97 lines
3.1 KiB
Rust
97 lines
3.1 KiB
Rust
extern crate i2cdev;
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extern crate i2cdev_bmp280;
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extern crate i2csensors;
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extern crate si7021;
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use i2cdev::linux::{LinuxI2CDevice, LinuxI2CError};
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use i2cdev_bmp280::*;
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use i2csensors::{Barometer, Hygrometer, Thermometer};
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use si7021::{Si7021, SI7021_I2C_ADDRESS};
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use std::env;
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static BMP280_I2C_ADDRESS: u16 = 0x76;
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fn main() -> Result<(), LinuxI2CError> {
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let mut verbose = false;
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let mut args = env::args().skip(1).peekable();
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if let None = args.peek() {
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eprintln!("Usage: tiny-wetter [-v] <i2c device> <altitude>");
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return Ok(());
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}
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if let Some(arg) = args.peek() {
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if arg == "-v" {
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verbose = true;
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args.next();
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}
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}
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let i2c_path = args.next().expect("missing i2c device");
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let altitude = args.next().expect("missing altitude").parse().expect("invalid altitude");
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let weather = read_tiny_wetter(&i2c_path)?;
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if verbose {
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println!("temperature (bmp280): {:6.1} °C", weather.temperature_bmp280);
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println!("temperature (si7021): {:6.1} °C", weather.temperature_si7021);
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println!("corrected temperature: {:6.1} °C", weather.temperature());
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println!("relative humidity: {:6.1} %", weather.relative_humidity);
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println!("real pressure: {:6.1} hPa", weather.pressure / 100.);
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println!("pressure at sea level: {:6.1} hPa", weather.sea_level_preassure(altitude) / 100.);
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} else {
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println!("{:.1} {:.1} {:.1}",
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weather.temperature(),
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weather.relative_humidity,
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weather.sea_level_preassure(altitude) / 100.,
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);
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}
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Ok(())
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}
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struct TinyWetterReading {
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temperature_bmp280: f32,
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temperature_si7021: f32,
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pressure: f32,
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relative_humidity: f32,
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}
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impl TinyWetterReading {
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fn temperature(&self) -> f32 {
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(self.temperature_bmp280 + self.temperature_si7021) / 2. - 1.5
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}
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fn sea_level_preassure(&self, altitude: f32) -> f32 {
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let coef = 13f32 / 2000.;
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let divisor = self.temperature() + coef * altitude + 273.15;
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self.pressure * (1f32 - coef * altitude / divisor).powf(-5.257)
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}
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}
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fn read_tiny_wetter(path: &str) -> Result<TinyWetterReading, LinuxI2CError> {
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let bmp280_settings = BMP280Settings {
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compensation: BMP280CompensationAlgorithm::Float,
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t_sb: BMP280Timing::ms4000,
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iir_filter_coeff: BMP280FilterCoefficient::UltraHigh,
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osrs_t: BMP280TemperatureOversampling::x16,
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osrs_p: BMP280PressureOversampling::UltraHighResolution,
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power_mode: BMP280PowerMode::ForcedMode,
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};
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let i2c_device = LinuxI2CDevice::new(path, BMP280_I2C_ADDRESS)?;
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let mut bmp280 = BMP280::new(i2c_device, bmp280_settings)?;
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let i2c_device = LinuxI2CDevice::new(path, SI7021_I2C_ADDRESS)?;
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let mut si7021 = Si7021::new(i2c_device);
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Ok(TinyWetterReading {
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temperature_bmp280: bmp280.temperature_celsius()?,
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temperature_si7021: si7021.temperature_celsius()?,
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pressure: bmp280.pressure_kpa()? * 1000.,
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relative_humidity: si7021.relative_humidity()?,
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})
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}
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