Smart pH Sensor

This pH Sensor reads the pH value of any liquid and alerts by SMS with the liquid and its pH value

IntermediateProtip4 hours14,855

Things used in this project

Hardware components

Bolt IoT Bolt WiFi Module

Arduino UNO

pH Sensor

Male/Female Jumper Wires

9V battery (generic)

9V Battery Clip

Software apps and online services

Bolt IoT Bolt Cloud

Bolt IoT Android App

Arduino IDE

Twilio SMS Messaging API

Story

In chemistry, pH is a scale used to specify how acidic or basic a water-based solution is. Acidic solutions have a lower pH, while basic solutions have a higher pH. At room temperature, pure water is neither acidic nor basic and has a pH of 7.

pH range table

pH measurement is used in a wide variety of applications: agriculture, wastewater treatment, industrial processes, environmental monitoring, and in research and development.

pH is a measure of the acidity or alkalinity of a solution.... The greater the concentration of H+ the more acidic the solution and the lower the pH.

To Calculate pH and [H+]: The equilibrium equation yields the following formula for pH : pH = -log 10 [H+] [H+] = 10-pH

In other words, pH is the negative log of the molar hydrogen ion concentration or the molar hydrogen ion concentration equals 10 to the power of the negative pH value.

pH Sensor

A pH meter is a scientific instrument that measures the hydrogen-ion activity in water-based solutions, indicating its acidity or alkalinity expressed as pH.

The pH meter is used in many applications ranging from laboratory experimentation to quality control.

pH probes measure pH by measuring the voltage or potential difference of the solution in which it is dipped.

Hence, a pH probe measures the potential difference generated by the solution by measuring the difference in hydrogen ion concentration using the Nernst equation and displays the pH as output.

STEPS to do this project:

Do the connections of the circuit as shown below
Create a product on the Bolt Cloud (https://cloud.boltiot.com/home)
Select the code option, type the code and save it with javascript (.js) extension
Link the product with your Bolt device
You can type your python code either in Digital Ocean (https://cloud.digitalocean.com/login) or in the Oracle VM Virtual Box (https://www.virtualbox.org/wiki/Downloads) ubuntu server (http://releases.ubuntu.com/16.04/ubuntu-16.04.6-server-i386.iso)
In the ubuntu server, type your python code with suitable file name and extension.py or copy the code given
Connect the Bolt module to power supply and run the python code

Code

import json, time, conf
from boltiot import Bolt, Sms #Import Sms and Bolt class from boltiot library

value1 = 0
value2 = 6.5
value3 = 7.5
value4 = 14

mybolt = Bolt(conf.API_KEY, conf.DEVICE_ID) #Create object to fetch data
sms = Sms(conf.SID, conf.AUTH_TOKEN, conf.TO_NUMBER, conf.FROM_NUMBER) #Create object to send SMS
response = mybolt.serialRead('10')
print response

while True:
    print("Reading Sensor Value")
    response = mybolt.serialRead('10')  #Fetching the value from Arduino
    data = json.loads(response)
    ph_value = data['value'].rstrip()
    print("pH Valueis:"+str(data['value']))
    try:
        if ph_value > value1 and ph_value < value2:
            print("Making request to send SMS")
            response = sms.send_sms("The liquid is ACIDIC. pH value of the liquid is:"+str(ph_value))
            print("Response recieved:"+ste(response.status))
        elif ph_value > value2 and ph_value < value3:
            print("Making request to send SMS")
            response = sms.send_sms("The liquid is NEUTRAL. pH value of the liquid is:"+str(ph_value))
            print("Response recieved:"+ste(response.status))
        elif ph_value > value3 and ph_value < value4:
            print("Making request to send SMS")
            response = sms.send_sms("The liquid is ALKALINE. pH value of the liquid is:"+str(ph_value))
            print("Response recieved:"+ste(response.status))
    except Exception as e:
        print("Error occured: Below are the details")
        print(e)
    time.sleep(100) #reads sensor value for every 100 seconds

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(100);
 }
 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 + 8.65;
 Serial.print("pH Value = ");
 Serial.println(phValue);
 
 delay(20);
}