tds-meter-rs

An embedded-hal driver for TDS Meter (total disolved solids sensor)

Device

Links:

• product page
• manual

Also available under different brands (look for "water conductivity sensor" on ebay/amazon).

Example

```rs

![no_std]

![no_main]

use bsp::entry; use defmt::*; use defmtrtt as _; use panicprobe as ; use tdsmeter::TdsMeter;

use rp_pico as bsp;

use bsp::hal::{ adc::Adc, clocks::{initclocksand_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);

// External high-speed crystal on the pico board is 12Mhz
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();
// pico has 12-bit ADC and has 3.3V reference voltage
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 |