auto intensity control of streetlights

Streetlights consume a large quantity of electrical energy daily to illuminate the streets. There are possibilities for intensity control for streetlights to reduce energy consumption. Auto intensity control of streetlights can be a good academic mini-project to implement the concepts that learned during the course.

Theory of light emitting diodes, pulse width modulation, microcontroller programming, etc. is necessary for doing the project.

Intensity control can be done in more than one way. We can explore two types of auto-intensity control of street lights.

Most of the street lights are now equipped with photo sensors to activate the light when sunlight goes off. Intensity control is not that common in street lights.

So you can try this after getting the information about the feasibility of the project. That means if it really provides you the economic gain or not. .


Let’s consider a street light that is an array of LEDs. White LEDs are being used as street lights due to their high efficiency. In addition to the efficiency, an LED provides the chance of dimming the light intensity.

A project can be done for auto intensity control of street lights. Illumination of the area covered by the street light can be maintained constantly controlling the intensity of street light. Low intensity is sufficient sometimes (low crowd time) in the region, which might be helpful to reduce energy consumption.

Solar-powered street light intensity control is important since they use energy stored in the battery. It’s always better to have less energy consumption in battery-powered systems.

Now let’s discuss two types of intensity control

#1 Intensity control of streetlights by turning LEDs off

The intensity of the street light reduces if some LEDs in the array are off. Light glows at maximum intensity when all the LEDs in the street light are on. A microcontroller controls the LEDs to be turned on and off after getting feedback on illumination using a light-dependent resistor.

The theory is simple – LDR detects the intensity of light and the microcontroller decides which LEDs should be on. If all LEDs are on intensity will be maximum and if all LEDs are off intensity will be minimum.

In the evening and morning, the intensity of street lights can be reduced to save energy.

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#2 Auto intensity control of streetlights using the PWM technique

Another method of intensity control of LED is using PWM signals. The intensity of all LEDs is controlled together using PWM. The intensity of the light decreases as the input to it reduces. Duty cycle control of the signal based on the input from optical feedback of LDR. 

Auto intensity control of street lights is a good electrical project which is based on the concepts of microcontroller programming. You can find your own method to implement the project. For example, the microcontroller to use, and the number of LEDs. LDR, required intensity, etc.


Street light intensity control is a good basic academic project. Two methods are used for auto intensity control of street lights – The light off technique and the PWM technique.

Both of the methods are challenging and the PWM method gives more opportunity for accurate illumination control. The project can be extended to office room illumination auto-control etc.


  • Intensity of street light can be controlled in two ways – Light off, and PWM method
  • Office illumination auto control would be an extension of the project
  • Solar-powered street light auto intensity control is another project