03-04-2017, 04:51 PM
Which is software used in smart automatic street light system using ic 555 and LDR....
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automatic street light mini project using ic555
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Which is software used in smart automatic street light system using ic 555 and LDR....
13-04-2017, 12:58 PM
No manual operation is required to turn it on and off. When there is a need for light that turns on automatically. When the darkness rises to a certain level, then the sensor circuit is activated and lights up and when there is another light source, ie during the day, the street light goes out. The sensitivity of the street light can also be adjusted.
Principle :
This circuit uses a popular timer IC 555. IC 555 is connected as a comparator with pin-6 connected to the positive rail, the output goes high (1) when the trigger pin 2 is at a level lower than 1/3 of The supply voltage. On the contrary, the output goes low (0) when it is above level 1/3. Such small changes in the voltage of the pin-2 are sufficient to change the output level (pin-3) from 1 to 0 and 0 to 1. The output has only two high and low states and can not remain in any intermediate stage. It is powered by a 6V battery for portable use. The circuit is economical in energy consumption. Pin 4, 6 and 8 are connected to the positive supply and pin 1 is connected to ground. To detect the present of an object we have used LDR and a light source.
LDR is a special type of resistance whose value depends on the brightness of the light that falls on it. It has a resistance of about 1 mega ohm when it is in total darkness, but a resistance of only about 5k ohms when the brightness is illuminated. It responds to a large part of the spectrum of light. We have made a potential divider circuit with LDR and 100K of variable resistance connected in series. We know that the voltage is directly proportional to the conductance so more voltage will be obtained from this splitter when LDR is receiving light and low voltage in the dark. This split voltage is given to pin 2 of IC 555. The variable resistor is set so that it crosses the potential of 1/3 in brightness and drops below 1/3 in the dark.
The sensitivity can be adjusted by this variable resistance. As soon as LDR becomes dim the voltage of pin 2 drops 1/3 of the supply voltage and pin 3 rises and the LED or buzzer that is connected to the output is activated.
![[Image: automatic%20street%20light.jpg?189db0]](http://circuiteasy.com/circuit_diagram/automatic%20street%20light.jpg?189db0)
Component used:
1. 9v battery with strip
2. Switch
3. L.D.R (Light dependent resistance)
4. I.C NE555 with Base
5. L.E.D (Light Emitting Diode) 3 to 6 pieces.
6. Variable Resistance of 47 KΩ
7. P.C.B (555 printed circuit board or Vero card.
COMPONENTS:
A) Battery: For 9v power supply we can use 6pcs dry cell or single battery 6F22 9v part.
B) Switch: Any general purpose switch can be used. The switch is used as a circuit breaker.
C) L.D.R: (Light dependent resistance)
It is a special type of resistance whose value depends on the brightness of the light that falls on it. It has a resistance of approximately 1mega ohm when it is in total darkness, but a resistance of only about 5k ohms when the brightness is illuminated. It responds to a large part of the spectrum of light.
D) L.E.D: (light emitting diode)
A diode is a component that only allows electricity to flow in one way. It can be thought of as a one-way street for electrons. Due to this feature, the diodes are used to transform or rectify the AC voltage into a DC voltage. The diodes have two connections, an anode and a cathode. The cathode is the end in the outline with the point of the triangle pointing toward a line. In other words, the triangle points toward that cathode. The anode is, of course, the opposite end. The current flows from the anode to the cathode.
Light emitting diodes, or LEDs, differ from normal diodes where when a voltage is applied, they emit light. This light can be red (more common), green, yellow, orange, blue (not very common) or infal. LEDs are used as indicators, transmitters, etc. Most likely, an LED never burns like a normal lamp and often requires less current. Because the LEDs act as regular diodes and will short-circuit if they are connected between + and -, a current limiting resistor is used to prevent the same thing. LEDs may or may not be drawn with the surrounding circle.
E) Variable resistance: (Potentiometer)
Resistors are one of the most common electronic components. A resistor is a device that limits or resists current. The current limiting capacitance or resistance is measured in ohms, represented by the Greek symbol Omega. Variable resistors (also called potentiometers or simply "pots") are resistors that have a variable resistance. You adjust the resistance by turning an axis. This axis moves a wiper through the actual resistance element. By changing the resistance amounts between the wiper connection and the connection or connections to the resistance element, you can change the resistance. You will often see the resistance of the resistors written with K (kilohms) after the numerical value. This means that there are many thousands of ohms. For example, 1K is 1000 ohms, 2K is 2000 ohms, 3.3K is 3300 ohms, and so on. You can also see the suffix M (mega ohms). This simply means millions. Resistors are also rated for their power handling capability. This is the amount of heat that the resistance can take before it is destroyed. Power capacity is measured in W (watts) Common powers for variables
Resistors are 1 / 8W, 1 / 4W, 1 / 2W and 1W. Anything of a higher voltage is known as a rheostat
F) PCB (Printed Circuit Board)
With the help of P.C.B it is easy to assemble the circuit with clean and neat end products. P.C.B is made of bakelite with glued surface with copper track layout. For each leg of the components, the hole is made.
The connecting pin is passed through the hole and welded.
WORKING:
When the light falls on the LDR, its resistance decreases resulting in an increase in voltage on pin 2 of the IC 555. IC 555 has a built-in comparator, which compares between the input voltage of pin2 and 1/3 of the Supply voltage. When the input falls below 1/3, the output is set to high, otherwise set low. So that in
Brightness, input voltage increases
Do not get positive voltage at the output of pin 3 to drive the relay or LED, also in low light conditions we get output to energize.
Precautions:
A) Use a sensitive LDR. You can test it by using a multimeter.
B) I.C should not overheat while soldering, excess heat can destroy it. For safety and easy to replace, it is suggested to use the I.C. When placing the pin I, no. 1 must be secured in the right hole.
C) The opposite polarity of the battery can destroy I.C so please check the polarity before turning the circuit ON. One must use the diode in series with the switch for safety since the diode allows current flowing in one direction only.
D) L.E.D shines in forward polarization only so incorrect polarity of L.E.D will not shine. The voltage set out from our project is 7.3 volts therefore 4 LEDs in series can be easily used with out resistance.
E) Each component must be welded clean and clean. We should check for dry welds.
F) LDR must be adjusted in such a way that it should not get light from the lamp itself.
It can be understood in the following video:
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