Fixed resistive divider and thermistor functions

Cargo.toml

@@ -16,7 +16,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.4.5"
+version = "0.4.6"
 edition = "2021"
 repository = "https://git.bfpower.io/BFPOWER/physical"
 readme = "README.md"

src/circuit/resistive_divider.rs

@@ -1,4 +1,4 @@
-use crate::quantity::{Ohms, Quantity, Volts};
+use crate::quantity::{Ohms, Volts};
 
 /// Given the resistance of the second resistor in a resistive voltage divider, calculate the resistance of the first resistor.
 pub fn solve_r1(
@@ -6,7 +6,7 @@ pub fn solve_r1(
     voltage_read: Volts<f32>,
     r2: Ohms<f32>,
 ) -> Ohms<f32> {
-    Ohms(r2.value() * (voltage_src.value() / voltage_read.value() - 1.0))
+    Ohms(r2.0 * (voltage_src.0 / voltage_read.0 - 1.0))
 }
 
 /// Given the resistance of the first resistor in a resistive voltage divider, calculate the resistance of the second resistor.
@@ -15,5 +15,29 @@ pub fn solve_r2(
     voltage_read: Volts<f32>,
     r1: Ohms<f32>,
 ) -> Ohms<f32> {
-    Ohms(r1.value() * (1.0  / (voltage_src.value() / voltage_read.value()) - 1.0))
+    Ohms((r1.0 * voltage_read.0) / (voltage_src.0 - voltage_read.0))
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Tests ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+#[cfg(test)]
+mod tests {
+    use crate::quantity::{OhmsVal, VoltsVal};
+    use super::*;
+    use float_cmp::assert_approx_eq;
+
+    #[test]
+    fn solve_r1_test() {
+        let resistance = solve_r1(3.3.volts(), 2.0.volts(), 1_000.0.ohms());
+
+        assert_approx_eq!(f32, 650.0, resistance.0);
+    }
+
+    #[test]
+    fn solve_r2_test() {
+        let resistance = solve_r2(3.3.volts(), 2.0.volts(), 1_000.0.ohms());
+
+        assert_approx_eq!(f32, 1538.462, resistance.0);
+    }
 }

src/transducer/part/thermistor.rs

@@ -1,5 +1,5 @@
-use libm::{log, logf};
 use crate::quantity::{Kelvins, Ohms};
+use libm::{log, logf};
 
 /// Convert thermistor resistance to a temperature using beta parameter equation
 pub fn convert_beta(
@@ -8,18 +8,31 @@ pub fn convert_beta(
     reference_temp: Kelvins<f32>,
     reference_resist: Ohms<f32>,
 ) -> Kelvins<f32> {
-    let kelvins = 1.0 / ((1.0 / reference_temp.0) + (1.0 / beta) * logf(resistance.0 / reference_resist.0));
+    let kelvins = 1.0 / ((logf(resistance.0 / reference_resist.0) / beta) + 1.0 / reference_temp.0);
     Kelvins(kelvins)
 }
 
 /// Convert thermistor resistance to a temperature using Steinhart-Hart equation
-pub fn convert_steinhart(
+pub fn convert_steinhart(resistance: Ohms<f64>, a: f64, b: f64, c: f64) -> Kelvins<f32> {
-    resistance: Ohms<f64>,
-    a: f64,
-    b: f64,
-    c: f64,
-) -> Kelvins<f32> {
     let log_omhs = log(resistance.0);
     let kelvins = 1.0 / (a + b * log_omhs + c * log_omhs * log_omhs * log_omhs);
     Kelvins(kelvins as f32)
 }
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Tests ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+#[cfg(test)]
+mod tests {
+    use float_cmp::assert_approx_eq;
+
+    use crate::quantity::{OhmsVal, KelvinsVal};
+    use super::*;
+
+    #[test]
+    fn convert_beta_test() {
+        let temperature = convert_beta(1538.462.ohms(), 3950.0, 298.15.kelvins(), 100_000.0.ohms());
+
+        assert_approx_eq!(f32, 435.31073, temperature.0);
+    }
+}