Using the SP-2 TDS probes with Arduino

[stratosg]

Hello,

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:
https://www.freshwatersystems.com/p-1390-hm-digital-sp-2-dual-tds-sensor-probe-for-dm-1-dual-inline-tds-monitor.aspx?utm_source=Googlebase&utm_medium=Feed&utm_campaign=Product&utm_term=HM-SP-2&gclid=CjwKCAjw2rjcBRBuEiwAheKeL5PstaYw_OHHD0HHncSehLgXGDFtpXspxgADo_S-NJkQlnf0zuLXvBoCbBEQAvD_BwE

These are used by the very common meter:
https://www.ebay.com/itm/DM-1-Inline-Dual-TDS-Monitor-Online-RO-DI-Water-Filter-ppm-Meter-1-4-HM-Digital/392116280448

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!

[wvmarle]

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 :-)

[stratosg]

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).