Create Variables

Create variable:

value

This stores the LDR sensor reading.

When Arduino starts up

forever

    set value to analog read pin A0

    if value < 200 then

        set digital pin 9 LOW
        set digital pin 10 LOW
        set digital pin 11 LOW

    else if value < 400 then

        set digital pin 9 LOW
        set digital pin 10 LOW
        set digital pin 11 LOW

    else if value < 700 then

        set digital pin 9 HIGH
        set digital pin 10 HIGH
        set digital pin 11 LOW

    else

        set digital pin 9 HIGH
        set digital pin 10 LOW
        set digital pin 11 LOW