Determining day or night

Hello Iam kind of need to arduino everything is going smoothly just wanted to know what sensor could be used to determine wether if it is day or night

Do you mean just if it is dark or light? If so you can use an LDR (light dependent resistor) or any of several other sensors.


Hi, If you are in a cave and can not access outside environment at all, a Real Time Clock would be best..