As mentioned earlier, the Raspberry Pi is unable to read analog values. We are going to add the resistor using a RC circuit, as explained earlier. Here, we need the LDR, capacitor, and a 4.7 Kohm fixed resistor. The fixed resistor is used to make sure that when the LDR is completely saturated, which means that there is no resistance anymore, we won't fry our Raspberry Pi. An extra thing we need to keep in mind is that the Raspberry Pi is a 3.3V device. This means that in this schema, we will be using the 3.3V output because we will be reading the input on the Raspberry Pi pin, which cannot be higher than 3.3V.
Here is an image that shows how to attach this RC circuit to the Raspberry Pi:
Shut down the Raspberry Pi and disconnect the power. Let's first take a quick look at the capacitor. The one we are using is an electrolytic capacitor, which has a positive...