tds-meter-rs
An embedded-hal driver for TDS Meter (total disolved solids sensor)
Device
Links:
Also available under different brands (look for "water conductivity sensor" on ebay/amazon).
Example
#![no_std]
#![no_main]
use bsp::entry;
use defmt::*;
use defmt_rtt as _;
use panic_probe as _;
use tds_meter::TdsMeter;
use rp_pico as bsp;
use bsp::hal::{
adc::Adc,
clocks::{init_clocks_and_plls, Clock},
pac,
sio::Sio,
watchdog::Watchdog,
};
#[entry]
fn main() -> ! {
let mut pac = pac::Peripherals::take().unwrap();
let core = pac::CorePeripherals::take().unwrap();
let mut watchdog = Watchdog::new(pac.WATCHDOG);
let sio = Sio::new(pac.SIO);
let external_xtal_freq_hz = 12_000_000u32;
let clocks = init_clocks_and_plls(
external_xtal_freq_hz,
pac.XOSC,
pac.CLOCKS,
pac.PLL_SYS,
pac.PLL_USB,
&mut pac.RESETS,
&mut watchdog,
)
.ok()
.unwrap();
let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
let pins = bsp::Pins::new(
pac.IO_BANK0,
pac.PADS_BANK0,
sio.gpio_bank0,
&mut pac.RESETS,
);
let adc = Adc::new(pac.ADC, &mut pac.RESETS);
let adc_pin_0 = pins.gpio28.into_floating_input();
let mut tds: TdsMeter<_, _, u16, _, _> = TdsMeter::new(adc, 4096, 3.3, adc_pin_0);
loop {
match tds.measure(25., &mut delay) {
Ok(tds_value) => info!("tds: {} ppm", tds_value),
Err(_) => error!("error occurred"),
}
delay.delay_ms(1000);
}
}
Results
Using pi pico:
Water |
PPM |
none/dry |
<4.5 |
de-ionised |
5 |
rain |
11 |
hard tap water |
310 |
saline |
1290 |