SNS - Low Pressure Sensor

boards/stm32f767zi/src/bin/low_pressure_test.rs

@@ -0,0 +1,28 @@
+#![no_std]
+#![no_main]
+
+use core::panic::PanicInfo;
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::adc::{Adc, AdcChannel};
+use embassy_time::{Duration, Timer};
+use hyped_boards_stm32f767zi::io::Stm32f767ziAdc;
+use hyped_sensors::low_pressure::LowPressure;
+use {defmt_rtt as _, panic_probe as _};
+
+/// Test task that just continually reads pressure from low pressure sensor and prints value to console
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    let p = embassy_stm32::init(Default::default());
+    info!("Low pressure sensor");
+
+    let adc = Adc::new(p.ADC1);
+    let pin = p.PA3;
+
+    let mut low_pressure_sensor = LowPressure::new(Stm32f767ziAdc::new(adc, pin.degrade_adc()));
+
+    loop {
+        info!("{}", low_pressure_sensor.read_pressure());
+        Timer::after(Duration::from_millis(100)).await;
+    }
+}

lib/sensors/Cargo.toml

@@ -9,6 +9,7 @@ embassy-sync = { version = "0.6.0", features = ["defmt"], git = "https://github.
 hyped_core = { path = "../core" }
 hyped_i2c = { path = "../io/hyped_i2c" }
 hyped_gpio = { path = "../io/hyped_gpio" }
+hyped_adc = { path = "../io/hyped_adc" }
 defmt = "0.3"
 
 [dev-dependencies]

lib/sensors/src/lib.rs

@@ -1,6 +1,7 @@
 #![no_std]
 
 pub mod keyence;
+pub mod low_pressure;
 pub mod temperature;
 pub mod time_of_flight;
 

lib/sensors/src/low_pressure.rs

@@ -0,0 +1,41 @@
+use hyped_adc::HypedAdc;
+
+/// The low pressure sensor (LPS) (model: SPAN-P10R-G18F-PNLK-PNVBA-L1) is able to detect
+/// pressure in range from 0 to 10 bar. The sensor utilises the ADC protocol to get the
+/// pressure value.
+///
+/// Links to datasheets
+///     (https://www.festo.com/gb/en/a/download-document/datasheet/8134897)
+///     (https://www.festo.com/media/catalog/203714_documentation.pdf)
+pub struct LowPressure<T: HypedAdc> {
+    adc: T,
+}
+
+const MAX_PRESSURE: f32 = 10.0;
+const ADC_RESOLUTION: f32 = 4096.0;
+const GRADIENT_LOW: f32 = MAX_PRESSURE / ADC_RESOLUTION;
+
+impl<T: HypedAdc> LowPressure<T> {
+    /// Create new low pressure sensor instance
+    pub fn new(adc: T) -> LowPressure<T> {
+        LowPressure { adc }
+    }
+
+    /// Convert ADC reading to bar unit and return value to caller
+    /// The conversion rate is expressed as a linear function of:
+    ///     pressure = (conversion gradient) * (ADC reading) + (minimum pressure value)
+    ///     (y = mx + c0)
+    /// where conversion gradient is
+    ///     (maximum pressure value - minimum pressure value) / (4096).
+    /// 4096 is the maximum ADC reading value.
+    /// Since LPS has a minimum pressure of 0 bar, c0 is 0 and was did not need to be included in
+    /// the source code.
+    pub fn read_pressure(&mut self) -> f32 {
+        let adc_val = self.adc.read_value() as f32;
+
+        // convert to bar unit
+        let bar_pressure_val: f32 = adc_val * GRADIENT_LOW;
+
+        bar_pressure_val
+    }
+}