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Fixed resistive divider and thermistor functions

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This commit is contained in:
Zachary Sunforge
2025-02-12 21:41:01 -08:00
parent 41b767d8b5
commit 3de1787bf8
3 changed files with 49 additions and 12 deletions
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2
Cargo.toml
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@ -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"

30
src/circuit/resistive_divider.rs
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@ -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);
}
}

29
src/transducer/part/thermistor.rs
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@ -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(
resistance: Ohms<f64>,
a: f64,
b: f64,
c: f64,
) -> Kelvins<f32> {
pub fn convert_steinhart(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);
}
}