1. www.bluesquarething.co.uk/kthree/flowol.htm Flowol subroutines Subroutines are used to:  Simplify your code to make it easier to read (or for someone else to read)  Avoid having to write the same block of code a number of times  Break a bigger problem into smaller steps

2. www.bluesquarething.co.uk/kthree/flowol.htm Flowol subroutines Subroutines are smaller programs which run inside larger programs  Drag out a new START block  Make the block a SUB  Give the SUB a sensible name  Code the SUB  End with a STOP block

3. www.bluesquarething.co.uk/kthree/flowol.htm Flowol subroutines As the Big Wheel rotates the lights need to flash on and off. Sub flashLights Turn red on Delay 1 second Turn blue on Delay 1 second Turn yellow on Delay 1 second Turn lights off Delay 1 second Stop You should be able to make the lights do more interesting flashing patterns than this

4. www.bluesquarething.co.uk/kthree/flowol.htm Flowol subroutines Turning the wheel… Start Is Input 1 on? If Yes Run Sub flashLights Turn Motor A Forward Loop back to Start If No Turn Motor A off Loop back to start How could you turn the lights off once they start flashing?

5. www.bluesquarething.co.uk/kthree/flowol.htm Flowol subroutines Key vocabulary:  Subroutine  Efficiency  Loop  Condition  Pseudo Code