From the course: Learning Arduino: Interfacing with Analog Devices

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LDR (light-dependent resistor) sensor

LDR (light-dependent resistor) sensor - Arduino Tutorial

From the course: Learning Arduino: Interfacing with Analog Devices

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LDR (light-dependent resistor) sensor

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- [Narrator] Some analog sensors output a change in resistance. Here are two common types you will run into. Thermistors, which change resistance due to the variation in temperature. And Photoresistors, which change resistance due to variation in light intensity. The problem with the resistance based sensors is that the Arduino analog interface cannot directly detect a change in resistance. A light dependent resistor or LDR, is a common light sensor. It is simply a resistor that changes resistance as the amount of light, that falls onto it, varies. And this is how an LRD looks. An LDR is made of a high resistance semi-conductor materials. The resistance decreases as the light intensity increases. In the dark an LDR can have a resistance as high as several megaohms. In a bright light it can have a resistance as low as a few hundred ohms. This is the schematic symbol for an LRD. Notice that the symbol is like a resistor but surrounded by a circle with a light incident upon it. Since the…

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