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Calibrating GSR sensor

Posted: Tue Nov 06, 2018 12:37 pm
by r.lawther
Hi,

I've just got my Grove GSR sensor, along with a GrovePi+ and a Raspberry Pi. I'm following the process at http://wiki.seeedstudio.com/Grove-GSR_Sensor/, and I'm adjusting the potentiometer until I get a reading of 512. However my sensor values always jump from around 535 down to ~25, no matter how slowly I turn the screw. Is this normal?
GroveGSR.PNG
GroveGSR.PNG (37.06 KiB) Viewed 1360 times
I also can't seem to get any changes in reading when wearing the sensor. It does seem to be somewhat working, as if I touch the electrodes together I get readings near 0.

I'm using the grove_analog_read.py script from the git repo.

Can you provide me with any hints to get it working properly?

Cheers,

- Rob

Re: Calibrating GSR sensor

Posted: Thu Nov 08, 2018 12:46 pm
by bill.yu
Hi Rob

I just tested it and please use the screw driver to rotate 1 direction first and make it tight. then you can release the screw slowly. here is my output. thanks.


sensor_value = 519
sensor_value = 518
sensor_value = 516
sensor_value = 519
sensor_value = 518
sensor_value = 518
sensor_value = 518
sensor_value = 519
sensor_value = 519
sensor_value = 518
sensor_value = 518
sensor_value = 519
sensor_value = 518
sensor_value = 517
sensor_value = 518
sensor_value = 518
sensor_value = 517

Re: Calibrating GSR sensor

Posted: Tue Jan 15, 2019 10:21 am
by a.vegaramirez76
Hello! I'm in the same case that is described above, also when I connect more than one sensor in one ESP32 board the sensor read incorrect values

Re: Calibrating GSR sensor

Posted: Wed Jan 16, 2019 10:51 pm
by rmarinchev
Hi, I am using seeeduino. Is it normal the following code to still produce the same values, regardless of whether or not I have the sensor connected?

Code: Select all

const int GSR=A0;

void setup(){
  Serial.begin(9600);
}

void loop(){
   Serial.println(analogRead(GSR));
}
I am also trying to follow the wiki tutorial, but I am unable to get any meaningful data from the sensor...

Re: Calibrating GSR sensor

Posted: Fri Feb 01, 2019 6:48 pm
by designnotes.com
rmarinchev wrote:
Wed Jan 16, 2019 10:51 pm
Hi, I am using seeeduino. Is it normal the following code to still produce the same values, regardless of whether or not I have the sensor connected?

Code: Select all

const int GSR=A0;

void setup(){
  Serial.begin(9600);
}

void loop(){
   Serial.println(analogRead(GSR));
}
I am also trying to follow the wiki tutorial, but I am unable to get any meaningful data from the sensor...
This code is just displaying the analog data in the range of 0-1023. Which is a raw data of the sensor. You need to convert it into gas data by using calculations in order to get meaningful out.


I hope it will help you.

Re: Calibrating GSR sensor

Posted: Fri Jul 12, 2019 3:00 am
by excalibas
Can someone explain why calibrate for a value of 512?

Shouldn't we calibrate at 1024 instead? so it is the highest value without wearing the sensor?