Finding pre pre value from continuous sensor reading.

Projects Programming
1

This may be a odd or really stupid question... but i am having trouble comparing the current reading from a sensor to the previous previous reading....

500 --> comparing this
300
200 --> to this

I am able to compare the previous values but am confused about the prepre value :confused:

i tried this:

void detectGreen()
{
ppColor = preColor;
color = analogRead(4);

if(color < ppColor - 50);
   Stop();

preColor = color;

delay(60);

but it works the same as comparing the previous value to the current value...

So i was hoping someone could help me out with the obviously wrong logic it would be much appreciated!

Thank you!

3

It worked! Thank you... yeah it makes sense once you go through it. I wish i had a debugger would make stuff much easier. Also the semi colon was just a typo, i prefer to not use {} when i can to keep the code looking 'clean', and yeah i only want the Stop() to be part of the if statement.

Thanks

5

I would suggest that you put your samples in a short circular array, and then you can find any of the recent previous samples easily.