Red Blue Police Light Flasher Circuit

This article show how to make a Red Blue Police Light Flasher Circuit.

It uses two IC 555 chips which are very common.

Each chip run at different speed.

They connect to two LED groups in special way in like opposite direction.

This make LEDs blink one after other and back and forth and with this it looks very cool flashing.

What is a Red Blue Police Light Flasher Circuit:

Red Blue Police Light Flasher Circuit is small electronic circuit it flashes red and blue lights one by one like real police light.

People use this in toy police cars, emergency car models or hobby project for fun police light effect.

Mostly red and blue LEDs are used to make the flashing pattern.

Circuit Building:

Parts List:

Construction detail of this circuit is mentioned below:

• First put all parts same like in the circuit diagram.
• Check LED voltage and current and be sure it matches with power source.
• On PCB place two 555 ICs.
• Connect pin 1 to ground and pin 8 to positive and join pin 2 and 6 together in both ICs.
• Make both ICs work as astable flip flop and use resistor R2, R3 and capacitor C2, C3.
• Connect one side of resistor to pin 7,other side to pin 6.
• Also connect capacitor between pin 6 and 2.
• Do same for second IC2.
• We can change flashing speed and color switch speed by changing resistor and capacitor value.
• R2 and C2 change color switch time and R3 and C3 change flash speed.
• Make two LED groups.
• Connect one group to pin 3 of IC1 other group to pin 3 of IC2.
• Connect LEDs negative leg cathode to ground.
• We can change number and color of LEDs if we want.
• But total current must stay under 200mA which is max for 555 IC output.
• To control LED current adjust resistor R1.
• Connect power to PCB, positive and ground.
• Circuit can work with 12V supply also its ok between 9V to 15V.

Formulas:

Below is simple formula for Red Blue Police Light Flasher Circuit:

This circuit uses 555 IC to make LED blinking.

Three parts control the blink time: two resistors R1, R2 and one capacitor C1.

Use this formula to find how fast it flash:

Frequency = 1 / (1.1 × R1 × C1)

where:

• Frequency is in Hertz Hz
• R1 is resistor value in ohms Ω
• C1 is capacitor value in farads F

To know how long LED stay ON in one cycle then use duty cycle formula:

Duty Cycle = R2 / (R1 + R2) × 100%

where:

• Duty Cycle is in percent (%)
• R1 and R2 are resistor values in ohms Ω

Note:

These formulas are simple and are not for very complex circuit.

Actual blink time maybe not 100% same like calculation.

Warning: Be Careful About Health:

Flashing lights can be bad for some people health especially who have problem like stroke or epilepsy.

Use this LED police flasher circuit carefully and think about people who are sensitive to light.

We can make our own red blue police light flasher using this circuit, it looks nice and catches eyes.

Conclusion:

Making Red Blue Police Light Flasher Circuit for toy car is like making small disco light!

555 IC chip is special and it turns red and blue LEDs ON and OFF one by one like real police car.

This project is fun but better to do with help with an adult because some parts are very small and need careful work.

References:

Emergency vehicle lighting