Whenever we go to vote for elections we come to see electronic voting machines. In this project we are going to design and develop a simple voting machine by using ATmega32A microcontroller. Although we can use the controller to get more than 32 people voting machine, to keep everything simple we are going to make a voting machine for a size of four people.We will have four buttons for four people and whenever a button is pressed, a vote goes for the corresponding person and the number of votes each person gets shown on LCD.
Power supply (5v)
JHD_162ALCD (16×2 LCD)
100nF capacitor (five pieces), 100uF capacitor (connected across power supply)
10KΩ resistor (five pieces).
Atmel studio 6.1
progisp or flash magic.
As shown in the above electronic voting machine circuit, PORTA of ATMEGA32 microcontroller is connected to data port LCD. Here one should remember to disable the JTAG communication in PORTC of ATMEGA by changing the fuse bytes, if one wants to use the PORTC as a normal communication port. In 16×2 LCD, there are 16 pins over all if there is a back light, if there is no back light there will be 14 pins. One can power or leave the back light pins. Now in the 14 pins there are 8 data pins (7-14 or D0-D7), 2 power supply pins (1&2 or VSS&VDD or gnd&+5v), 3rd pin for contrast control (VEE-controls how thick the characters should be shown), 3 control pins (RS&RW&E).
In the circuit, you can observe that I have only taken two control pins as this give the flexibility of better understanding. The contrast bit and READ/WRITE are not often used so they can be shorted to ground. This puts LCD in highest contrast and read mode. We just need to control ENABLE and RS pins to send characters and data accordingly.
For more detail: Microcontroller Based Electronic Voting Machine