markjb/tds_sensor

DFRobot Gravity TDS Sensor on ESP32 (FreeRTOS)

DFRobot Gravity TDS Sensor for ESP32

FreeRTOS task to read the DFRobot Gravity TDS sensor on an ESP32.

Mark Benson 2018 Licence - MIT or whatever is used for the rest of this project!

Compiles with the Espressif ESP-IDF.

The sensor is powered directly from an ESP32 GPIO pin as it only requires 3-6mA and the GPIOs can sink 12mA. Defaults to GPIO_NUM_32. The analog pin is connected to ADC1_CHANNEL_0 (GPIO_NUM_36).

What it does: Enables the sensor and waits 10 seconds for the reading to settle. Then takes a number of readings a few seconds apart and gives an average sample value. The sample value is then converted to a PPM value. The conversion includes some compensation values for the SAR ADC 11dB range. There is also a temperature compensation value that is currently static, but this should be measured to improve accuracy. Once the value is computed it is returned and the sensor is disabled until the next reading is needed.

The given TDS PPM value should be compared with a TDS meter and calibrated against a known sample.

TDS PPM conversion based on https://www.dfrobot.com/wiki/index.php/Gravity:_Analog_TDS_Sensor_/_Meter_For_Arduino_SKU:_SEN0244#More_Documents

tds_sensor's Issues

How to load it?

Hi,

How do you load this into ESPHome so I can use it?

Thanks

Reading TDS value upto 1000 PPM using ESP wroom 02 wifi module.

Hello,
I am currently working on ESP wroom 02 for TDS reading purpose. I have TDS sensor at TOUT(ADC pin) of esp wroom 02. I have been working with this code and modified for esp wroom 02 with range 0 to 520 ppm. I want to extend this range up-to 1000 ppm.
Upto now I did many changes to getting value up-to 1000 ppm but it could not work, with Vref and attenuation I achieved 950 PPM but the actual value of TDS is totally different. I have checked this with standard TDS meter ( MI company). I got too much difference in reading which were not I aspect, so would it be possible to extend this for 1000 ppm.

The following changes i did in Vref.
At Vref 1.18V we got upto 520PPM
At Verf 1.5V we got upto 720ppm -but we need 510ppm.
At vref 1.8V we got upto 950 ppm - but we need 710 ppm.

Please suggest me....

Regards,
Nilesh

TDSmeter_sensor_comparison_with_our_board.xlsx