My sister and wife are in education, and the kids play a "Jeopardy" like game in the classroom. I wanted to make a circuit for them to use. After seeing several threads regarding game show circuits and attempting (unsuccessfully) to simulate many of them. I decided to attempt my own.
My circuit is for four players, and once anyone had pressed his/her button, their LED will illuminate and the circuit will lockout from any other inputs.
I used a 4013 D-type flip flop with the clock connected to a pushbutton input (more on this in the next paragraph) They clock on the rising edge. The D input is tied high, so that starting from a reset state (Q is low; Q' is high), the Q output will go high on a rising edge. The Reset inputs are held low with a pulldown resistor, and will reset when the input is brought high.
Locking out other players when one button is pressed is done by first sending the clock input through an dual input AND gate. The second input of this gate for each player is tied to the output of a quad input AND gate, whose inputs are driven through Q' from each flip flop. Thus, when one player buzzes in, his Q' will go low, all the AND gates will prevent input to any clock, thus effectively locking everyone from changing the state.
The parts I used are listed below, including part numbers from Digikey:
Qty Digikey # Description
9 CF18JT4K70CT-ND RES 4.7K OHM 1/8W 5% CF AXIAL
1 67-1153-ND LED 3MM YELLOW DIFF PANEL MOUNT
2 A31112-ND CONN HEADER VERT 2POS .100 TIN
2 S390QCT-ND RES 390 OHM 1/4W 5% CF MINI
1 708-1403-ND HOLDER BATTERY 1 CELL 9V
4 8714K-ND STDOFF HEX M/F 4-40 .250"L ALUM
1 377-1217-ND BOX ABS 4.61X4.61X2.36" BLK
4 CP-3502MJ-ND CONN AUDIO JACK 3.5MM MONO
5 450-1110-ND NO PUSHBUTTONS
1 on hand SPST SWITCH
4 751-1116-ND LED 5MM GREEN 15MCD GAP ON GAP
4 A100205-ND CONN IC SOCKET VERT 14POS TIN
1 568-1702-5-ND IC GATE AND QUAD 2INPUT 14DIP (4081)
1 568-1703-5-ND IC GATE AND DUAL 4INPUT 14DIP (4082)
2 296-2033-5-ND IC DUAL D-TYPE FLIP-FLOP 14-DIP (4013)
Attachments are included to show the schematics. They were created using ExpressSCH.
The board layout for creating the PCB is below. There is also attached a picture of an improved layout I developed.
Note that in version 2, I used a 4k7 resistor SIP instead on discrete components, as suggested by kubeek.
Also attached are the schematics for the complete circuit. The original ExpressSCH and ExpressPCB files are included in the zip file.
My circuit is for four players, and once anyone had pressed his/her button, their LED will illuminate and the circuit will lockout from any other inputs.
I used a 4013 D-type flip flop with the clock connected to a pushbutton input (more on this in the next paragraph) They clock on the rising edge. The D input is tied high, so that starting from a reset state (Q is low; Q' is high), the Q output will go high on a rising edge. The Reset inputs are held low with a pulldown resistor, and will reset when the input is brought high.
Locking out other players when one button is pressed is done by first sending the clock input through an dual input AND gate. The second input of this gate for each player is tied to the output of a quad input AND gate, whose inputs are driven through Q' from each flip flop. Thus, when one player buzzes in, his Q' will go low, all the AND gates will prevent input to any clock, thus effectively locking everyone from changing the state.
The parts I used are listed below, including part numbers from Digikey:
9 CF18JT4K70CT-ND RES 4.7K OHM 1/8W 5% CF AXIAL
1 67-1153-ND LED 3MM YELLOW DIFF PANEL MOUNT
2 A31112-ND CONN HEADER VERT 2POS .100 TIN
2 S390QCT-ND RES 390 OHM 1/4W 5% CF MINI
1 708-1403-ND HOLDER BATTERY 1 CELL 9V
4 8714K-ND STDOFF HEX M/F 4-40 .250"L ALUM
1 377-1217-ND BOX ABS 4.61X4.61X2.36" BLK
4 CP-3502MJ-ND CONN AUDIO JACK 3.5MM MONO
5 450-1110-ND NO PUSHBUTTONS
1 on hand SPST SWITCH
4 751-1116-ND LED 5MM GREEN 15MCD GAP ON GAP
4 A100205-ND CONN IC SOCKET VERT 14POS TIN
1 568-1702-5-ND IC GATE AND QUAD 2INPUT 14DIP (4081)
1 568-1703-5-ND IC GATE AND DUAL 4INPUT 14DIP (4082)
2 296-2033-5-ND IC DUAL D-TYPE FLIP-FLOP 14-DIP (4013)
Attachments are included to show the schematics. They were created using ExpressSCH.
The board layout for creating the PCB is below. There is also attached a picture of an improved layout I developed.
Note that in version 2, I used a 4k7 resistor SIP instead on discrete components, as suggested by kubeek.
Also attached are the schematics for the complete circuit. The original ExpressSCH and ExpressPCB files are included in the zip file.
Attachments
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