2 Exploring New Automatic Street Light Circuits for Effective Urban Illumination, or "Enlightening the Night"

 Exploring New Automatic Street Light Circuits for Effective Urban Illumination, or "Enlightening the Night"

In this essay, we'll go through two(2) practical yet straightforward automatic street light circuits that employ solar power and 220 V relays. All of the circuits shown here can be used to automatically turn on a lamp at night and turn it off during the day.

What is a Street Light Automation System?

A device that detects the ambient light level conditions and automatically turns on or off an associated lamp depending on the ambient light level is called an automatic street light system.

When it gets too dark in the evening and the light level drops below the device's detecting threshold, it switches on a connected lamp to light up the space.

On the other hand, at dawn, when ambient light rises above the device's detecting threshold, it turns OFF the associated bulb. Without any human involvement, the bulb switches automatically on and off at different times of day and night.

A photosensitive resistor, such as an LDR, or a photosensitive semiconductor, such as a photodiode or a phototransistor, are typically employed as the device's light sensor.

What benefits can automatic street lamp systems offer?

The following are the primary benefits of using an automatic street system:

By making sure the lamp is never left on during the day and is turned off when there is enough ambient light to illuminate the streets naturally, it helps conserve electricity.

By ensuring that no human interaction is necessary to manually turn the lamp ON or OFF, it conserves personnel.

Removing human dependence allows the system to operate more efficiently while also saving money and time.

Due to the device's electronic monitoring, it operates with extremely high and effective accuracy.

Can we construct this at home?

Yes, you can create a home-based, extremely effective circuit for an automatic street light. This circuit can be constructed by even a complete novice in the field of electronics using very commonplace parts like transistors, resistors, and a relay.

However, in order to make this circuit, a person must be familiar with all the fundamental concepts of electronics as well as how to properly solder electrical components.

(1)Using a single transistor, an automatic street light

The first circuit diagram below demonstrates how a relay, an LDR, a few resistors, and a single transistor may be used to create a passable autonomous street lamp.

Parts List

All resistors are 1/4 watt 5% CFR

R1 = 1K

P1 = 10K preset

LDR1 = Any standard LDR

C1 = 220uF/25V electrolytic Capacitor

C2 = 10uF/25V Electrolytic Capacitor

C3 = 1000uF/25V Electrolytic Capacitor

D1----D5 = 1N4007 Diodes

T1 = BC547 Transistor

TR1 = 0-12V/500mA or 1Amp Transformer

RL1 = 12V Relay 200 to 400 ohm coil resistance

LED Bulb = LED bulb 220V/120V, 100 watt or as per street light requirement.

The circuit's operation is straightforward. The LDR has a low resistance during the daytime when the ambient light is sufficiently high. This reduced resistance keeps the transistor base closer to the positive level, maintaining the required 0.6V for the transistor. As a result, the transistor is still turned ON.

The relay remains operational with its contacts in the N/O position while the transistor is switched to the ON state.

The lamp remains switched OFF since it is connected to the relay's N/C position.

Now, the ground potential on the transistor base is raised via the P1 and the biassing potential to the base is shut off when the ambient light starts to decrease in the evening and finally reaches a level where the resistance of the LDR increases sufficiently.

The transistor finally turns ON when this occurs. The transistor's collector activates when it is turned ON, deactivating the relay in the process. From its original N/O position to the N/C position, the relay contacts switch.

This enables the electricity to pass through the lamp, illuminating it.

The cycle is repeated the following morning when the ambient light level on the LDR rises, and it does so every day.

The capacitors at the transistor and relay's bases make sure that the relay contacts smoothly switch over during the twilight or trip points rather than chattering.

To control the amount of light the relay is switched ON and OFF at, either the potentiometer or the preset can be set accordingly.

Keep in mind that when installing the street light circuit, you must make sure that the light from the bulb does not hit the LDR because doing so will cause the relay and the lamp to rapidly oscillate.

How to Set up

Keep the preset wiper at the ground level.

Switch ON the power supply.

Illuminate the LDR or the premise with the required amount of light at which you want the relay changeover to happen.

Now slowly adjust the P1 preset until the relay just activates.

Seal the preset with quick-fix glue.

Your circuit is all set now.

Next, test the results by covering the LDR with an opaque shield, you will find the LED bulb switching ON instantly, and vice versa,

IC 555 is used.

Although the transistorised above is straightforward, its operation might not be very precise. This indicates that the ON/OFF switching of the relay may not take place precisely at the same times of dawn and dusk.

The second design shown below successfully resolves this problem by utilising the IC 555.

Parts List

R1 = 220K 1/4 watt resistor or 1M preset

R2 = 1M 1/4 watt resistor

R3 = 10K 1/4 watt resistor

R4 = 100K 1/4 watt resistor

LDR1 = any standard LDR

C1 = 220uF electrolytic capacitor

D1 = 1N4007 Diode

T1 = BC547 transistor

IC1 = 555 IC

RL1 = 12V relay 200 to 400 ohm coil resistance

LED Bulb = any 100 watt LED bulb or as per the street light requirement

12V SMPS = 1no for powering the circuit

This IC 555-based automatic street lamp circuit is exceptionally accurate since it is controlled by an internal op amp. It will flip the relay consistently every day, almost at the same light levels, during the entire year.

The IC 555 is just used as a comparator in this application rather than being employed in its traditional form.

The suggested potentiometer or a predetermined R1 can be used to set the trip point. If no exact adjustments are needed, R1 can be a fixed 220K resistor; otherwise, a 1M preset resistor can be used.

What it Does

The output pin#3 potential is high during the daytime when the LDR has enough light because the LDR resistance is low, keeping the pin#2 grounded.

As a result, the relay's contacts are held at N/C and it continues to be switched OFF. In turn, this results in the light bulb staying in the OFF position.

As night falls, the light on the LDR dims, increasing its resistance. Through R1, this results in the development of a positive potential on IC 555 pin#2. As a result, pin #3 becomes negative, turning on the relay. Now that the relay contacts have shifted, the bulb is turned on by the N/O.

In this circuit, the 555 IC functions as a comparator rather than an astable or monostable multivibrator. It's critical to comprehend how a 555 functions generally in order to comprehend this somewhat uncommon use: The output becomes high when input pin 2 receives a trigger (low pulse). A voltage that is less than one-third of the supply voltage is considered to be this low trigger pulse. The output returns to being low when the voltage at pin 6, the second input, briefly surpasses 2/3 of the supply level.

Since pin 6 is connected directly to the positive supply rail, the chip's output could still flip to the low state even though the second input pin 6 is not used in this configuration.

The level of hysteresis can be adjusted by connecting a resistor between pins 5 and 7 of the 555, as shown in the circuit diagram. Hysteresis level and resistor value are inversely connected, with study on 100K being a good place to start. R1 can be changed to a 1M potentiometer or preset to alter the responsiveness of the circuit.

The supply voltage of the circuit should, in theory, match the coil voltage of the relay. However, don't use more over 16 V or the 555 may get damaged. The circuit uses 4 mA of current, excluding the relay, at a supply voltage of 12 V. The relay is powered after a delay of about 2 seconds, which is ensured by the components R2 and C1, making the circuit impervious to abrupt changes in light intensity.

How to Construct

.With the aid of the following elements, the automatic street light circuit based on the IC 555 described above can be constructed:

Substitute a 1M preset for R1. Keep the wiper fully pointing in the positive direction.

Put a shield over the LDR that is opaque.

Next, turn on as much light as is necessary to illuminate the area where the relay changeover must occur.

Turn on the power and take the LED's cover off.

Now modify preset R1 so that the lamp just briefly turns off.

Your circuit is now prepared.

After that, try covering the LDR with your finger to see what happens. The bulb should be switched on immediately after the relay activates, and the lamp will be turned off when the finger is removed.

Conclusion:

Automatic street light circuits present an appealing alternative to achieve cities' goals of sustainability and efficiency. The presented circuits show how street lighting technology has advanced, from simple photocell control to complex IoT-enabled systems. Municipalities may improve safety and visibility while also advancing the more general objectives of energy conservation and smart city development by putting these intelligent ideas into practise.