Automatic Street Light
Science Project
Simpal LDR Circuit using IC 555 Timer: Automatic Street Light DIY by Manmohan Pal
Here we have explained a dark detector circuit by using 555 timer IC and a LDR (Light Dependent Resistor) which senses the light in surroundings and if it does not find the light, it triggers the IC and glows an LED attached with the circuit. In place of LED we can also use a buzzer or speaker to use it as dark detector alarm. The concept of this LDR circuit is quite simple and based on the working of LDR. So lets first understand more about LDRs.
Video link : LDR circuit using IC 555 Timer
https://www.youtube.com/watch?v=1gwUOnkJzxY
LDRs are a type resistors made from semiconductor materials to enable them to have their light sensitive properties. There are many types of LDRs but one of the most popular material used is cadmium sulphide (CdS). These LDRs or also known as photo resistors works on the principle of “Photo Conductivity”. Now what this principle says is , whenever light falls on the surface of the LDR (in this case) the conductance of the element increases or in other words the resistance of the LDR falls when the light falls on the surface of the LDR. This property of the decrease in resistance for the LDR is achieved because it is a property of semiconductor material used on the surface.
Here in this dark detecting LED circuit, LDR is configured with 555 timer IC in ASTABLE mode in such a way that 555 ASTABLE generates square wave when the light intensity goes below a certain level.
1. pin no 6 is connected to pin no 2
2. pin no 4 is connected to pin no 8
3. a resistor of 5 k is connected between pin no 1 and pin no 2
4. a LDR is placed between pin no 4 and pin no 2
5. LED is connected between pin no 1 and pin no 3
When there is dark on LDR the LEDs are ON i.e. at night lights will glow automatically
Where there is light on LDR the LEDs are off i.e. in day time lights are off automatically
above figure shows the circuit diagram of dark detecting LED. This circuit shows how we can convert a simple astable mode circuit to a “dark sensor”. We just need to add an LDR and a resistor in the circuit, then it simply works as dark detector. A general purpose LDR is used for sensing the light. When proper light is falling on the LDR its resistance is very low. When there is no light the LDR resistance increases. At this time the IC is triggered and glows the LED attached with the circuit
Manmohan Pal
Mob. 8989811397
Email- mannmohanpal@gmail.com
Youtube Channel: https://www.youtube.com/channel/UCDnhARnHOEIPuNIEp5vPdGQ
Automatic Street Light Circuit
Science Project
Simpal LDR Circuit using IC 555 Timer: Automatic Street Light DIY by Manmohan Pal
Here we have explained a dark detector circuit by using 555 timer IC and a LDR (Light Dependent Resistor) which senses the light in surroundings and if it does not find the light, it triggers the IC and glows an LED attached with the circuit. In place of LED we can also use a buzzer or speaker to use it as dark detector alarm. The concept of this LDR circuit is quite simple and based on the working of LDR. So lets first understand more about LDRs.
Video link : LDR circuit using IC 555 Timer
https://www.youtube.com/watch?v=1gwUOnkJzxY
LDRs are a type resistors made from semiconductor materials to enable them to have their light sensitive properties. There are many types of LDRs but one of the most popular material used is cadmium sulphide (CdS). These LDRs or also known as photo resistors works on the principle of “Photo Conductivity”. Now what this principle says is , whenever light falls on the surface of the LDR (in this case) the conductance of the element increases or in other words the resistance of the LDR falls when the light falls on the surface of the LDR. This property of the decrease in resistance for the LDR is achieved because it is a property of semiconductor material used on the surface.
Here in this dark detecting LED circuit, LDR is configured with 555 timer IC in ASTABLE mode in such a way that 555 ASTABLE generates square wave when the light intensity goes below a certain level.
1. pin no 6 is connected to pin no 2
2. pin no 4 is connected to pin no 8
3. a resistor of 5 k is connected between pin no 1 and pin no 2
4. a LDR is placed between pin no 4 and pin no 2
5. LED is connected between pin no 1 and pin no 3
When there is dark on LDR the LEDs are ON i.e. at night lights will glow automatically
Where there is light on LDR the LEDs are off i.e. in day time lights are off automatically
above figure shows the circuit diagram of dark detecting LED. This circuit shows how we can convert a simple astable mode circuit to a “dark sensor”. We just need to add an LDR and a resistor in the circuit, then it simply works as dark detector. A general purpose LDR is used for sensing the light. When proper light is falling on the LDR its resistance is very low. When there is no light the LDR resistance increases. At this time the IC is triggered and glows the LED attached with the circuit
Manmohan Pal
Mob. 8989811397
Email- mannmohanpal@gmail.com
Youtube Channel: https://www.youtube.com/channel/UCDnhARnHOEIPuNIEp5vPdGQ
Automatic Street Light Circuit
awesome explanation on dark detector using LDR and how can use
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