CO percentage calculation

vicente · **Joined:** Fri Sep 28, 2012 2:28 pm **Posts:** 51

Hello.
I have seen in java code from waspmote demo out the box that CO percentage is calculated in this way:

Quote:

co=PApplet.parseInt((co_signal-co_min)*100/(330-co_min));
if( co<0 ) co=0;

Could I use that equation?
or do you recommend me to apply ppm convert like this CO = pow(10, (log10(COO)-2.302)/(-1.151))?

Thank you.

libelium-dev · **Joined:** Mon Sep 28, 2009 1:06 pm **Posts:** 7453

Vicente,

Yes, you can use it. take a look into this post.

Regards

vicente · **Joined:** Fri Sep 28, 2012 2:28 pm **Posts:** 51

Hello Libelium-dev.
But, Could I use the equation used in your demo out of the box?:

Quote:

co=PApplet.parseInt((co_signal-co_min)*100/(330-co_min));
if( co<0 ) co=0;

It doesn't use: log(R) = a * log(C) + b

Thank you.

libelium-dev · **Joined:** Mon Sep 28, 2009 1:06 pm **Posts:** 7453

Vicente,

that equation was used as an approximation for a certain situation.

It is better for you to use the other equation.

Regards.

vicente · **Joined:** Fri Sep 28, 2012 2:28 pm **Posts:** 51

Hello Libelium-dev.
What is that certain situation?.

Thank you.

libelium-dev · **Joined:** Mon Sep 28, 2009 1:06 pm **Posts:** 7453

vicente,

It was an approximation used for a Waspmote Demonstration, not used to obtain qualitative values, but quantitative ones.

Regards.

vicente · **Joined:** Fri Sep 28, 2012 2:28 pm **Posts:** 51

Thank you Libelium-dev.
It is a cualitative aproximation.