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PH SENSOR ELECTRODE WITH GAIN BOARD

PH SENSOR ELECTRODE WITH GAIN BOARD

Industrial grade PH sensor

Rs 2,950.00(Add GST...) Add

PH SENSOR ELECTRODE WITH GAIN BOARD




Specification:
• Power : 5.00V
• Module Size : 43 x 32mm(1.69x1.26")
• Measuring Range :0 - 14PH
• Measuring Temperature: 0 - 60 deg c
• Accuracy : ± 0.1pH
• Response Time : < 1min
• pH Sensor with BNC Connector

• Gain Adjustment Potentiometer
• Power Indicator LED


pH stands for potential Hydrogen, and it tells us whether a solution or substance is BASIC (pH above 7.0), ACIDIC (pH below 7.0) or NEUTRAL (pH of 7.0).

Acidic solutions contain a greater concentration of Hydrogen ions (H+)
Basic solutions contain a higher concentration of Hydroxyl ions (OH-).
A plant’s pH needs vary whether they are grown in soil or hydroponics, so it is important to tailor your pH level to your growing method.

The optimal pH range for most common hydroponic crops is between 5.5 and 6.0. If your pH drifts outside of this range, your plant will not be able to uptake certain nutrients.


Our analog pH sensor, specially designed for Arduino controllers is easy to use and can be used as a plug and play solution to measure pH value of a solution without any additional circuit required.
It has an LED which works as the Power Indicator, a BNC connector and PH2.0 sensor interface.
To use it, just connect the pH sensor with BNC connector, and plug the PH2.0 interface into the analog input port of any Arduino controller. With a simple program to ready analog voltage, you will get the pH value easily.

How it works
The pH is a measure of the acidity or alkalinity of a solution, the pH scale varies from 0 to 14.
The pH indicates the concentration of hydrogen ions [H]+ present in certain solutions.
Can be quantified accurately using a sensor that measures the difference of potential between two electrodes: a reference electrode (silver/silver chloride) and a glass electrode is sensitive to hydrogen ion. This is what will form the probe. In addition there are that use an electronic circuit to condition the signal appropriately, and that we can use this sensor with a microcontroller.

Substance approximate pH vaue
Lemon juice 2,4 – 2,6
Cola 2,5
Vinegar 2,5 – 2,9
Orange juice or apple 3,5
Beer 4,5
Coffee 5,0
Tea 5,5
Milk 6,5
Water 7,0
Saliva 6,5 – 7,4
Blood 7,38 – 7,42
Sea water 8,0
Soap 9,0 to 10,0

Pin cofiguration
To   Temperature
Do    Signal the limit of pH
Po     PH value in V
G      Mass of the analog circuit
G      Mass Power
V+     Power supply (5V)

To calibrate the sensor
As we can observe that in the circuit there are two knobs. The one who is more attached to the connector BNCof the probe is the one that regulates the offset, the other is the limit of pH.
• Offset: the mean (range) of the probe oscillates between negative values and positive. The 0 represents a pH of 7.0. To be able to use it with Arduino, this circuit adds an offset value to the value measured by the probe, this way the ADC will only have to take a sample of positive values of voltage. Therefore we'll force a pH of 7.0 by disconnecting the probe from the circuit and short-circuit the inner part of the BNC connector with the outside. With a multimeter we measure the value of the pin Po and adjust the potentiometer to 2.5 V.
• Limit of pH: This knob is for setting a limit value of the circuit for pH sensor that makes the LED red turns on and the signal of pin Do is put in ON.

In addition we need to calculate the conversion of the voltage that will give us the pH sensor to what we will need two reference value of pH and measuring the voltage returned by the sensor on the pin Po. It is better to use a solution from calibration on, there are also in liquid, but is easier to keep the of on. These solutions are sold in different values, although the most common are pH 4.01, pH 6.86 and pH 9.18.
Using the envelopes with pH 4.01 and pH 6.86 we obtain the voltages on the pin Po 3.04 V and 2.54 V, respectively. The sensor is linear so that by taking two points, we can deduce the equation to convert the measured voltage to pH. The formula overall would be y=mx+b, so we have to calculate m and b as x would be the voltage e and the pH. The result is y=-5.70 x+21.34.
Connection with Arduino
To connect it with Arduino, you will need a analog input (A0), power (5V) and two GND that in reality in the sensor circuit are separated but we can use the same.
Code
The code consists of taking 10 samples of the analog input A0, sort them, and discard the highest and the lowest and calculate the average of the six remaining samples converting this value to a voltage in the variable pHVol, then using the equation we have calculated with the reference values of pH become pHVol to pHValue and it is sent on the serial port to view the article in the serial monitor.


const int analogInPin = A0;
int sensorValue = 0;
unsigned long int avgValue;
float b;
int buf[10],temp;
void setup()
{
Serial.begin(9600);
}

void loop() {
for(int i=0;i<10;i++)
 {
 buf[i]=analogRead(analogInPin);
 delay(10);
}
for(int i=0;i<9;i++)
{
 for(int j=i+1;j<10;j++)
 {
  if(buf[i]>buf[j])
  {
   temp=buf[i];
   buf[i]=buf[j];
   buf[j]=temp;
  }
}
}
 

avgValue=0;
for(int i=2;i<8;i++)
avgValue+=buf[i];
float pHVol=(float)avgValue*5.0/1024/6;
float phValue = -5.70 * pHVol + 21.34;
Serial.print("sensor = ");
Serial.println(phValue);

delay(20);

}

Download Arduino Code



 
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