10-04-2017, 08:54 PM
fastest finger first circuit diagram using microcontroller pdf
Fastest Finger first circuit is basically used in quiz type games where the reaction speed of a participant is significant. The circuit enables us to identify who responded first to the question by triggering a visual and audio indication.
Components Required
1. 1 x ATMega16 development board
2. 1 x Seven Segment display
3. 8 x 330 ohms Resistor
4. 9 x Momentary Switches (8 Teams + 1 Reset switch)
5. 1 x Buzzer
6. 1 x BC547 Transistor
Description
The circuit uses a buzzer to produce the audio signal and a seven segment display for visual indication. The display shows the corresponding team number which pressed the buzzer first. The brain of this circuit is an ATMega16 microcontroller which can run at a maximum speed of 16MHz and so there will be no question of clash between any two contestants until and unless their reaction time was same in order of microseconds which is impossible.
Seven Segment Display
It consists of seven LEDs named a, b, c, d, e, f and g which when turned ON or OFF in a particular pattern displays a decimal number from 0 to 9 or alphabets A to F. The seven LEDs either have a common cathode or common anode configuration in order to reduce the number of pins.
The quiz buzzer systems are widely used in school, colleges and TV programs. The team which presses the buzzer earliest is entitled to give the answer. At times it becomes very difficult to identify which team has pressed the button when two teams press the buzzer within a very small time gap. In such cases the decision can be biased due to human intervention. The quiz buzzer presented here takes care of the aforesaid problem. This quiz buzzer disables the other inputs as soon as the first buzzer is pressed. This quiz buzzer can be used for a maximum of eight teams. It is build around 8051 microcontroller (AT89C51).