Many times people make choice by flipping coin, but this method is not always fair but sometimes it give biased result and therefore, to fix this we can use Electronic Coin Toss Circuit using IC 555 and JK Flip-Flop.
It works like real coin flip using digital technology and LED.
This circuit has two main parts:
In the circuit diagram below IC1 555 runs as astable multivibrator at 10Hz and IC2 74LS76 set to toggle and works as needed.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | 1M | 1 |
| 47k | 2 | |
| 470Ω | 2 | |
| 100Ω | 2 | |
| Capacitors | Ceramic 0.1µF | 1 |
| Electrolytic 1µF 16V | 1 | |
| Semiconductors | IC 555 Timer | 1 |
| IC 74LS76 JK Flip-Flop | 1 | |
| Transistor BC547 | 1 | |
| Tactile Push Button Switch | 1 | |
| LED Heads Red 5mm 20mA | 1 | |
| TLED ails Green 5mm 20mA | 1 |
IC1 555 Timer works as astable multivibrator as it makes square wave signal ON/OFF at set speed and it keeps sending pulses again and again.
Also, transistor Q1 BC547 works like switch, when we press button S1 as it turns ON the JK flip-flop IC2 74LS76.
Then button S1 gives trigger pulse to IC2 and IC2 holds the toss result and controls LEDs, this is because IC1 runs fast IC2 changes state fast and looks random.
After that, flip-flop output controls two LEDs with one LED lights up based on final flip-flop state and S1 starts the toss.
As a result, a high speed pulse makes LED choice look random like fair coin flip.
Note:
- Red LED (Heads) is pin 14
- Green LED (Tails) is pin 15
How to Build:
To build a Electronic Coin Toss Circuit using IC 555 and JK Flip-Flop follow below steps for connection:
- First, connect pin 1 of IC1 555 to GND
- Join pin 2 and pin 6 of IC1 together
- Then connect C1 positive to pin 2 and negative to GND
- Next, connect pin 3 of IC1 to base of Q1 BC547 using R3
- Now, connect pin 4 and pin 8 of IC1 to +5V supply
- After that, connect pin 5 of IC1 to GND using capacitor C2
- Also, place resistor R2 between pin 6 and pin and also place another R2 between pin 7 and +5V
- Further, connect collector of Q1 to +5V using R4 and connect emitter of Q1 to GND
- Then connect pin 1 of IC2 74LS76 to collector of Q1 through S1 switch and then add R5 from pin 1 of IC2 to GND
- Next, connect pin 4, pin 5 and pin 16 of IC2 to +5V
- Connect pin 13 of IC2 to GN and then connect pin 14 of IC2 to +5V through LED2 (Red Heads) and R6
- Finally, connect pin 15 of IC2 to +5V through LED1 (Green Tails) and R7
Conclusion:
Overall, this Electronic Coin Toss Circuit using IC 555 and JK Flip-Flop removes unfair coin flips and it gives random and equal result, and then LEDs show Heads or Tails.
Also, it is good project for students and hobby people to learn timers and flip-flops in digital circuits.