1

I am trying to strengthen the signal from my MQ135 air quality sensor so it can detect aerosols from 3 feet away, as, currently as it stands the resolution is pathetic, it only blips from 0.21 to 0.58 when you practically insert the sensor into the nozzle of a bottle full of vinegar/rubbing alcohol.

It would be ideal if you could guide me as to what sort of signal amplifier to buy to strengthen the signal coming from this board?

Alternatively: Could I increase the sensitivity of this sensor?

I'd like to plot this to a graph at some point, so I will be working on an ASP.NET app that tells me if there are any aerosols in my room or not.

enter image description here

Here's the code:

/*
  Graph

 A simple example of communication from the Arduino board to the computer:
 the value of analog input 0 is sent out the serial port.  We call this "serial"
 communication because the connection appears to both the Arduino and the
 computer as a serial port, even though it may actually use
 a USB cable. Bytes are sent one after another (serially) from the Arduino
 to the computer.

 You can use the Arduino serial monitor to view the sent data, or it can
 be read by Processing, PD, Max/MSP, or any other program capable of reading
 data from a serial port.  The Processing code below graphs the data received
 so you can see the value of the analog input changing over time.

 The circuit:
 Any analog input sensor is attached to analog in pin 0.

 created 2006
 by David A. Mellis
 modified 9 Apr 2012
 by Tom Igoe and Scott Fitzgerald

 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/Graph
 */

void setup() {
  // initialize the serial communication:
  Serial.begin(9600);
}

void loop() {
  // send the value of analog input 0:
  Serial.println(analogRead(A0));
  // wait a bit for the analog-to-digital converter
  // to stabilize after the last reading:
  delay(20);
}

/* Processing code for this example

 // Graphing sketch


// This program takes ASCII-encoded strings
// from the serial port at 9600 baud and graphs them. It expects values in the
// range 0 to 1023, followed by a newline, or newline and carriage return

// Created 20 Apr 2005
// Updated 24 Nov 2015
// by Tom Igoe
// This example code is in the public domain.

import processing.serial.*;

Serial myPort;        // The serial port
int xPos = 1;         // horizontal position of the graph
float inByte = 0;

void setup () {
  // set the window size:
  size(400, 300);

  // List all the available serial ports
  // if using Processing 2.1 or later, use Serial.printArray()
  println(Serial.list());

  // I know that the first port in the serial list on my mac
  // is always my  Arduino, so I open Serial.list()[0].
  // Open whatever port is the one you're using.
  myPort = new Serial(this, Serial.list()[0], 9600);

  // don't generate a serialEvent() unless you get a newline character:
  myPort.bufferUntil('\n');

  // set inital background:
  background(0);
}
void draw () {
  // draw the line:
  stroke(127, 34, 255);
  line(xPos, height, xPos, height - inByte);

  // at the edge of the screen, go back to the beginning:
  if (xPos >= width) {
    xPos = 0;
    background(0);
  } else {
    // increment the horizontal position:
    xPos++;
  }
}


void serialEvent (Serial myPort) {
  // get the ASCII string:
  String inString = myPort.readStringUntil('\n');

  if (inString != null) {
    // trim off any whitespace:
    inString = trim(inString);
    // convert to an int and map to the screen height:
    inByte = float(inString);
    println(inByte);
    inByte = map(inByte, 0, 1023, 0, height);
  }
}

*/

/* Max/MSP v5 patch for this example
 ----------begin_max5_patcher----------
1591.3oc0YszbaaCD9r7uBL5RalQUAO3CvdyS5zVenWZxs5NcfHgjPCIfJIT
RTxj+6AOHkoTDooroUs0AQPR73a+1cwtK3WtZxzEpOwqlB9YveAlL4KWMYh6
Q1GLo99ISKXeJMmU451zTUQAWpmNy+NM+SZ2y+sR1l02JuU9t0hJvFlNcMPy
dOuBv.U5Rgb0LPpRpYBooM3529latArTUVvzZdFPtsXAuDrrTU.f.sBffXxL
vGE50lIHkUVJXq3fRtdaoDvjYfbgjujaFJSCzq4.tLaN.bi1tJefWpqbO0uz
1IjIABoluxrJ1guxh2JfPO2B5zRNyBCLDFcqbwNvuv9fHCb8bvevyyEU2JKT
YhkBSWPAfq2TZ6YhqmuMUo0feUn+rYpY4YtY+cFw3lUJdCMYAapZqzwUHX8S
crjAd+SIOU6UBAwIygy.Q1+HAA1KH6EveWOFQlitUK92ehfal9kFhUxJ3tWc
sgpxadigWExbt1o7Ps5dk3yttivyg20W0VcSmg1G90qtx92rAZbH4ez.ruy1
nhmaDPidE07J+5n2sg6E6oKXxUSmc20o6E3SPRDbrkXnPGUYE.i5nCNB9TxQ
jG.G0kCTZtH88f07Rt0ZMMWUw8VvbKVAaTk6GyoraPdZff7rQTejBN54lgyv
HE0Ft7AvIvvgvIwO23jBdUkYOuSvIFSiNcjFhiSsUBwsUCh1AgfNSBAeNDBZ
DIDqY.f8.YjfjV1HAn9XDTxyNFYatVTkKx3kcK9GraZpI5jv7GOx+Z37Xh82
LSKHIDmDXaESoXRngIZQDKVkpxUkMCyXCQhcCK1z.G457gi3TzMz4RFD515F
G3bIQQwcP3SOF0zlkGhiCBQ1kOHHFFlXaEBQIQnCwv9QF1LxPZ.A4jR5cyQs
vbvHMJsLll01We+rE2LazX6zYmCraRrsPFwKg1ANBZFY.IAihr8Ox.aH0oAL
hB8nQVw0FSJiZeunOykbT6t3r.NP8.iL+bnwNiXuVMNJH9H9YCm89CFXPBER
bz422p8.O4dg6kRxdyjDqRwMIHTbT3QFLskxJ8tbmQK4tm0XGeZWF7wKKtYY
aTAF.XPNFaaQBinQMJ4QLF0aNHF0JtYuHSxoUZfZY6.UU2ejJTb8lQw8Fo5k
Rv6e2PI+fOM71o2ecY1VgTYdCSxxUqLokuYq9jYJi6lxPgD2NIPePLB0mwbG
YA9Rgxdiu1k5xiLlSU6JVnx6wzg3sYHwTesB8Z5D7RiGZpXyvDNJY.DQX3.H
hvmcUN4bP1yCkhpTle2P37jtBsKrLWcMScEmltOPv22ZfAqQAdKr9HzATQwZ
q18PrUGt6Tst2XMCRUfGuhXs6ccn23YloomMqcTiC5iMGPsHsHRWhWFlaenV
XcqwgCQiGGJzptyS2ZMODBz6fGza0bzmXBj7+DA94bvpR01MffAlueO7HwcI
pWCwmzJdvi9ILgflLAFmyXB6O7ML0YbD26lenmcGxjVsZUN+A6pUK7AtTrPg
M+eRYG0qD9j4I7eEbco8Xh6WcO.or9XDC6UCiewbXHkh6xm5LiPEkzpJDRTu
mEB44Fgz4NCtJvX.SM1vo2SlTCZGAe7GZu6ahdRyzFOhYZ+mbVVSYptBw.K1
tboIkatIA7c1cTKD1u.honLYV04VkluHsXe0szv9pQCE9Ro3jaVB1o15pz2X
zYoBvO5KXCAe0LCYJybE8ZODf4fV8t9qW0zYxq.YJfTosj1bv0xc.SaC0+AV
9V9L.KKyV3SyTcRtmzi6rO.O16USvts4B5xe9EymDvebK0eMfW6+NIsNlE2m
eqRyJ0utRq13+RjmqYKN1e.4d61jjdsauXe3.2p6jgi9hsNIv97CoyJ01xzl
c3ZhUCtSHx3UZgjoEJYqNY+hYs5zZQVFW19L3JDYaTlMLqAAt1G2yXlnFg9a
53L1FJVcv.cOX0dh7mCVGCLce7GFcQwDdH5Ta3nyAS0pQbHxegr+tGIZORgM
RnMj5vGl1Fs16drnk7Tf1XOLgv1n0d2iEsCxR.eQsNOZ4FGF7whofgfI3kES
1kCeOX5L2rifbdu0A9ae2X.V33B1Z+.Bj1FrP5iFrCYCG5EUWSG.hhunHJd.
HJ5hhnng3h9HPj4lud02.1bxGw.
-----------end_max5_patcher-----------

 */
  • 1
    so to answer the question: it turns out there is a different sensor for every different detectable out there....what a nightmare! Ammonia - MQ137 Carbon Monoxide - MQ-7 Chlorine - MQ 7 ChlorineDioxide - MQ2 EthyleneOxide - MQ-2 Fluorine - MQ-3 Hydrazine Hydrogen - MQ-8 HydrogenFlouride - MQ-8 Hydrogen Sulfide - MQ136 NitricOxide - MQ-7 NitrogenDioxide - MQ-4 Oxygen Grove - Gas Sensor(O2) SKU: 101020002 Ozone - mq-3 Phosgene mq-7 Phosphine mq-7 Silane - MQ-6 SulfurDioxide MQ-136 – Ycombinatordev Apr 12 '16 at 14:01
  • It will be more clear what you want answered if you address one topic per post. What sensor to use; how to set sensitivity; how to plot data – those three issues can be addressed separately. It wastes time to mash them up together. – James Waldby - jwpat7 Apr 12 '16 at 17:07
  • What board is it precisely? Googling "MQ135" shows a discrete part that needs a variable calibration resistance, and it must then be calibrated to your application. Depending on the board, it might already have some conditioning/amplification. – Dave X Apr 13 '16 at 2:13
  • Thanks Dave, it's just an arduino board, I've twisted the variable pot on it to get some fine tuned readings....i did not see any significant amplification...olimex.files.wordpress.com/2015/05/mq-1.jpg – Ycombinatordev Apr 13 '16 at 8:16
  • int sensorValue; int pin8 = 8; void setup() { Serial.begin(9600); pinMode(pin8, OUTPUT); } void loop() { sensorValue = analogRead(0); // read analog input pin 0 Serial.print(sensorValue, DEC); //prints the value read Serial.println("ppm"); if (sensorValue > 500) { //Activate digital output pin 8 - the LED will light up digitalWrite(pin8, HIGH); } else { // Deactivate digital output pin 8 - the LED will not light up digitalWrite(pin8, LOW); } delay(50); } – Ycombinatordev Apr 15 '16 at 9:32
0
int sensorValue;
int pin8 = 8;
void setup()
{
  Serial.begin(9600);
  pinMode(pin8, OUTPUT);

  }

  void loop()
  {
    sensorValue = analogRead(0); // read analog input pin 0
    Serial.print(sensorValue, DEC); //prints the value read
    Serial.println("ppm");
    if (sensorValue > 500) {
      //Activate digital output pin 8 - the LED will light up
      digitalWrite(pin8, HIGH);
    }
    else
    {
      // Deactivate digital output pin 8 - the LED will not light up 
      digitalWrite(pin8, LOW);

    }
    delay(50);

}

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.