KIT INCLUDES:
- 555 Timer IC - 1
- 4017 IC - 1
- Resistor 10K - 2, 1K - 2, 220ohm - 8, 470ohm - 5
- Capacitor 10uF - 1
- Transistor 2N2222 - 2
- Led (red and white )- 2 pieces each
- Single stand Wire 2m - 1
- 12V 1A Adapter - 1
- Breadboard 840 point – 1
HARDWARE REQUIRED
- 555 Timer IC - 1
- 4017 IC - 1
- Resistor 10K - 2, 1K - 2, 220ohm - 8, 470ohm - 5
- Capacitor 10uF - 1
- Transistor 2N2222 - 2
- Led(red and white )-2 pieces each
- Single stand Wire 2m - 1
- 12V 1A Adapter - 1
- Breadboard 840 point – 1
SPECIFICATIONS
Power Supply - 12v (From 12v 1 Amp adapter)
PIN DESCRIPTION
555 timer IC
Pin |
Name |
Purpose |
1 |
GND |
Ground reference voltage, low level (0 V) |
2 |
TRIG |
The OUT pin goes high and a timing interval starts when this input falls below 1/2 of CTRL voltage (which is typically 1/3 Vcc, CTRL being 2/3 Vcc by default if CTRL is left open). In other words, OUT is high as long as the trigger low. Output of the timer totally depends upon the amplitude of the external trigger voltage applied to this pin. |
3 |
OUT |
This output is driven to approximately 1.7 V below +Vcc, or to GND. |
4 |
RESET |
A timing interval may be reset by driving this input to GND, but the timing does not begin again until RESET rises above approximately 0.7 volts. Overrides TRIG which overrides threshold. |
5 |
CTRL |
Provides “control” access to the internal voltage divider (by default, 2/3 Vcc). |
6 |
THR |
The timing (OUT high) interval ends when the voltage at threshold is greater than that at CTRL (2/3 Vcc if CTRL is open). |
7 |
DIS |
Open collector output which may discharge a capacitor between intervals. In phase with output. |
8 |
Vcc |
Positive supply voltage, which is usually between 3 and 15 V depending on the variation. |
IC 4017
The importance Pins look at the table below.
1.) Pin 16 is positive power supply and pin 8 is a ground.
The power supply range of 3 volts to 16 volts and Maximum power supply voltage at pin 1 must not much than 18 volts.
2.)Pin 13 is Clock enabled pins to controls the clock.
When it is “0” logic, the clock is enabled and the counter advances one count for each clock pulse.
When “1” logic, the clock input is stop, and the counter does nothing even when clock pulse arrive.
3.) Pin 14 is the clock triggers one count.
The clock pulse must be “clean”.
If they are “noisy” the counter may advance two or more times during each clock pulse.
4.) Pin 15 is the reset pin. Normally, it is “0”.
When made “1”, the counter is reset to “0”.
5.) Pins 1-7 and 9-11 are the decoded output pins.
The active count pin goes high and all others remain low.
6.) Pin 12 is Carry output, for the clock input of an additional counter or an external circuit that the count is complete.
Transistor 2N222
Led
CIRCUIT DESCRIPTION
- 555 Timer IC connected to the breadboard.
- Pin 1 of 555 Timer IC is GND and Pin 4 & 8 connected to the positive supply.
- Pin 2 & 6 of 555 Timer IC is connected to the each other.
- 1k Resistor 1st led connected to the positive supply and Resistor 2nd leg connected to the Pin 7 of 555 Timer IC.
- 10K Resistor 1st leg connected to the Pin 6 of 555 Timer IC and Resistor 2nd leg connected to the Pin 7 of 555 Timer IC.
- 10uF Capacitor positive leg connected to the Pin 2 of 555 Timer IC and Capacitor negative leg is GND.
- Pin 3 of 555 Timer IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the pin 14 of 4017 IC.
- Pin 16 of 4017 IC connected to the positive supply and Pin 8, 12, 13 & 15 of 4017 IC are GND.
- Pin 3 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(1st) 2N2222 2nd leg(B).
- Pin 4 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(1st) 2N2222 2nd leg(B).
- Pin 10 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(1st) 2N2222 2nd leg(B).
- Transistor(1st) 2N2222 1st leg is GND and Transistor(1st) 3rd leg connected to Led negative leg and led positive leg connected to 470 ohm Resistor and Resistor 2nd leg connected to the positive supply.
- Pin 1 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(2nd) 2N2222 2nd leg(B).
- Pin 6 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(2nd) 2N2222 2nd leg(B).
- Pin 11 of 4017 IC to connected 220 ohm Resistor and Resistor 2nd leg connected to the Transistor(2nd) 2N2222 2nd leg(B).
- Transistor(2ND) 2N2222 1st leg is GND and 3rd leg to connected led negative leg and led positive leg connected to the 470 ohm resistor and resistor 2nd led connected to the positive supply.
- Breadboard connection positive to positive and negative to negative.
WORKING
The timer here generates pulses of time period 100ms approximately. So the ON time is 50ms and OFF time is 50ms. This time duration can be changed by changing the value of capacitor.
These pulses are fed to the DECADE BINARY COUNTER. Now the decade binary counter counts the number of pulses given at the clock and lets the corresponding pin output go high, for example, if the event count is 3 then Q2 pin of counter will be high and if 5 is count the pin Q4 will be high. So for every 100ms there will be a peak, with this peak the counter memory gains by one and so is the output.
Here Q0, Q2, Q4 are connected to base of one transistor and Q5, Q7, Q9 are connected to another transistor base. The first transistor drives a pair of RED LED’s and second transistor drives a set of BLUE LED’s.
As said earlier, the counter output gets incremented by one for every 100ms until the over flow. As the overflow of count takes place, the counter resets itself and starts from zero again.
Since Q0, Q2, Q4 are controls of RED pair, they will be ON for 100ms, three times as:
Q0—LED on for 100ms
Q1---LED off for 100ms, as Q1 high every other output will be LOW, and Q1 is not connected to drive RED pair.
Q2---LED on for 100ms.
Q3---LED off for 100ms.
Q4---LED on for 100ms.
By the next clock Q5 will be high and all others will be low.
Since Q5, Q7, Q9 are so connected to drive the BLUE pair. The BLUE LED’s also will be ON for 100ms and for three times.
So we have a RED pair which blinks three times and a BLUE pair which blinks there times. These two pair blinking alternatively forms the police lights.