How to Eliminate Electrical Interference When Using Multiple Gravity Sensors (pH & EC) in One Tank?
dd_Growth 2026-10-08 16:11:54 15 Views1 Replies I am currently building an automatic water quality monitoring system for my hydroponic setup.
I am considering using multiple DFRobot gravity simulation sensors to track nutrient solution.
Will I encounter serious issues with electrical interference (crosstalk) or grounding circuits?
Sensors in the same tank: Gravity Analog pH Sensor V2 (SKU: SEN0161-V2) and an EC (SKU: DFR0300) or TDS Sensor (SKU: SEN0244).
1. Hardware Solution: Is there a Gravity-compatible Analog Signal Isolator module to cut off this water-based ground loop?
2. Software/Wiring Workaround: Can we power the sensors sequentially using GPIO/relays, and does anyone have sample code for this?
Thank you for your help!
hi，the nutrient solution is conductive, so any two probes in the same tank share a common electrical path through the water. That's your ground loop.
On your two ideas, the honest version:
Analog isolator: I wasn't able to find a ready-made "analog signal isolator" in DFRobot's standard Gravity line for this exact cut. The clean alternative is per-sensor isolated power: feed each board from its own small DC-DC isolator so the two boards don't share a return, and optionally buffer each analog output with a low-impedance op-amp follower before it reaches the ADC. That kills most of the crosstalk in practice.
Sequential powering - works for driver crosstalk, but be careful: toggling each sensor's VCC on and off with a MOSFET/relay (read one, disable it, then power the next) genuinely reduces drive crosstalk between the two boards. What it does NOT do is break the water loop - the probes themselves stay electrically connected through the liquid even when only one is powered. So use it as a first fix, not the fix.
Keep wires short and thick between each sensor and its power/ground star-point, and physically separate the two probes in the tank a few cm if layout allows.
Jason.Miao 