ORP is something you might want to monitor if you are using ozone or if you simply want to monitor the general health of your tank. The sensor generally has a small PCB which is mounted in the sensor module and a probe for the tank water.
The PH sensor is an Analog sensor and can only be conected to one of the Senosor module analog ports.
Here is how to set one up....
Recomended sensors...
Although the Marine assistant hardware will work with a wide range of sensors I recomend using a higher quality one, though my testing I found the results to be more consistant and reliable than using "cheap" sensors, for that reason I recomend the following:
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Atlas Scientific Surveyor™ ORP Kit
ORP Sensor
Analog sensor
An ORP (Oxidation-Reduction Potential) sensor measures the water's ability to break down contaminants, indicating overall water quality in a reef aquarium. It consists of a measuring electrode and a reference electrode that detect the voltage generated by redox reactions in the water. A higher ORP value means strong oxidation (better water quality), while a lower value indicates reducing conditions. ORP sensors help monitor the effectiveness of filtration, ozone systems, and overall tank health.
The ORP sensor needs to be connected to one of the analog ports in the sensor module, each port can supply either 5v or 3,3v to power the sensor. The 4 ports are labeled with their intended use, in this case use the ORP port. connect 5v (or3,3v), GND and Signal to thecoresponding pins.
The case has a removable section where you can mount the senosr pcb too. remove the 3d printed cover over the outlet to allow the BNC conector to leave the case.
Be sure to mount the Probe in an area of your sump that has good flow, 3d printed Probe holders are available in the Shop.
Hardware conection
How its conected
Software setup
Checking the Code
Analog sensors are actually quite simple to setup. The code has everything in place and if You use the ports as shown on the PCB then there is no need to change anything, simply uncomment the sensors you have conected, The most Important part here is to ensure your sensor is calibrated correctly. Here is a quick rundown on the part of the code that is used then a guide on how to calibrate.
The code:
Line for line:
107: Name of the platfom the code is using (The hardware)
108: What pin on the ADS1115 board we are using
109: Gain - used to set the voltage from the sensor. (More info in the link below)
110: Name Of the sensor
111: Filters currently used
112 - 115: Calibration data, explained in more detail below
117 - 120: Median used to smooth out the data and create a more consistant result.
121: Unit of measurement.
Calebration:
To calibrate the sensor in MA you will need an ORP calibration solution. Calibration is the same as the PH probe, only difference being there is only one value needed to be set. Place the probe in the solution then open the logs and write down the voltage reading, be sure to leave the Probe in for at least 2-3 minutes to get a good reading. Input these values into the code (Example above has 2,075v set for the 4v solution), be sure they are all uncommented and then reinstall the code.
More details on the ADS1115 and ESP can be found here:
Datasheet for the AtlasScientific ORP probe can be found here:
https://files.atlas-scientific.com/Surveyor-ORP-datasheet.pdf
Links
Here are a few links to where you can purchase your sensors, click the link depending on your location.
Worldwide link generally takes longer to be delivered but is a little cheaper. Better if you want to bulk order.
Full disclosure: some of these links are affiliate links, clicking them and purchasing though my links helps me support the project.