Mobile overcharging or Laptop overcharging are common problems. People plug in their laptop or mobile for charging overnight which unintentionally leads to overcharging of the device and reducing the battery life. This project allows avoiding overcharging by letting the user set a timer for charging the device. Apart from this home-based application, the project can also be used in industry environment where over-heating of machines has to be avoided by automating the time of their operations.This ideas was suggested by Jaya Prakash
This project implements this application by switching off a connected device to the circuit according to a user defined timer. The project is build on an Arduino UNO Board and utilizes RTC for tracking real time and a relay circuit to implement switching off power supply. The human interface is provided via LCD display and 4-switch keypad is used to feed timer input to the system. Any device running or charging on 230V AC can be programmatically switched off just by connecting the device to the supply via this project.
The project works in the following manner -:
1) The device will be initially cut short of the power supply as it is connected via circuit.
2) The Arduino based circuit will show the current time on the LCD display with the help of RTC.
3) As the user will set time in the circuit, a timer will get activated and power supply to the device will be switched on.
4) The timer can be set by a keypad of four switches - SET Switch to initiate setting process, INCREASE switch to increase hour or minute value of the timer, NEXT switch to skip hours setting to the minutes setting and a RESET switch to reset timer.
5) The current time will be tracked using the RTC and compared with the user defined time to initiate switching off operation.
6) As the current time equates to the user defined time, the circuit will operate the relay to switch off the power supply.
Components Required -:
• Arduino UNO
• RTC module-DC1307
• 16x2 LCD
• 12v Relay
• BC 547 transistor
• 1K ohm resisters -7
• Push to ON switch-4
• Voltage regulator -7805
• LED -5mm RED- 2
• Wire to carry 2A,230v AC
• Two pin Plug
• Three pin holder
As seen in the block diagram the major components of the circuit are - :
1) Power Supply Regulator
2) Relay Circuit as Power Switching Unit
3) RTC Module DS1307
4) LCD Display
6) Arduino Boar
The Arduino Board is the programmable Unit that will be controlling the entire functionality of the circuit and every module will be interfaced to it. The circuit will be connected the following way -:
1) Power Supply: While the device will be running on AC supply, the circuit will require 12V and 5V DC supply. The 12V supply will be provided via battery and supplied to 12V relay and voltage regulator. The other components will need a 5V DC supply which will be provided via 7805 voltage regulator that is converting the input 12V supply to 5V DC.
2) Relay Circuit: The device is connected to the circuit via a 12V relay. The relay is connected to the pin 7 of Arduino board via BS547 transistor circuit in a common emitter configuration.
3) RTC Module: DS1307 RTC module is used in the circuit. The 5V DC supply and ground to the RTC module are provided by the 7805 voltage regulator. The SDA and SCL pins of the RTC are connected to the SDA and SCL pins of Arduino Board respectively. Learn more about interfacing and programming RTC with Arduino here.
4) LCD Display: The 16X2 LCD display is connected to the Arduino board by connecting its data pins to pins 2 to 5 of the Arduino board. The RS and RW pin of LCD is connected to pins 12 and 11 of the Arduino UNO respectively. The E pin of the LCD is grounded.
The standard code library for interfacing Arduino UNO and Arduino Pro Mini are used in the project to program LCD with the board. The code library works as expected. ]]>Learn more about LCD interfacing with the Arduino UNO]]>.
5) 4-switch Keypad: For timer input, a 4-switch keypad is interfaced to the circuit. The keypad comprises 4 push-to-on switches connected to the A0, A1, A2 and A3 pins of the Arduino UNO through 1K ohm pull-up resistors. The switches connected to A0, A1, A2 and A3 pins are designated to NEXT, INC, SET and RESET operations respectively in the code.
How the Circuit Works -: