This crate provides a driver for the HC-SR04/HC-SR04P ultrasonic distance sensor on Raspberry Pi, using rppal to access Raspberry Pi's GPIO.
Usage examples can be found in the examples folder.
```rust use hc_sr04::{HcSr04, Unit};
// Initialize driver.
let mut ultrasonic = HcSr04::new(
24, // TRIGGER -> Gpio pin 24
23, // ECHO -> Gpio pin 23
Some(23_f32) // Ambient temperature (if None defaults to 20.0C)
).unwrap();
// Perform distance measurement, specifying measuring unit of return value. match ultrasonic.measure_distance(Unit::Meters).unwrap() { Some(dist) => println!("Distance: {.2}m", dist), None => println!("Object out of range"), } ```
Distance measurement can be calibrated at runtime using the HcSr04::calibrate
method that this library exposes, passing the current ambient temperature as
f32.
```rust use hc_sr04::{HcSr04, Unit};
// Initialize driver. let mut ultrasonic = HcSr04::new(24, 23, None).unwrap();
// Calibrate measurement with ambient temperature. ultrasonic.calibrate(23_f32);
// Perform distance measurement. match ultrasonic.measure_distance(Unit::Centimeters).unwrap() { Some(dist) => println!("Distance: {.1}cm", dist), None => println!("Object out of range"), } ```