• 3.3~5.5V wide voltage input
• Hardware filtered output signal, low jitter
• Gravity connector and BNC connector, plug-and-play, no soldering required
• Software library supports two-point calibration and automatically identifies standard buffer solution
• Uniform size and connector, convenient for the design of mechanical structures
• Industrial Probe - Support 7*24 Measurement
• Upgraded Transmitter - More Accurate and Stable
• SPECIFICATION
• Signal Conversion Board (Transmitter) V2
•  
• Supply Voltage: 3.3~5.5V
• Output Voltage: 0~3.0V
• Probe Connector: BNC
• Signal Connector: PH2.0-3P
• Measurement Accuracy: ±0.1@25℃
• Dimension: 42mm*32mm/1.66*1.26in

• Probe Type: Industrial Grade
• Detection Range: 0~14
• Temperature Range: 0~60°C
• Accuracy : ± 0.1pH (25 ℃) 
• Response Time: <1min
• Probe Life: 7*24hours >0.5 years (depending on the water quality)
• Cable Length: 500cm

Calibration

To ensure accuracy, the probe needs to be calibrated for its first use and after not being used for an extended period of time (once a month ideally). This tutorial uses two-point calibration and therefore requires two standard buffer solutions of 4.0 and 7.0. The following steps show how to operate two-point calibration.

• 1.Upload the sample code to the Arduino board, then open the serial monitor, after you can see the temperature and pH. If you added a temperature sensor, be sure to write the corresponding function and call it.

• 2.Wash the probe with distilled water, then absorb the residual water-drops with paper. Insert the pH probe into the standard buffer solution of 7.0, stir gently, until the values are stable.

• 3.After the values are stable, the first point can be calibrated. Specific steps are as follows:

  • 1. Input ENTER command in the serial monitor to enter the calibration mode.

• 2.Input CAL commands in the serial monitor to start the calibration. The program will automatically identify which of the two standard buffer solutions is present: either 4.0 and 7.0. In this step, the standard buffer solution of 7.0 will be identified.

• 3. After the calibration, input EXIT command in the serial monitor to save the relevant parameters and exit the calibration mode. Note: Only after inputing EXIT command in the serial monitor can the relevant parameters be saved.

• 4.After the above steps, the first point calibration is completed. The second point calibration will be performed below.

  • 4. Wash the probe with distilled water, then absorb the residual water-drops with paper. Insert the pH probe into the standard buffer solution of 4.0, stir gently, until the values are stable.

  • 5.After the values are stable, the second point can be calibrated. These steps are the same as the first calibration step. The specific steps are as follows:

• 1. Input ENTER command in the serial monitor to enter the calibration mode.

• 2.Input CAL commands in the serial monitor to start the calibration. The program will automatically identify which of the two standard buffer solutions is present: either 4.0 and 7.0 In this step, the standard buffer solution of 4.0 will be identified.

• 3. After the calibration, input the EXIT command in the serial monitor to save the relevant parameters and exit the calibration mode. Note: Only after inputing EXIT command in the serial monitor can the relevant parameters be saved.

• 4.After the above steps, the second point calibration is completed.

  • 6.After completing the above steps, the two-point calibration is completed, and then the sensor can be used for actual measurement. The relevant parameters in the calibration process have been saved to the EEPROM of the main control board.

Sample Code

Please download DFRobot_PH Library first,then install it. How to install Libraries in Arduino IDE?

/*
* file DFRobot_PH.ino
* @ https://github.com/DFRobot/DFRobot_PH
*
* This is the sample code for Gravity: Analog pH Sensor / Meter Kit V2, SKU:SEN0161-V2
* In order to guarantee precision, a temperature sensor such as DS18B20 is needed, to execute automatic temperature compensation.
* You can send commands in the serial monitor to execute the calibration.
* Serial Commands:
* enter -> enter the calibration mode
* cal -> calibrate with the standard buffer solution, two buffer solutions(4.0 and 7.0) will be automaticlly recognized
* exit -> save the calibrated parameters and exit from calibration mode
*
* Copyright [DFRobot](http://www.dfrobot.com), 2018
* Copyright GNU Lesser General Public License
*
* version V1.0
* date 2018-04
*/

#include "DFRobot_PH.h"
#include 

#define PH_PIN A1
float voltage,phValue,temperature = 25;
DFRobot_PH ph;

void setup()
{
Serial.begin(115200);
ph.begin();
}

void loop()
{
static unsigned long timepoint = millis();
if(millis()-timepoint>1000U) //time interval: 1s
{
timepoint = millis();
voltage = analogRead(PH_PIN)/1024.0*5000; // read the voltage
//temperature = readTemperature(); // read your temperature sensor to execute temperature compensation
phValue = ph.readPH(voltage,temperature); // convert voltage to pH with temperature compensation
Serial.print("temperature:");
Serial.print(temperature,1);
Serial.print("^C pH:");
Serial.println(phValue,2);
}
ph.calibration(voltage,temperature); // calibration process by Serail CMD
}

float readTemperature()
{
//add your code here to get the temperature from your temperature sensor
}