Assignment 1 (due 1/28)

You will need the following components:

• • 2 x photoresistor

  • 2 x 10k ohm resistor

  • 3 x LEDs (pick the same color)

  • 1 x 200 ohm resistor

  • 1 x Arduino Uno

  • 1 x breadboard

  • jumper wires

Software requirements

Your Arduino sketch must have

• • the following variables:

    • lightDifferenceThreshold 

      • two light readings that differ by less than this value are considered the same

      • use what you learned in Step 2 to pick a value 

    • 3 booleans (leftBrighter, sameBrightness, rightBrighter) to track the status for

      • if there is more light from the left photoresistor

      • if the two photoresistors are reading the same light (within the threshold)

      • if there is more light from the right photoresistor

    • 3 (digital) pin assignments for

      • an LED that lights if there is more light from the left 

      • an LED that lights if there is the same light from both

      • an LED that lights if there is more light from the right

    • 2 (analog) pin assignments for

      • a left photoresistor reading

      • a right photoresistor reading

    • 2 values to store

      • the value read from the left photoresistor

      • the value read from the right photoresistor

    • hint: you may wish to refer to the Arduino language reference (API) to determine the type for these variables

  • the following methods

  • setup

    • initialize Serial monitor

    • initialize status variables to false

    • assign LED pins as OUTPUT

    • assign photoresistor pins as INPUT

  • loop

    • • determine light readings and update status variables

      • update the output LEDs

      • wait 500 ms 

  • determineLightAndUpdateStatus

    • • read the light values from both photoresistors

      • print values

      • hint: you may wish to use Serial.print and Serial.println to get values on one line; only Serial.println will end with a newline

      • compute the difference between the two values

      • compare (using the threshold) to update the status variables appropriately

  • updateOutput

    • • based on the status variables, light the LEDs appropriately

  • lightLED

    • • you may wish to copy this function from the distance sensor example as a helper function

Step 3

Create a new page on your google site called Assignment 1: photoresistor that 

• lists the required components

• contains a short video (using a smartphone or lab computer -- you can use PhotoBooth to create a video) of your project in action

Submit your final Arduino sketch (.ino) on moodle. Do not post it on your google site!