DFRobot - Gravity: Analog TDS Sensor/ Meter for Arduino

This Gravity analog TDS sensor turns an Arduino project into a DIY meter for tracking total dissolved solids in water. With a 0–1000ppm measurement range, this TDS sensor supports water sample comparisons, domestic water monitoring, and hydroponic experiments. The kit brings together a signal transmitter board, waterproof probe, and analog sensor cable, with Arduino wiring instructions and example code available in the Product Wiki. From a simple serial-monitor readout to a custom water monitoring project, this TDS sensor provides an accessible way to add TDS measurements to a microcontroller-based design.

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Easy Arduino Setup, from Wiring to Calibrated Readings

This analog TDS sensor connects through the included 3Pin cable without soldering, simplifying assembly for DIY projects. A 3.3–5.5V supply range and 0–2.3V analog output support both 3.3V and 5V controllers with suitable analog inputs. Arduino examples cover basic measurements and calibration with a known reference solution, providing a clear starting point for displaying TDS values in ppm before adding project-specific displays, logging, or control functions.

AC Excitation for Stable Water Monitoring

This TDS sensor uses AC excitation to help prevent probe polarization, supporting a more stable output signal and extending probe service life. This design is useful for projects that take repeated water measurements, such as tracking TDS changes over time or comparing samples during an experiment. The Arduino measurement example also applies median filtering to sampled readings, helping reduce fluctuations in the displayed value.

Waterproof Probe for In-Water Measurements

This TDS sensor includes a two-electrode probe with a waterproof head and cable, allowing the sensing end to remain immersed during water measurements. The separate probe and signal board make placement straightforward: the probe sits in the water while the electronics remain outside the container. The 83cm total probe length provides flexibility when arranging a tabletop test, educational demonstration, or DIY water monitoring setup.

• 0–1000ppm TDS measurement range for water monitoring projects
• 3.3–5.5V input and 0–2.3V analog output for suitable 3.3V and 5V controllers
• AC excitation helps reduce probe polarization and supports output stability
• Waterproof probe head and cable for immersed measurements; connector and board must remain dry
• Included analog sensor cable for connection without soldering
• Arduino measurement and calibration examples with software temperature compensation using a separate temperature measurement

• DIY domestic water TDS trend monitoring
• Hydroponic solution TDS experiments within 0–1000ppm
• Educational demonstrations of conductivity-based TDS estimation
• Arduino water sample comparison and data logging projects

Signal Transmitter Board

• Input Voltage: 3.3 ~ 5.5V
• Output Voltage: 0 ~ 2.3V
• Working Current: 3 ~ 6mA
• TDS Measurement Range: 0 ~ 1000ppm
• TDS Measurement Accuracy: ± 10% F.S. (25 ℃)
• Module Size: 42 * 32mm
• Module Interface: PH2.0-3P
• Electrode Interface: XH2.54-2P

TDS probe

• Number of Needles: 2
• Total Length: 83cm
• Connection Interface: XH2.54-2P
• Color: Black
• Other: Waterproof Probe

Usage Precautions

• The probe must not be used in water above 55 degrees centigrade.
• The probe must not be placed too close to the edge of the container, otherwise readings may be affected.
• The probe head and cable are waterproof; the connector and signal transmitter board are not waterproof.

• Analog TDS Meter for Arduino x1
• Waterproof TDS Probe x1
• 3Pin Analog Sensor Cable x1