Need help with Arduino Polygraph project

[tron_ifightfortheusers]

Hello all,

I'm a complete Arduino noob.

I'm (attempting) to complete an Arduino Polygraph Machine project that I came across on Instructables.

If you take a look at the page, it seems that there's some information that is missing from this Instructable. First, there's no "real" schematic that shows where each sensor is connected to the board...and from what I can tell, the picture that somewhat illustrates all the components is not accurate.

After some intense research, I think I've come up with more accurate wiring than illustrated in the picture above:

For the SHT20 Temperature and Humidity sensor:

Sensor <--> Arduino
VCC = 3.3V
GND = GND
SDA = A4
SCL = A5

For the Pulse sensor:

Sensor <--> Arduino
Positive (red) = 5V
Negative (black) = GND
SIG (purple) = A3

Also, I have no idea where the leads for the ECG pads would be connected to the board. They are supposed to use impedance pnuemography to measure breathing rates. All the author says about this in his article to is "read the impedance pneumography way to measure breath rate and complete your circuit according to your interest".

And lastly, I've never done any programming for Arduino, so I'm having issues with the sketch. I'm not seeing anything for the ECG pads/breathing rate sensors aside from the one line (line 24 = Serial.println(analogRead(A2)); // Read Breath rate) in the Lie_Detector.ino listed on the Instructables page for this project. I'm also still confused about getting all the code for the three separate sensors into one sketch...so I'm going back now to re-research the programming side for Arduino.

Any help at all in getting this in a clear, easy-to-read/follow way for a noob would be greatly appreciated!

[jremington]

Not a polygraph, but you would have a much better "getting started" experience with the Myoware kit and tutorial from Sparkfun.

Arduino Forum members don't think much of Instructables. Many are written by people who have little to no idea about what they are doing, and there is no quality control over postings.

[tron_ifightfortheusers]

jremington, thanks for the respose!

That looks like it might be an interesting second or third "getting started" experience, but I do have to focus on this one project for various reasons.

[xfpd]

@tron_ifightfortheusers

Any help

Upload the program code. (1) in your IDE, format the code using CTRL-T (2) click the < CODE > button in your message/reply box, then (3) find the highlighted sentence ```type or paste code here``` and paste your code over the words (not the tick marks). That will make the code readable and copyable. Next; cleanup.

The sketch relies on the libraries. It starts the SHT20 object, reads humidity, temperature from the SHT20, then reads A3 for pulse and A2 for breathing... that's all.

#include "Wire.h"
#include "DFRobot_SHT20.h"

DFRobot_SHT20    sht20;

void setup()
{
    Serial.begin(9600);
    sht20.initSHT20();                                  // Init SHT20 Sensor
    delay(100);
    sht20.checkSHT20();                                 // Check SHT20 Sensor
}

void loop()
{
    float humd = sht20.readHumidity();                  // Read Humidity
    float temp = sht20.readTemperature();               // Read Temperature
    Serial.print(temp, 2);
    Serial.print(",");
    Serial.print(analogRead(A3));                 // Read Pulse sensor value
    Serial.print(",");
    Serial.print(humd, 1);
    Serial.print(",");
    Serial.println(analogRead(A2));                 // Read Breath rate  
}

The DFRobot SHT-20 library

GitHub - DFRobot/DFRobot_SHT20

The PulseSensorPlayground library (read the README.md for how-to-use)

GitHub - WorldFamousElectronics/PulseSensorPlayground: A PulseSensor library (for Arduino) that collects...

This is the PDF for the Impedance Pneumography...
Impedance pneumography.pdf (698.0 KB)

[tron_ifightfortheusers]

The diagram shows 2 ECG pads, one of which is wired to A2 on the board...as well as A2 being indicated for the breath rate in the sketch.

The diagram also shows the 2nd ECG pad being wired into the 5V pin on the board...the same as the + from the Pulse sensor...is this correct???

[xfpd]

This is a fraud project on ElectroPeak.com... although this "polygraph" can be done. I just would not follow ElectroPeak.com. They only want your clicks, not caring about their failure of providing accurate information.

For example; the text in the "ElectroPeak.com" (a direct copy of Instructables.com) drawing states "The ECG pads [are] used to [measure] breath rate." This web site project is fake. ECG is an acronym for Electro Cardio Graph/Gram. "Cardio" means "heart." It will NOT read pulmonary (breathing) activity.

An ECG monitor will have three pads connected to an amplifier, with the amplifier output connected an analog input on the Arduino. Two digital wires will be connected between the Arduino and the ECG amplifier for noting problems with the pads (on/off).

Do you want to build a Polygraph? Have you purchased parts for this?

[Grumpy_Mike]

@tron_ifightfortheusers

but I do have to focus on this one project for various reasons.

Is one of the reasons that this is a class project or assignment of some sort, and you want us to do it for you?