Using the SP-2 TDS probes with Arduino


I have seen a few posts here regarding TDS but I wanted to see if anyone can guide me in getting TDS from the mentioned probes.

The probes are:

These are used by the very common meter:

These are very accurate and inexpensive meters but I would like to integrate the readings in a larger project. So, my thought is to buy the probes and somehow interface them with the Arduino.

Now, I know that TDS measurement is a complicated issue in of itself and that DM-1 meter is probably doing a lot of cool stuff, but seeing that the probes have 4 wires each (8 total for the dual) does anyone have any clue as to how these are interfaced properly?

Any hints or guidance will be of immense help!

Not easy to read indeed, you need to use an AC signal for that.

Really gotta get my kickstarter going now... until then, have a look at the driver in my github page. I'll also post the schematics and so there later. Really gotta get the campaign up and running first :slight_smile:

Thanks for the response! Yah that would be great, any schematics or tips on implementation would be a great start.

Have you seen the sensor from DFRobot? They're doing something similar to you I think (although they have analog out).


I am trying to use HM Digital SP-5 Single TDS Sensor Probes with 4 Pin Connector with Arduino. I am trying to make the TDS meter with this probe. But I am really confused how to connect it to Arduino.

Can anyone guide me with this?