Variables Challenge

Hardware

• Metro ESP32-S2 MCU
• Grove Base Shield Board
• Sensors: Grove Button, LED Socket

Grove Board

• Unplug the Metro board
• Align the Grove base shield ontop of the Metro board, and press gently

Note: The pin numbers on the Grove board are different from the ones of the Metro board. You need to use the numbers of the Metro board. A mapping table is provided on the Grove base shield page.

External Blinking LED

Plug an external LED to the Grove shield.

Write a program that makes an external LED blinks faster, i.e. minimize delay. Start with a delay of 1000, decrement by steps of 50, after reaching 0ms restart.

• Observation: Copy past of previous program. We have to change Pin Number in multiple places.
• Problem: Duplication. We need to change different instructions, which is error-prone.
• Find and implement a the solution to allow changing only 1 instruction of the program

Digital Input from Button

Write a program that reads the status of a button. When the button is pressed, the LED should be turned ON. Otherwise, the LED should be turned OFF.

Inverted Digital Input from Button

Write a program that does the opposite as the previous one. When the button is pressed, the LED is turned OFF. And when, the button is released, the the LED is turned ON.

Serial Communication

Write a program that repeatedly writes a greeting message on the serial port. Observe the result on the Arduino Serial Monitor

Count Down

Write a program that displays a count down on the serial port.

• The count down starts at 10
• The value is decremented and displayed every second
• When the value reaches 0, the program displays a greetings message
• Nothing is displayed after the greeting message

"Infinite" Counter

Write a program with a counter initially set to 0. At each loop: - Increment the counter - Display the counter value on the serial port

Observation: Open the Arduino Serial Monitor on your computer, and anlyse the output. What can you say? How can you Fix it?

Remembering Button State

Write a program with a boolean variable initially set to false. The LED ON when variable ledStatus is true. When ledStatus is false the LED turns OFF. Pressing the button flips the value of ledStatus. When it's true it become false. Conversely, when it's false a button press flips it to true.

Observation: What happens some times when you press a bit too fast or too slow?

Remembering Button State with Delay

Modify the previous program to introduce a delay upon button press.

Observation: What happens when the button is kept pressed?

Input Status vs Rising/Falling Edges

Modify the program to flip the variable only after 2 consecutive events: button press + button release.