Analog inputs overriding each other

Forum 2005-2010 (read only) Hardware Interfacing
1

I am using a 6DOF razor motion sensor IMU 6DOF Razor - Ultra-Thin IMU - SEN-09431 - SparkFun Electronics

three pressure sensors Force Sensitive Resistor - Square - SEN-09376 - SparkFun Electronics

and three softpots Softpot Rotary Potentiometer - SEN-08678 - SparkFun Electronics

and I am connecting all of those to arduino mega analog inputs - this I then connect to Pure Data (the program)

I have no problems when I connect the razor and pressure sensors but when I connect the softpots and press them, then the other sofpot value outputs all go to 1 (they range from 0 -1) along with the one being pressed - regardless of where they are being pressed (this is a linear potentiometer)

So in other words it seems that the softpot outputs are somehow bleeding over to one another, as well as not giving an accurate (to say the least) output value.

When I only connect one softpot to the arduino it works fine, but with more than one they start to give me said trouble

anyone have any good ideas why this happens.

:-/

2

When I only connect one softpot to the arduino it works fine, but with more than one they start to give me said trouble

anyone have any good ideas why this happens.

Well if one works fine then all three should. If you could post a pic or drawing of how your are wiring them up and post your code showing how your are reading and scaling the analog input pins, possibly we can help.

Lefty

3

The soft pot when not pressed is open circuit. Therefore the input is floating. Use a 100K pull down resistor to stop them picking up stuff from the other channel.