Physical Computing with Rust

With the help of the sleep function and a little loop, you can make the LED flash.

• Edit the examples/flash.rs file in an editor with the following code:

extern crate rust_gpiozero;
use rust_gpiozero::*;
use std::thread::sleep;
use std::time::Duration;

fn main() {

// Tell the Pi which GPIO pin you are using
let mut led = LED::new(17);

loop{
    // Make the led switch on
    led.on();

    // Let the LED stay on for one second
    sleep(Duration::from_secs(1));

    // Make the led switch off
    led.off();

    // Let the LED stay off for one second
    sleep(Duration::from_secs(1));
    }
}

• Run run flash example by running the following command:

cargo run --example flash

• The LED should be flashing on and off. To exit the program press Ctrl + C on your keyboard.

• In rust_gpiozero, an LED has a blink method which allows you to simplify the above code. The method takes two parameters, on_time and off_time. on_time is the number of second(s) the LED should stay on and off_time is the number of second(s) that the LED should stay off.

• Modify your code to the following:

extern crate rust_gpiozero;
use rust_gpiozero::*;

fn main() {

    // Tell the Pi which GPIO pin you are using
    let mut led = LED::new(17);

    // let the LED blink indefinitely, staying on for 1 sec and off for 1 sec    
    led.blink(1,1);
}

• Run the code. The LED should blink indefinitely, staying on for one second and off for one second. To exit the program press Ctrl + C on your keyboard.

• Try changing the parameters to blink to make it blink faster or slower.