Grove GSR sensor stopped responding to sharp inhale of breath

Other Hardware Sensors
1

Hi all,

I bought 2 Arduino UNO boards, 2 Seeed Base Shields v2 and 2 of the Grove GSR sensors. When I first got them both about 2 months ago they worked very well. I maybe used them both only 3 - 4 times. Yesterday, I noticed that they stopped registering changes when I inhaled deeply (which it registered before, and that is what they should do). Although I noticed changes in the readings when I moved my fingers, one of the units today stopped registering this as well. Even when I do not have anything in the finger cot sensors, the serial monitor does not show a change to negative values (the other one still shows this though). I've isolated every possible part by swapping each component at a time, using a different computer, different code - and it appears to be the Arduino board itself. That seems really strange to me as I would have thought the finger cot sensors would be the problem, but I am a novice, and not sure why that would be. I have reset the boards with both the reset buttons, changed the voltage switch from 3.3 to 5v, but no changes. I am racking my brains as to why this problem is occurring, and can't find anything on google that pertains to my problem. Any help is greatly appreciated!

I have attached a picture, which I hope helps because I am not sure of how to draw a wiring diagram.
Also, this is the code I am using:

const int GSR = A2;
int threshold = 0;
int sensorValue;
int resistance_voltage;
int conductance_voltage;

void setup() {
  long sum = 0; //extended size variable for number storage
  Serial.begin(9600); //setting baud rate

  for (int i = 0; i < 500; i++) //for loop that adds the sensorValue to sum 500 times
  {
    sensorValue = analogRead(GSR);
    sum += sensorValue;
    delay(5);
  }
  float threshold = 3.32 - (sum / 500 * (5.0 / 1023.0)); //average conductance threshold calculated by subtracting max value by sum divided by 500 multiplied by the converted analog to voltage value
  float thresholdMS = threshold * 1000000; //average threshold in micro-Siemens calculated by multipling threshold above by micro-Siemen conversion rate
  Serial.print("threshold = ");
  Serial.println(threshold);
  Serial.print('\n'); //carriage return for easier display
  Serial.print("thresholdMS = ");
  Serial.println(thresholdMS);
}

void loop() {
  int temp; //establishing temp variable
  sensorValue = analogRead(GSR); //reading analog sensor value
  float resistance_voltage = sensorValue * (5.0 / 1023.0); //conversion arduino analog range to voltage
  Serial.print('\n'); //carriage return for easier display
  Serial.print('\n'); //carriage return for easier display
  float conductance_voltage = 3.32 - resistance_voltage; //subtract the max voltage value from the measured loss to get the amount of electrcity being conducted. Inverting the value so it reads conductance as opposed to resistance.
  Serial.print(conductance_voltage); //print the conductance value to serial
  Serial.print('\n'); //carriage return for easier display
  delay(5); //delay serial prints
}

The code may not be totally right (i.e., some unnecessary things on there), because I needed to remove certain lines so I just got the value (I will need to analyse the data later, and that makes it easier).

2

Sorry, picture was too big.

IMAG0093.jpg
IMAG0093.jpg2205×1255 628 KB

3

I have just got one of them to respond to sharp inhale of breathe by clearing the EEPROM with this code:

/*
 * EEPROM Clear
 *
 * Sets all of the bytes of the EEPROM to 0.
 * Please see eeprom_iteration for a more in depth
 * look at how to traverse the EEPROM.
 *
 * This example code is in the public domain.
 */

#include <EEPROM.h>

void setup() {
  // initialize the LED pin as an output.
  pinMode(13, OUTPUT);
  
  /***
    Iterate through each byte of the EEPROM storage.

    Larger AVR processors have larger EEPROM sizes, E.g:
    - Arduno Duemilanove: 512b EEPROM storage.
    - Arduino Uno:        1kb EEPROM storage.
    - Arduino Mega:       4kb EEPROM storage.

    Rather than hard-coding the length, you should use the pre-provided length function.
    This will make your code portable to all AVR processors.
  ***/

  for (int i = 0 ; i < EEPROM.length() ; i++) {
    EEPROM.write(i, 0);
  }

  // turn the LED on when we're done
  digitalWrite(13, HIGH);
}

void loop() {
  /** Empty loop. **/
}

However, the one that wasn't responding to the inhale or the finger movements is still not working.

I have contacted the supplier of the Arduino Uno (I bought it from a site in my country to reduce shipping costs). But I am now suspicious that I have a fake board. I read on the forum that the Uno should use ATmega328 not ATmega328P, and my boards have the ATmega328P...

Can anyone confirm that is a red flag that I have a fake board?!