Video
Circuit Diagram
Source Code
1int value;
2
3void setup() {
4 Serial.begin(9600);
5}
6
7void loop() {
8 value = analogRead(A0);
9 Serial.print("Value: ");
10 Serial.println(value);
11 delay(500);
12}FAQ
How does LDR work?▾
As the amount of light falling on the LDR (light-dependent resistor) increases, its resistance decreases. When a voltage divider is created using a 10 kΩ resistor, changes in light are converted into changes in voltage and can be read as a value between 0 and 1023 using `analogRead`.
What should the readings be in light and dark conditions?▾
It depends on the connection type; generally, high values are observed in bright conditions and low values in dark conditions (or vice versa). Note the bright and dark values in its natural environment using the Serial Monitor; these will be used to select threshold values in future projects.
I'm seeing garbled characters in the Serial Monitor. Why is that?▾
The baud rate in the Serial Monitor must match the value specified in the `Serial.begin()` function in the code (e.g., 9600). If they differ, garbled characters will appear on the screen.
Is there a more sensitive light sensor than an LDR?▾
Yes, I2C light sensors like the BH1750 measure light directly in lux (lx) and are much more consistent than LDRs. An LDR is sufficient for simple night lights and darkness detection.