16-07-2015, 02:33 PM
I want pdf of fastest finger first using microcrontroller
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fastest finger first using at89c51 pdf file
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I want pdf of fastest finger first using microcrontroller
17-07-2015, 10:54 AM
fastest finger first using at89c51 pdf file
Introduction:
Now a days quiz-type game shows are increasingly becoming popular on television. In such quiz games , fastest finger first indicators (FFFIs) are used to test the contestants reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button.
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).
This quiz buzzer system has eight input pins corresponding to eight teams. The output is displayed on a seven segment display(interfaced with microcontroller), which shows the number corresponding to the team which has pressed the button first. A buzzer is also sounded for a small duration to give an acoustic alarm. The connections of the seven segment, input pins and output pins is shown in the circuit diagram.
For more details, refer ‘seven segment interfacing ’. There are a total of nine input pins. Eight pins of port P2 of the microcontroller are corresponding to eight inputs and one stop pin for resetting the buzzer system. On the output side a seven segment is connected to display the corresponding output number. There is also a provision for sounding a buzzer for a small duration.
When the system starts, the seven segment does not displays any output. The microcontroller keeps scanning the input pins. As soon as any one of the inputs is pressed, the buzzer sounds for a small duration. The seven segment displays the number corresponding to the input pressed. Now even if any other input pin is pressed, there will be no effect on the system till the time the stop pin is pressed to reset the system.
Objective:
The fastest finger first circuit presented here determines as to which of the four contestants first pressed the button and locks out the remaining three entries of other three members. Simultaneously, an audio alarm (buzzer) and the correct decimal number display of the corresponding contestant are activated.
Working:
When a contestant presses his switch, the corresponding output of latch IC2 (7475) changes its logic state from 1 to 0. The combinational circuitry comprising dual 4-input NAND gates of IC3 (7420) locks out subsequent entries by producing
the appropriate latch-disable signal. Priority encoder IC4 (74147) encodes the active-low input condition into the
corresponding binary coded decimal (BCD) number output. The outputs of IC4 after inversion by inverter gates inside hex inverter 74LS04 (IC5) are coupled to BCDto-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common anode 7-segment LED display (DIS.1, FND507 or LT542). The audio alarm generator comprises clock oscillator IC7 (555), whose output drives a loudspeaker.
The oscillator frequency can be varied with the help of preset VR1. Logic 0 state at one of the outputs of IC2 produces logic 1 input condition at pin 4 of IC7, thereby enabling the audio
oscillator. IC7 needs +12V DC supply for sufficient alarm level. The remaining circuit operates on regulated +5V DC supply,
which is obtained using IC1 (7805). Once the organizer identifies the contestant who pressed the switch first, he disables the audio alarm and at the same time forces the digital display to ‘0’ by pressing reset push button S5. With a slight modification, this circuit can accommodate more than four contestants.
Conclusion:
This project is an electronic quiz buzzer. Fastest finger first indicators are used to test the player’s reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button. In the buzzer round of quiz contest, the question is thrown to all the teams. The person who knows the answer hits the buzzer first and then answers the question. Some times two or more players hit the buzzer almost simultaneously and it is very difficult to detect which of the team has pressed the buzzer first. In television shows, where the whole event is recorded, the actions are replayed in slow motion to detect the first hit. Such slow motions are possible only where huge funds are available to conduct the show. For this reason buzzer rounds are avoided for quiz contests held in colleges.
But this indicator reduces the probability of any error in detecting who pressed the buzzer first. Thus, in this project we have concluded all the components for the set up of this indicator.
Introduction:
Now a days quiz-type game shows are increasingly becoming popular on television. In such quiz games , fastest finger first indicators (FFFIs) are used to test the contestants reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button.
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).
This quiz buzzer system has eight input pins corresponding to eight teams. The output is displayed on a seven segment display(interfaced with microcontroller), which shows the number corresponding to the team which has pressed the button first. A buzzer is also sounded for a small duration to give an acoustic alarm. The connections of the seven segment, input pins and output pins is shown in the circuit diagram.
For more details, refer ‘seven segment interfacing ’. There are a total of nine input pins. Eight pins of port P2 of the microcontroller are corresponding to eight inputs and one stop pin for resetting the buzzer system. On the output side a seven segment is connected to display the corresponding output number. There is also a provision for sounding a buzzer for a small duration.
When the system starts, the seven segment does not displays any output. The microcontroller keeps scanning the input pins. As soon as any one of the inputs is pressed, the buzzer sounds for a small duration. The seven segment displays the number corresponding to the input pressed. Now even if any other input pin is pressed, there will be no effect on the system till the time the stop pin is pressed to reset the system.
Objective:
The fastest finger first circuit presented here determines as to which of the four contestants first pressed the button and locks out the remaining three entries of other three members. Simultaneously, an audio alarm (buzzer) and the correct decimal number display of the corresponding contestant are activated.
Working:
When a contestant presses his switch, the corresponding output of latch IC2 (7475) changes its logic state from 1 to 0. The combinational circuitry comprising dual 4-input NAND gates of IC3 (7420) locks out subsequent entries by producing
the appropriate latch-disable signal. Priority encoder IC4 (74147) encodes the active-low input condition into the
corresponding binary coded decimal (BCD) number output. The outputs of IC4 after inversion by inverter gates inside hex inverter 74LS04 (IC5) are coupled to BCDto-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common anode 7-segment LED display (DIS.1, FND507 or LT542). The audio alarm generator comprises clock oscillator IC7 (555), whose output drives a loudspeaker.
The oscillator frequency can be varied with the help of preset VR1. Logic 0 state at one of the outputs of IC2 produces logic 1 input condition at pin 4 of IC7, thereby enabling the audio
oscillator. IC7 needs +12V DC supply for sufficient alarm level. The remaining circuit operates on regulated +5V DC supply,
which is obtained using IC1 (7805). Once the organizer identifies the contestant who pressed the switch first, he disables the audio alarm and at the same time forces the digital display to ‘0’ by pressing reset push button S5. With a slight modification, this circuit can accommodate more than four contestants.
Conclusion:
This project is an electronic quiz buzzer. Fastest finger first indicators are used to test the player’s reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button. In the buzzer round of quiz contest, the question is thrown to all the teams. The person who knows the answer hits the buzzer first and then answers the question. Some times two or more players hit the buzzer almost simultaneously and it is very difficult to detect which of the team has pressed the buzzer first. In television shows, where the whole event is recorded, the actions are replayed in slow motion to detect the first hit. Such slow motions are possible only where huge funds are available to conduct the show. For this reason buzzer rounds are avoided for quiz contests held in colleges.
But this indicator reduces the probability of any error in detecting who pressed the buzzer first. Thus, in this project we have concluded all the components for the set up of this indicator.
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