Activity 5: Make Decisions

Your BOE Shield-Bot will need to make a lot of navigation decisions based on sensor inputs.  Here is a simple sketch that demonstrates decision-making.  It compares the value of a to b, and sends a message to tell you whether or not a is greater than b, with an if…else statement. 

If the condition (a > b) is true, it executes the if statement’s code block: Serial.print("a is greater than b").  If a is not greater than b, it executes else code block instead: Serial.print("a is not greater than b"). 

  • Enter the code into the Arduino editor, save it, and upload it to the Arduino.
  • Open the Serial Monitor and test to make sure you got the right message.
  • Try swapping the values for a and b.
  • Re-upload the sketch and verify that it printed the other message.
// Robotics with the BOE Shield - SimpleDecisions

void setup()
{
  Serial.begin(9600);

  int a = 89;
  int b = 42;

  if(a > b)
  {
    Serial.print("a is greater than b");
  }
  else
  {
    Serial.print("a is not greater than b");
  }
}

void loop()
{
  // Empty, no repeating code.
}