Low-power design patterns in Embedded C - Mini Project: Build & Apply

Low-power design patterns

📖 Scenario: You are working on a small embedded device that needs to save battery power. To do this, you want to use low-power design patterns like putting the device to sleep and waking it up only when needed.

🎯 Goal: Build a simple embedded C program that sets up a low-power mode, configures a wake-up event, and then enters sleep mode. When the device wakes up, it should print a message.

📋 What You'll Learn

Create a variable to represent device state

Define a wake-up threshold variable

Use a function to check if the device should wake up

Print a message when the device wakes up

💡 Why This Matters

🌍 Real World

Embedded devices like sensors and wearables need to save battery by sleeping and waking only when necessary.

💼 Career

Understanding low-power design patterns is important for embedded systems engineers working on battery-powered devices.

1

DATA SETUP: Create device state variable

Create an integer variable called device_state and set it to 0 to represent the device being awake.

Embedded C

# Create an integer variable called device_state and set it to 0
# Your code here

Need a hint?

Use int device_state = 0; to create the variable.

2

CONFIGURATION: Define wake-up threshold

Create an integer variable called wake_up_threshold and set it to 5 to represent the condition to wake the device.

Embedded C

int device_state = 0;
// Create an integer variable called wake_up_threshold and set it to 5
# Your code here

Need a hint?

Use int wake_up_threshold = 5; to create the threshold variable.

3

CORE LOGIC: Check wake-up condition

Write a function called check_wake_up that takes an integer sensor_value and returns 1 if sensor_value is greater than or equal to wake_up_threshold, otherwise returns 0. Then, call this function with 7 and assign the result to device_state.

Embedded C

int device_state = 0;
int wake_up_threshold = 5;

// Write check_wake_up function and call it with 7, assign result to device_state
# Your code here

Need a hint?

Define the function with int check_wake_up(int sensor_value) and use an if-else to return 1 or 0.

4

OUTPUT: Print wake-up message

Write a printf statement that prints "Device awake!" if device_state is 1, otherwise print "Device sleeping.".

Embedded C

int device_state = 0;
int wake_up_threshold = 5;

int check_wake_up(int sensor_value) {
    if (sensor_value >= wake_up_threshold) {
        return 1;
    } else {
        return 0;
    }
}

device_state = check_wake_up(7);

// Print "Device awake!" if device_state is 1, else print "Device sleeping."
# Your code here

Need a hint?

Use if (device_state == 1) and printf("Device awake!\n").