Introduction
Nowadays street lights are turns on manually but if we make it automatically no human interface is required. When light intensity goes bellow threshold value, street light turns on automatically. Voltage across LDR increases when light intensity decreases. This signal sense by arduino and it takes decision accordingly and turns on street light.
Circuit Diagram
- Make the connection as shown in bellow figure
Fig3.Circuit diagram
- Pin A0 sensed the voltage across LDR and these value is store in some variable.
- This value is compare with threshold value when it great than it, Arduino make the pin no 7,8 high.
Project Working
- LDR changes the resistance according to light intensity hence voltage across LDR changes.
- This analog value is read at pin A0 of arduino.
- According to set threshold value it takes control decision.
Program Steps
- Read analog value of ldr at pin A0.
- If this value is great than 900 then turn on the light.
- Otherwise turn off the light.
