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Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

In order to get a meaningful reading from an LDR you need to convert the resistance into a voltage which the Arduino's ADC can read. The simplest method is to use a voltage divider: the junction between the LDR (photoresistor) and R1 is the node to connect your analog pin to get your readings, which will be a voltage that is a proportion of the supply voltage (5V) defined by the ratio of the two resistances.

The KY-018 module mentioned above, already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

   5V ----+
          |
          |
         +++
         | | LDR
         | |
         +++
          |
ANALOG ---+
          |
         +++
         | | R1
         | |
         +++
          |
          |
GND ------+

Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

In order to get a meaningful reading from an LDR you need to convert the resistance into a voltage which the Arduino's ADC can read. The simplest method is to use a voltage divider: the junction between the LDR (photoresistor) and R1 is the node to connect your analog pin to get your readings, which will be a voltage that is a proportion of the supply voltage (5V) defined by the ratio of the two resistances.

The KY-018 module mentioned above already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

^{simulate this circuit – Schematic created using CircuitLab}

Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

Since a photoresistor can become a short (very low resistance) under strong light you should never connect a photoresistor to your power rail (5V) and ground (GND) directly, but use it as a part of a voltage divider: the junction between the LDR (photoresistor) and R1 is the node to connect your analog pin to get your readings.

The KY-018 module mentioned above, already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

   5V ----+
          |
          |
         +++
         | | LDR
         | |
         +++
          |
ANALOG ---+
          |
         +++
         | | R1
         | |
         +++
          |
          |
GND ------+

Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

In order to get a meaningful reading from an LDR you need to convert the resistance into a voltage which the Arduino's ADC can read. The simplest method is to use a voltage divider: the junction between the LDR (photoresistor) and R1 is the node to connect your analog pin to get your readings, which will be a voltage that is a proportion of the supply voltage (5V) defined by the ratio of the two resistances.

The KY-018 module mentioned above, already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

   5V ----+
          |
          |
         +++
         | | LDR
         | |
         +++
          |
ANALOG ---+
          |
         +++
         | | R1
         | |
         +++
          |
          |
GND ------+

Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

Since a photoresistor can become a short (very low resistance) under strong light you should never connect a photoresistor to your power rail (5V) and ground (GND) directly, but use it as a part of a voltage divider: that will assure you'll never sink or source too much current from your Arduino and it also provide a nice node to connect your analog pin to get your readings.

The KY-018 module mentioned above, already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

   5V ----+
          |
          |
         +++
         | | LDR
         | |
         +++
          |
ANALOG ---+
          |
         +++
         | | R1
         | |
         +++
          |
          |
GND ------+

Number 23 in the list says photoresistor, corresponding to module KY-018 in your kit, which is what you called photocell (a photocell is another type of sensor to my knowledge). As the name states, a photoresistor is a device changing it's resistance depending on the amount of light it detects/receive.

A photoresistor usually looks like:

Since a photoresistor can become a short (very low resistance) under strong light you should never connect a photoresistor to your power rail (5V) and ground (GND) directly, but use it as a part of a voltage divider: the junction between the LDR (photoresistor) and R1 is the node to connect your analog pin to get your readings.

The KY-018 module mentioned above, already provides all the necessary and provides you 3 pins: 5V, ANALOG and GND.

   5V ----+
          |
          |
         +++
         | | LDR
         | |
         +++
          |
ANALOG ---+
          |
         +++
         | | R1
         | |
         +++
          |
          |
GND ------+