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Police LED Flasher with 555 Timer

Police lights are flashing lights, which are a type of emergency vehicle lighting. You can find similar flashing lights in ambulances, fire brigades, military vehicles, etc. Basically, they are visually captivating and often convey the state of the urgency of their task to the other road users. In this electronics project, we will make a simple Police LED flasher with two 555 timer integrated circuits.

Let's make it!

Components List

The following components are needed for this project.

  1. IC1, IC2 - 555 Timer IC (2 pcs)
  2. R1, R2 - 1MΩ 0.25W Resistor (2 pcs)
  3. R3 - 270Ω 0.25W Resistor (1 pcs)
  4. C1 - 100uF 25V Capacitor (1 pcs)
  5. C2 - 1uF 50V Capacitor (1 pcs)
  6. C3 - 100nF Non-Polar Capacitor (1 pcs)
  7. D1, D2 - 5mm Blue LED (As per required)
  8. D3, D4 - 5mm Red LED (As per required)
  9. 9V Battery (1 pcs)
  10. Breadboard/PCB (1 pcs)
  11. Wire (As per required)

Circuit Diagram

Schematic of police LED flasher circuit with 555 timer IC shown below.

Circuit Explanation

In this circuit, both (U1, U2) 555 ICs work as an astable flip-flop and each IC with a different frequency. Their outputs pin-3 are connected to antiparallel two groups of 5mm red and blue LEDs.

The flasher circuit produces alternating series of strobes of LEDs of each group.

You may adjust the frequency and nature of flashing by changing the values of the C2, C3, R1, and R2.

  • U1 555 timer circuit: R1 and C2 affect the frequency of switching colors.
  • U2 555 timer circuit: R2 and C3 affect the flash rate.

You can also use a different number and different colors of LEDs in this flasher circuit. But it is necessary to adjust the value of R3 not to exceed the maximum current of LEDs. The current also must not exceed 200mA (max output) current of circuit 555.

This police LED flasher circuit can be powered by any 3.7 - 12V, ≥2A supply.

Demo and Testing

In this demo video, you will see the test of the Police LED Flasher with two 555 Timer IC. I power the circuit with a 9-volt battery, and it starts flashing immediately.

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