ORP sensor SEN0165

userHead Maximo80 2022-07-28 16:48:55 461 Views2 Replies

Hi Everybody,


I'm building my Pool controller using PH and ORP sensors to check water quality, I'm using ESP8266 with ESPHOME connected to Home assistant to monitor these sensors.


For PH sensor there is no problem but with ORP sensor I'm quite confused due to it doesn't get normal values.

In my case I've connected a multimeter to read Voltage values from df robot orp board, and it fits with analog value I have in ESP8266 so the reading is correct.


I have a very estrange readings in comparison with manual testers ( I use strip test and also liquid test ), In my case, I can see with manual tests that Free chlorine is low but ORP sensor read values of 874 mV.


I have an orp calibration solution that marks 256mV, when I put the probe inside this liquid solution the values were more or less 256 mV but when I put again the sensor with the swimming pool water  it cames back to more than 800 mV, I though it was due to a PH deviation but it reads in 7,3 so it is correct.


I attach here the readings during calibration and after several hours reading after. 

Could you indicate me what is happening? Is there a problem with the probe?




2023-02-02 11:25:07


Do you use the example code from Wiki?

orpValue=((30*(double)VOLTAGE*1000)-(75*avergearray(orpArray, ArrayLenth)*VOLTAGE*1000/1024))/75-OFFSET;

One line of code is needed to convert the analog value to orp according the circuit.

Also, could you please check your power supply? Power supply can significantly influence the result.

If those issue can't solve your problem, it could be an issue with the probe, you can contact Tech support via email: [email protected]


Hope it can help!


userHeadPic Tonny12138
2022-07-29 18:08:32

When I try to calibrate it with board button, without the probe conected it returns me -47 mV. It is quite estrange as well.


Please let me know what can i do.



userHeadPic Maximo80