555Timer: Knight Rider

The knight Rider circuit is a dynamic lighting system featuring a 555 timer and a CD4017 decade counter. In this circuit the 555 timer serves as an oscillator, allowing us to adjust the circuit pulsing speed. to complete this effect, we will also be using the CD4017 decade counter to oscillate along its 10 flipflops.

By the end of this project, you will have learned to construct a light bar using 6 LEDs, each connected to the outputs of the decade counter. This will emulate the front lights of KITT, a robotic car from the 1986 TV series, Knight Rider

Supplies

• breadboard or powered breadboard
• 9v battery (only if you are using a normal breadboard)
• 555 timer
• decade counter (CD 4017)
• 6 LEDs (your color choice)
• 1 x 330 resistor
• 1 x 22k resistor
• 1 x micro-farad capacitor
• 1 x 550k potentiometer Variable resistor

In the next section we will discuss the 2 major components of this the circuit. The 555 timer and the decade counter (CD 4017)

Step 1: The 555 Timer

This project will use the 555 Timer IC (integrated circuit) as the central oscillator. this will drive the oscillation of the LEDs. by adjusting the values of R1 and R2 (by using a potentiometer) in conjunction with the capacitor, the oscillators pulse frequency can be controlled precisely. The speed of the oscillator pulses will determine how fast the LEDs light up back and forth. Both R1 and R2 will are used to set the frequency of the oscillator.

Below is the link a video that describes the counter in more detail, as well as a data sheet:

How 555 timers Work - The Learning Circuit (youtube.com)

ne555.pdf (ti.com)

Step 2: Decade Counter (CD 4017)

The CD4017 is a decade counter, meaning that it counts from 0-9, these 10 outputs are also called Q0-Q9. The 6 LEDs will be connected to each of these outputs with the other 4 being used to move the effect back in the opposite direction. This component can best be described as a series of 10D flip-flops. When this flip flop is 0 then that represents the low voltage, and when it is 1 than it is a high voltage. Once the count has gone all the way up to 10 then the count reset back down to 0. This decade counter is used when we want a large number of counts, but space and power are limited. These counters are also used for creating digital display systems and counters, as well as pulse generations.

Below is the link a video that describes the counter in more detail, as well as a data sheet:

How Decade Counters Work - The Learning Circuit (youtube.com)

schs027c.pdf (ti.com)

Step 3: Decade Counter Pins

The graph above is a guide to the pin connections on the decade counter. below is a more in-depth description of these connections:

• Clock pin (CLK) - increases the counter every time one pins has voltage applied to it. As the count increases the output pins get high one by one. After the 10th input pulse (Q9) the counter will reset and start from the 0 pin again (Q0). charging the pin form low to high will increase the counter and start the cycle over again.
• Pins Q0-Q9 - as the counter increases the output pins increase on after the other. For the purpose of this project each of these has an LED at each pin
• Clock Inhibit Pin (CI) - this pin sets the counter back to 0.
• Carry-Out Pin (Co) - this reaches low to high when the counter reaches 10 and then resets back to 0. it will stay high for 5 pulses, then will be low again.
• VDD & GND pin - these pins apply adequate volts to the counter (3-15v)

Step 4: How Should the Circuit Work ?

555 Timer as an Oscillator:

• The 555 Timer functions as an oscillator, generating a continuous series of pulses at a frequency determined by the values of the resistors and capacitor that are connected to it.
• Each of these pules serve as clock signals for the decade counter, each controlling the speed at which the LEDs illuminate creating the visual effect of the taillights of a car passing by.

CD4017 Decade Counter:

• The CD4017 is a decade counter that progresses through ten output pins (Q0-Q9) sequentially with each clock pulse received from the 555 timer's output.
• As the clock pulses are applied, the counter increments from one output pin to the next on in the sequence (Q0-->Q1-->Q2..-->Q9), lighting up the corresponding LEDs connected to each on those pins.
• when the counter reached the 10th output (Q9), it resets back to the initial pin (Q0) with the next clock pulse, completing one full cycle.

LED Effect:

• Each output pin (Q0-Q9) of the decade counter is connected to an LED. As the counter progresses, the LEDs light up sequentially, creating an effect of front lights of the car from the 1982 TV series, K.I.T.T (Knight Industries Two Thousand) modeled after a 1982 Pontiac Trans Am.

Step 5: Assembly

Resistors and Ground Connection:

• Connect the negative pins of all 6 resistors to the ground rail on the breadboard.

Decade Counter Setup:

• Ground pins 15,13,8 of the decade counter

LED and Resistor Config

• Connect R1 to the first LEDs positive terminal then connect each subsequent LEDs positive terminal to the previous LEDs negative terminal.
• Connect R2 to the las LEDs positive terminal.
• Attach the first resistor (R1) to pin 3 of the decade counter.
• connect diodes from pins 2,4,7 & 10 of the decade counter to the positive terminals of LEDs, making sure each LED is connected to a separate pin
• connect the final LED to pin 1 of the decade counter.

555 Timer Connection

• Ground pin 1
• connect pins 8&7 of the timer to pin 16(VDD) to the power supply.
• connect pins 2&6 of the timer together.
• connect pins 1&2 of the potentiometer to pin 6 of the timer and connect pin 3 of the potentiometer to pin 7 of the timer.
• connect the capacitor between pins 1 and 2 of the 555 timer.

Power Supply

• Finally connect the breadboard to the positive terminal of the 9v battery to power the circuit.

Step 6: Conclusion

In this project we have designed and constructed a knight rider circuit, combining a 555 timer, as decade counter and LEDs to create a lighting display. The 555 timer serves as an oscillator, generating clock pulses that drive the decade counter. As the counter progresses LEDs connected to its output pins light up sequentially, creating the knight rider effect. throughout this project we have learned about the 555 timer and its uses in conjunction with the decade counter. This project can be scaled up to be used in an automotive fashion, such as in the 1986 TV series Knight Rider.