were the reference versions of the Arduino, now evolved to newer versions. The Uno board is the first in a series of Arduino USB boards and the reference model for the Arduino platform; For an extensive list of current, outdated, or outdated boards, see the Arduino Board Index.

Tech specs

16 × 2 standard LCD screen

Do you want to add an interface to your project? Use the standard 16 × 2 alphanumeric LCD display, they are extremely common and a quick way for your project to display status messages.

An LCD (liquid crystal display) screen is an electronic display module and has a wide range of applications. A 16 × 2 LCD screen is a very basic module and is very commonly used in various devices and circuits.

A 16 × 2 LCD screen means that it can display 16 characters per line and there are 2 of those lines. On this LCD screen, each character is displayed in a 5 × 7 pixel matrix. The 16 x 2 alphanumeric dot-matrix smart display is capable of displaying 224 different characters and symbols. This LCD display has two registers, namely Command and Data. The command register stores various commands given to the screen.

The data log stores the data to be displayed. The screen control process involves placing the data that makes up the image of what you want to display in the data registers and then placing the instructions in the instruction register. In your Arduino project, the liquid crystal library simplifies this so you don’t need to know the low-level instructions. The display contrast can be adjusted by adjusting the potentiometer that will be connected through the VEE pin.

General specifications


Single-Channel Relay Module Pin Description

A relay is an electrically actuated switch. It consists of a set of input terminals for one or more control signals and a set of operating contact terminals. The switch can have any number of contacts in multiple contact forms, such as making contacts, breaking contacts, or combinations thereof.

Single Channel Relay Module Specifications

IR Sensor

An infrared (IR) sensor is an electronic device that measures and detects infrared radiation in its surrounding environment. Infrared radiation was accidentally discovered by an astronomer named William Herchel in 1800. By measuring the temperature of each colour of the light (separated by a prism), he noticed that the temperature beyond red light was higher. IR is invisible to the human eye, as its wavelength is longer than that of visible light (although it is still on the same electromagnetic spectrum). Anything that emits heat (anything that has a temperature greater than five degrees Kelvin) emits infrared radiation.

There are two types of infrared sensors: active and passive. Active infrared sensors both emit and detect infrared radiation. Active IR sensors have two parts: a light-emitting diode (LED) and a receiver. When an object comes close to the sensor, the infrared light from the LED reflects off of the object and is detected by the receiver. Active IR sensors act as proximity sensors, and they are commonly used in obstacle detection systems (such as in robots).


  • Easy to assemble and use.
  • On-board detection indication
  • The effective distance range from 2cm to 80cm.
  • A preset knob for adjusting the distance range
  • If there is an obstacle, the indicator lights up on the circuit board.


The Arduino based smartphone charging controller is implemented here, which is a simple project to control the amount of time your mobile phone charges. With this project, you can connect your phone to the charger, set the time for which your phone charges, and forget about it, as the project will automatically disconnect the power from the charger. This project is very useful for people who tend to charge the phone overnight or for those who often forget that they plugged the phone into the charger.

Final code

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int i;
void setup() {
  lcd.begin(16, 2);
  pinMode(13, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(7, INPUT);
  lcd.print("SOLAR AND COIN ");
  lcd.setCursor(0, 1);
  lcd.print("BASED MOBILE");
  lcd.setCursor(0, 0);
  lcd.print("              ");
  lcd.setCursor(0, 1);
  lcd.print("      CHARGER       ");
  lcd.setCursor(0, 0);
  lcd.print("INSERT THE COIN");
  lcd.setCursor(0, 1);
  lcd.print("                   ");


void loop() {
  lcd.setCursor(0, 0);
  lcd.print("  INSERT  COIN  ");
  lcd.setCursor(0, 1);
  lcd.print("                ");
      lcd.print(" COIN  INSERTED ");
      lcd.setCursor(0, 0);
      lcd.print("MOBILE CHARGING.");
        lcd.setCursor(0, 1);
        if(i>9)lcd.print("       ");
        else lcd.print("        ");

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