In order to accomplish this, [Bas] is using a light-dependent resistor and a pull-up resistor to create a resistance bridge, which is then connected to an analog input pin on a Raspberry Pi Pico.

The resistors in a potential divider can have fixed values, or one may be a variable component like an LDR (light dependent resistor) or a thermistor. These variable resistors allow the output ...

Many circuits published earlier have a serious drawback that only one light dependent resistor (LDR) is used for shadow detection. Described here is a simple but improved circuit of a smart shadow ...