Making a fun electrical coin flipper is shown by this circuit.
Just like when you flip a coin and while pressing a button it causes a small silicon chip in a computer to quickly give the ‘heads’ or ‘tails’ answer!
What is a Heads or Tails Decision Maker Circuit:
A ‘heads or tails’ decision maker circuit is an electrical device designed to choose a random between two options which is often represented by the letters ‘heads’ or ‘tails.’
The concept is similar to flipping a coin to make the correct decision.
By using logic gates and electronic components to provide a random result this circuit solves simple problems in an entertaining and fascinating way.
Circuit Working:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistors | 100k 1/4 watt | 1 |
| 470Ω 1/4 watt | 1 | |
| 150k 1/4 watt | 2 | |
| Capacitors | Ceramic 4.7nF | 1 |
| Ceramic 100pF | 2 | |
| Electrolytic 1µF 25V | 1 | |
| Semiconductors | Transistors BC557 | 2 |
| IC4093 (N1 to N4) | 1 | |
| LEDs Red / Green | 2 | |
| Switches ON / OFF Switch | 1 | |
| Push to OFF Switch | 1 | |
| Battery 9V | 1 |
The flip flop involving N3 and N4 through N2 is controlled by a square wave generator that is made up of gates N1, R1 and C1.
Through transistors T1 and T2 the flip flops outputs alternately turn on LEDs D1 and D2.
The LEDs blink quickly when the button is pressed.
As soon as the button is pressed one particular LED stays ON while the other goes completely dark.
These LEDs are often labeled as ‘heads or tails’ providing a decision that is really random.
Even though a third LED was considered first since they were are not sure, it failed once it became clear that experts nowadays are capable of making many judgments on their own.
The circuit is very sensitive which ensures that the ‘heads and tails’ output is actually correct and completely random.
Although there may be many different types of hobby electrical circuits but these are the ones that are being shown here.
Formulas:
Under the following assumptions a simple formula for NAND gate oscillators that gives an estimated frequency (f) is obtained:
Time constants that are equivalent for draining and charging:
This shows that the resistor and capacitor values are the same for both the charging and discharging paths (R1 = R2 and C1 = C2).
NAND gate performance at its best:
This ignores the propagation delay inside the gate.
The following calculation is based on these assumptions:
f = 1.44 / (R * C)
where,
- The oscillations f frequency expressed in hertz (Hz).
- Ohms (Ω) of R resistance value.
- Value of C capacitance in farads (F).
Note:
The actual frequency could differ much from this estimate because of power supply changes, gate propagation delay and non-ideal component behavior.
Circuit modeling software or oscilloscope data is used to estimate the oscillation frequency more accurately.
How to Build:
To build a Simple Heads or Tails Decision Maker Circuit follow the below mentioned connections steps:
Get the silicon chips ready:
- Using silicon chips on the breadboard create the digital logic gates.
- As necessary connect the inputs and outputs.
Generator of Square Waves:
- Use Gates N1, R1 and C1 to create the square wave generator.
- The flip flop will be controlled by this.
Flip Flop Configuration:
- Use the NAND gates N3 and N4 to connect the flip flop.
- Make sure there are two states that alternate in the output.
LED Management:
- To control LEDs D1 and D2 transistors T1 and T2 should be used.
- In order to switch between ON and OFF states connect them.
Use of Push Buttons:
- The push button should be connected to the circuit.
- A button should be pressed to start the decision making process.
Source of Power:
- Connect a proper power source to the circuit.
- Batteries or any suitable power source can be used for this.
- Press the button and watch the LED change to test the circuit.
- Make sure the outcome of the decision seems random.
Notes:
Keep in mind to use the right resistor, capacitor and other component values according to the specifications of the chips and other parts while designing the circuit.
Before building the circuit verify your connections and if possible, one can test it.
Conclusion:
There are several uses for this kind of Simple Heads or Tails Decision Maker Circuit including solving disputes, making simple choices and providing some kind of difficulty into games or other activities.
This creative use of electrical components is similar to the uncertainty of a coin flip.
We would welcome ones thoughtful input on any that have been ignored for next innovations.