The Gravity: Lab Grade Analog pH Sensor Kit (SEN0161‑V2) is a high‑precision pH sensor designed for liquid analysis, accurately measuring acidity and alkalinity. Widely used in aquaponics, aquaculture, environmental monitoring, and water quality testing, this sensor provides reliable data for both hobbyists and professionals.
Compared to V1, the upgraded SEN0161‑V2 delivers improved accuracy and a smoother user experience. Its onboard voltage regulator supports a wide input range of 3.3V to 5.5V, ensuring compatibility with Arduino and other 3.3V/5V microcontrollers. The hardware‑filtered output signal minimizes noise and ensures stable, low‑jitter readings. With the included Arduino library, users benefit from two‑point calibration and automatic detection of standard buffer solutions (pH 4.0 and pH 7.0), making setup simple, reliable, and efficient.
This makes the Gravity SEN0161‑V2 pH Sensor Kit the ideal choice for IoT water quality monitoring, smart farming, and scientific research applications.
Projects
Project 1. Calibrating an Analog pH Sensor (with Linear Algebra)
Introduction: This video is an overview and tutorial for an analog pH sensor that's compatible with both Arduino and Raspberry Pi. It will also give a general overview of linear functions and interpolation. Plus it will show you how to write a custom code to use this sensor on an unsupported platform (Espruino).
Project 2. How to use DFRobot pH Meter module with an ESP32
Project 3. How to measure and indicate the pH of liquids with Arduino and LCD
Introduction: This video will show how to measure the pH of common liquids in our home in an easy and comfortable way perfect for monitoring the pH of fish, chemicals, etc.
Project 4. pH Sensor: Assembling, Coding, & Calibrating with Arduino | Smart Gardening
Introduction: This video talks about what pH sensors are, why use them for aquaponics system, and how to assemble, code, and calibrate the Gravity: Analog pH Sensor (Version 2).
Project 5. How to use pH meter V2 in ESP32 with new calibration
Introduction: This tutorial will teach you how to program with esp32 and how to do calibration with arduino IDE, how to use ph meter v2 in esp32 with new calibration.
Features
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Wide voltage input (3.3~5.5V), compatible with both 3.3V and 5V boards
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Low-jitter output signal thanks to hardware filtering
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Gravity interface and BNC connector for easy, plug-and-play setup
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Two-point calibration via software library with auto buffer recognition
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Uniform sensor size and connector for easier system integration
Applications
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Aquaponics and hydroponics systems
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Aquaculture water quality monitoring
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Laboratory chemical testing
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Environmental water sampling
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DIY multi-parameter water testing kits
Technical Specifications
Signal Conversion Board (Transmitter V2)
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Supply Voltage: 3.3~5.5V
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Output Voltage: 0~3.0V
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Probe Connector: BNC
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Signal Connector: PH2.0-3P
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Measurement Accuracy: ±0.1 @ 25℃
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Board Dimensions: 42mm × 32mm (1.66 × 1.26 in)
pH Probe (Lab Grade)
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Detection Range: 0 ~ 14 pH
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Zero Point: 7 ± 0.5
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Temperature Range: 5 ~ 60°C
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Response Time: < 2 minutes
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Internal Resistance: < 250MΩ
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Probe Life: > 0.5 years (depends on usage)
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Cable Length: 100cm
Package Contents
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1x Lab Grade pH Probe
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1x pH Signal Conversion Board (Transmitter V2)
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1x Gravity Analog Sensor Cable
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2x pH Standard Buffer Solution 4.0
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2x pH Standard Buffer Solution 7.0
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2x Waterproof Gasket
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1x Screw Cap for BNC Connector
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4x M3 × 10 Nylon Pillar
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8x M3 × 5 Screws
Important Notes
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Keep the BNC connector and signal board dry and clean to avoid measurement errors.
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Avoid placing the board on wet surfaces; use nylon pillars for mounting.
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The glass bulb at the probe tip is delicate — handle with care to prevent damage.
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Do not leave the probe connected to the board without power for long periods.
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Crystals forming around the protective cap are normal and do not affect accuracy. Return them to the cap if possible.
FAQ
How often does the pH probe need to be calibrated?
The calibration interval depends on the frequency of use. In general, calibration can be performed once a month. For frequent usage, it is recommended to calibrate the probe once a week. Always use fresh standard buffer solution during calibration to ensure accuracy.
Is two‑point calibration necessary, or can I perform only one‑point calibration?
For low‑demand applications, a single‑point calibration using a neutral buffer solution (pH 7.0) can be performed to confirm the zero point of the probe. In this case, the slope is assumed to be the theoretical value. However, to verify the actual slope, calibration with a pH 4.0 buffer solution should follow. Therefore, to achieve higher measurement accuracy, two‑point calibration is strongly recommended.