Hi, I'm actually using olimex 328 board with 2 EMG shield. The AIN_SEL for first shield is 1. The AIN_SEL for second shield is 3. Supposingly, it means that the analog port for 1 and 2 are taken. I plan to have the remaining 4 analog ports for my 4 force sensitive resistor sensor.
The arrangement of my FSR is similar to this, except the ports taken are 2,3,4,5.
(http://www.imagebam.com/image/68ab10269164027)
The arduino code I used for fsr sensor is here under In-Depth Code for Analog FSR Measurements on this website, http://learn.adafruit.com/force-sensitive-resistor-fsr/using-an-fsr.
The problem I face is there's analog reading for port 4 & 5 as shown
(http://www.imagebam.com/image/310358269164022)
Supposingly, it should be zero value if I didn't apply any force.
(http://www.imagebam.com/image/ee274f269164016)
Is it related to the SDA and SCL of the ports?
I've tested the port 4&5 with only olimex 328 board, it shows the same results.
Please give me advice. Thank you.