On this problem, I will current you tips about the way to design Police Lights using 555 Timer IC and CD4017 Counter IC. This circuit simulates the police car lights by alternately flashing the LEDs. This circuit flashes Pink LEDs for Three occasions and Blue LEDs for Three occasions and this flashing movement repeats consistently.
Police Lights are flashing lights which are a type of emergency automotive lighting. You may additionally uncover associated flashing lights in ambulances, fireside division, military cars and so forth. They’re visually fascinating and sometimes convey the state of urgency of their exercise to the alternative avenue prospects.
On this problem, we’ll merely take the seen facet of the police lights and implement them in our private means. The circuit makes use of 555 timer and a decade counter IC CD4017. Proper right here, the 555 timer runs in Astable mode. Decade counter 4017 counts the incoming pulses and prompts its outputs i.e. for the first pulse Q0 turns into extreme and for second pulse Q1 turns into extreme and so forth as soon as extra for 10th pulse Q0 state turns into extreme.
555 Timer Based Police Lights Circuit Principle
Proper right here 555 timer produces regular pulses by way of pin 3. The width of these pulses shall be assorted by numerous the resistance (R1,R2 ) or capacitance (C1). These pulses are given as enter to the final decade counter. For every incoming pulse the output state of the final decade counter is get incremented.
- For 1st pulse – Q0 extreme – blue led’s glow
- For 2nd pulse – Q1 extreme (no connection) – all led’s off
- For third pulse – Q2 extreme – blue led’s glow
- For 4th pulse – Q3 extreme – all led’s off
- For fifth pulse – This fall extreme – blue led’s glow
- For sixth pulse – Q5 extreme – pink led’s glow , blue led’s off
- Subsequently blue led’s flashes for Three cases.
- For seventh pulse – Q6 extreme – all led’s off
- For eighth pulse – Q7 extreme – pink led’s glow
- For ninth pulse – Q8 extreme – all led’s off
- For 10th pulse – Q9 extreme – pink led’s glow
- For 11th pulse – Q0 extreme – blue led’s glow, pink led’s off
Subsequently, pink LEDs flash for Three cases. This course of repeats consistently.
Have you ever learnt – Simple strategies to Assemble Police Siren Circuit using NE555 Timer?
Circuit Diagram of Police Lights using 555 Timer
- 555 Timer IC
- 4017 Decade Counter IC
- 1KΩ Resistor (1/4 watt) – 3
- 22KΩ Resistor (1/4 watt) – 1
- 470 ohm Resistor (1/4 watt) – 6
- 2.2µF Electrolytic capacitor (16V) – 1
- BC547 NPN Transistors – 2
- Blue LEDs – 2
- Pink LEDs – 2
- 9V battery – 1
- Connecting wires
555 Timer based Police Lights Circuit Design
Proper right here, 555 timer runs in free working mode i.e. Astable Mode. It produces pulses whose width shall be assorted. 2nd and sixth pins are shorted to allow triggering after every cycle. 4th pin is linked to Vcc to avoid sudden resets.
4017 Decade Counter
It is a 10 bit counter with ten decoded outputs. It counts the incoming pulses. The provision voltage differ is -0.5 to +22V. The extreme pulse on the reset pin clears the rely to zero. The rate of operation of this IC is as a lot as 10 Mhz.
The ouput states (Q0,Q2,This fall) are configured to flash the blue LED’s Three cases and the states Q5, Q7 and Q9 are configured to flash the pink LED’s Three cases.
Based on the outputs of 4017 IC, two transistors (NPN) switches the LED’s ON and OFF.
Resistors R3, R4, R5, R6 are used to protect the LED’s from extreme voltage.
Circuit Simulation Video
Simple strategies to Operate Police Lights Circuit?
- Apply vitality to the circuit.
- Now observe the LED’s, pink led’s flashes Three cases and blue led’s flashes Three cases and this course of repeats.
- For those who want to set the fully completely different time delays for LED’s then fluctuate the resistance (R1, R2) or capacitance (C1).
555 Timer based Police Lights Circuit Functions
- This circuit used as an indicator for police autos.
- We’ll use it as LED flasher circuit by making some modifications.
Limitations of Police Lights Circuit
- The values of the resistors R1, R2 and capacitor C1 must be an identical to get good flashing.