pH Sensor with Analog Output for Arduino and Raspberry Pi

Specifications:

• Operating Voltage: 5V DC
• Operating Current: 5mA – 10mA (typical)
• Measurement Range: pH 0.00 – 14.00
• Measurement Accuracy: ±0.1 pH (at 25°C)
• Response Time: < 1 minute
• Output Type: Analog Voltage Signal
• Electrode Connector Type: Standard Industrial BNC
• Probe Cable Length: 1 meter [Estimated]
• Calibration: Onboard multi-turn potentiometer for offset adjustment
• Signal Board Dimensions: 42mm × 32mm × 20mm [Estimated]
• Weight: 0.075 kg [Estimated]
• Operating Temperature: 0°C to 60°C
• Compatible Platforms: Arduino, Raspberry Pi (requires external I2C ADC like ADS1115), ESP32/STM32 (requires voltage division for 5V analog output) 

Unlock New Capabilities

• Past Projects (Prerequisites): If you've already experimented with basic soil moisture sensors for potted plants or used simple float switches to monitor water levels, you already understand how to read analog sensor data — which means you're perfectly ready to upgrade from simply knowing if there is water, to knowing the chemical quality of that water.
• Feature Upgrade (What This Unlocks): This Analog pH Sensor Module unlocks precise automated dosing for hydroponic nutrient reservoirs, real-time water quality monitoring for sensitive aquarium setups, automated pool chemical dispensers, and DIY laboratory titration experiments. These are advanced environmental control projects you simply cannot build without accurate, continuous pH data.
• Effort Level & Minimum Hardware
  
  Effort Level: Intermediate

Minimum hardware to get started:

• Arduino Uno or similar 5V microcontroller — required to read the 0-5V analog output signal directly and process the pH value.
• BNC pH Electrode Probe (Included) — required to actually interface with the liquid and send the raw millivolt signal to the amplifier board.
• pH Calibration Buffer Solutions (e.g., pH 4.01, 6.86, 9.18) — required to calibrate the sensor's software offset before first use to ensure accurate readings.
• 3× Jumper Wires — required to connect the VCC, GND, and Analog Out pins from the sensor board to your microcontroller.

Included in the Box:

• 1× Signal Conditioning Sensor Board
• 1× E-201-C BNC pH Electrode Probe

Frequently Asked Questions

• Is this pH sensor module compatible with Arduino Uno?
  Yes, the analog output connects directly to any Arduino analog input pin (like A0) without requiring extra components.
• Can I use this liquid pH sensor with a Raspberry Pi?
  Yes, but since the Raspberry Pi lacks native analog inputs, you must wire the sensor through an external I2C ADC module like the ADS1115.
• Does this module work with 3.3V boards like the ESP32?
  Yes, but you must step down the 5V analog output signal using a voltage divider to prevent damage to the ESP32's 3.3V GPIO pins.
• Can I leave the pH probe submerged in my aquarium permanently?
  While possible, standard laboratory glass electrodes degrade much faster under continuous submersion; they are best used for periodic spot-checking or need frequent recalibration.
• What is the required operating voltage for the signal board?
  The signal conditioning board requires a stable 5V DC supply for the internal LM358 amplifier to scale the output accurately.
• Can I power this sensor board using a 3.3V supply?
  No, powering the board at 3.3V will cause the amplifier circuit to behave unpredictably and skew your pH readings.
• How much current does this module consume?
  The module is highly power-efficient, drawing only about 5mA to 10mA during active measurement.
• What do the pins on the sensor board do?
  V+ connects to 5V power, G- connects to Ground, P0 provides the analog voltage output, and T0 is an optional temperature pin (often unused).
• How do I connect the glass probe to the circuit board?
  Simply push the probe's metal BNC connector onto the board's BNC socket and twist a quarter-turn clockwise to lock it in place.
• Do I need pull-up resistors for the analog signal?
  No, the analog output line (P0) is directly driven by the onboard operational amplifier and requires no external pull-up resistors.
• Do I need a specific Arduino library to read the pH?
  No specialized library is required; you simply use the standard analogRead() function and map the resulting voltage to a pH scale in your code.
• How do I calibrate the pH readings in software?
  Submerge the probe in a known buffer solution (like pH 7.0), observe the raw voltage reading, and enter that value as your neutral offset in your code.
• Is example code available for MicroPython users?
  Yes, standard MicroPython machine.ADC scripts easily read the module's voltage output for calculation on ESP32 or Pico boards.
• Why is my Arduino displaying a constant, unchanging pH value?
  Ensure you have a common ground connection between the sensor board and your microcontroller, and verify the BNC connector is twisted fully into the locked position.
• Why are my pH readings drifting over the course of a few days?
  All glass pH electrodes experience natural drift and require periodic rinsing with distilled water and recalibration using standard buffer solutions.