Playing with My Son, Him Being the Policeman and Me Being the Bad Guy

Policemen are awesome right? I’m talking about good policemen and not the bad ones here. My father was a retired Policeman. He is my childhood hero, one of the best. In my childhood years, I’ve seen a lot of movies where the main protagonists are policemen, or in the military.

Today, my son and I plays a lot of role-playing game. Recently, we played the role of bad guy-policeman. He was the Policemen, and of course, I was the bad guy. We had so much fun playing the game. He always catches me. :)

So to make the game more awesome and exciting, I am planning to build this small toy for our plays. As we all know, police have the police vehicle which are equipped with loud sirens. I wanted to create a police car lights for his toy car, like the one on the image below.

The police car lights projects will be designed using a 555 timer. This circuit will simulate the police car lights by alternate flashing.

Here’s the project description take from the original posthere:

PROJECT DESCRIPTION

This circuit simulates the police car lights by alternate flashing. This circuit flashes red LEDs for three times and blue LED’s for three times. This flashing action performs continuously.

This circuit uses 555 timer and a decade counter. Here, 555 timer runs in astable mode. Decade counter 4017 counts the incoming pulses that is for first pulse Q0 becomes high and for second pulse Q1 becomes high and so on again for 10th pulse Q0 state becomes high.

Police Lights Circuit using 555 Timer:

Circuit Components:

• NE555 timer
• 4017 decade counter
• 1n4148 diodes – 6
• 1 k Resistor(1/4 watt) – 1
• 22 k Resistor(1/4 watt) – 1
• 470 ohm Resistor(1/4 watt) – 8
• 2.2 uF Electrolytic capacitor(16V) – 1
• Blue LED’s – 2
• Red LED’s – 2
• 9 V battery – 1
• Connecting wires
• 555 Timer Based Police Lights Circuit Design

555 Timer. Here 555 Timer runs in free running mode. It produces pulses whose width can be varied. 2nd and 6th pins are shorted to allow triggering after every cycle. 4th pin is connected 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 supply voltage range is -0.5 to +22 V. The high pulse on the reset pin clears the count to zero. The speed of operation of this IC is up to 10 MHz. The output states (Q0, Q2, Q4) are ORed to flash the blue LED’s 3 times and the states Q5, Q7 and Q9 are ORed to flash the red LED’s 3 times.

Based on the output 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 high voltage.

After connecting the whole circuit, apply power to it. Now observe the LEDs carefully. You will find that red led’s flashes 3 times and blue led’s flashes 3 times and this process repeats.