Functions Challenge

Hardware

Count Down Resettable via Button

Write a program, easy to read and evolve, that does the following.

  • Start by displaying a "Ready" message on the serial port.
  • Wait until the button is pressed
  • When the button is pressed, start the count-down described as following:
    • The count down start at 10
    • The value is decremented and displayed every second
    • When the value reaches 0, the program displays a "Ready"
    • Nothing is displayed after the greeting message
  • If the button is pressed again after the ready message, the count down restarts
  • The button is inactive during count-down. If is pressed during the count down, nothing happens.

Count Down Resettable via Serial Communication

Modify the previous proram to use Serial communication instead of the button press to rest the count down. When the string "go" is sent via the Serial monitor, the count down starts.

Hints:

  • Read from Serial port using readStringUntil(char) function
  • The input we provide on the serial port ends with a new line if we press enter. This is the character '\n'.
  • Alternatively, you can use trim() that removes spaces and new line characters.

Write a function named blink that takes 2 parameters :

  • pin number
  • milliseconds delay between state changes

Use the function in a program with 2 LEDs:

  • The onboard LED should blink every x milliseconds where x is defined by the value of potentiometer
  • The external LED on socket should blink every 2 * x milliseconds

Fade function

Write a function named fade that takes 1 parameter : pin number. It makes and LED fade in 5 steps. Steps duration is defined by the potentiometer. The maximum value is 500 milliseconds. The minimum value is 30 milliseconds.

Use the function in a program with 2 LEDs:

  • The onboard LED.
  • The external LED.

Hint:

Alternating Blink and Fade

Write a program that reuses the previous functions blink and fade.

  • Initially,
    • the onboard LED should blink
    • the LED on socket should fade
  • When the button is pressed:
    • the onboard LED should fade
    • the LED on socket should blink
  • Another button press will make us go back to the initial state

Delay vs Blinking Durations

Change the previous programs to ensure that the blinking durations are correct.

Hint