Project 2.5.2: Solar-Sensing Streetlight

Description	This project uses an LDR to detect ambient light levels and controls a Traffic Light Module to display Green (sunny), Yellow (dusk/dawn), or Red (night) based on the light intensity.
Use case	This project can be used in automation systems, interactive installations, and embedded control applications.

Components (Things You will need)

Building the circuit

Things Needed:

• Arduino Uno
• Arduino USB cable
• LDR module
• Traffic light module
• Jumper wires

Mounting the component on the breadboard and wiring the circuit.

Step 1: Place the LDR on the breadboard.

Step 2: Connect a jumper wire from VCC of the LDR to the Arduino 5V pin.

Step 3: Connect a jumper wire from D0 of the LDR to Digital pin 11 on the Arduino uno board using a jumper wire.

Step 4: Connect a jumper wire from GND(+) of the LDR to GND on the Arduino uno board using a jumper wire.

Step 5: Place the traffic light module on the breadboard and connect the GND pin of the module to an Arduino GND pin using a jumper wire.

Step 6: Connect the G (Green) pin to Digital Pin 3 on the Arduino uno board using a jumper wire.

Step 6: Connect the Y (Yellow) pin to Digital Pin 4 on the Arduino uno board using a jumper wire.

Step 6: Connect the R (Red) pin to Digital Pin 5 on the Arduino uno board using a jumper wire.

NB: Make sure all components are securely placed on the breadboard with correct orientation.

Make sure to connect the Arduino USB cable to the Arduino board.

PROGRAMMING

Step 1: Open your Arduino IDE. See how to set up here: Getting Started.

Step 2: Type the following code const int ldrPin = 11;, const int greenLED = 3;, const int yellowLED = 4;, const int redLED = 5; as shown in the image below.

Step 3: Type the following code Serial.begin(9600);, pinMode(ldrDigitalPin, INPUT);, pinMode(greenLED, OUTPUT);, pinMode(yellowLED, OUTPUT);, pinMode(redLED, OUTPUT); inside void setup() as shown in the image below.

Step 4: Type the following code int isDark = digitalRead(ldrDigitalPin);, if (isDark == HIGH), { Serial.println("Streetlight Status: NIGHT (Red On)");, digitalWrite(greenLED, LOW);, digitalWrite(yellowLED, LOW);, digitalWrite(redLED, HIGH); } inside void loop() as shown in the image below.

Step 5: Type the following code else { Serial.println("Streetlight Status: DAY (Green On)");, digitalWrite(greenLED, HIGH);, digitalWrite(yellowLED, LOW); , digitalWrite(redLED, LOW); } inside void loop() as shown in the image below.

Uploading the code

Step 1: Save your code. See the Getting Started section

Step 2: Select the Arduino board and port. See the Getting Started section

Step 3: Upload your code.

CONCLUSION

This project helps learners understand how to combine multiple components with Arduino to create more complex interactive systems and automation solutions.