Potentiometer Reading help.

[xtech007]

Once again I Ask for your help.
Like I mention Before I'm relatively new to electronics and Picaxe world, but I'm learning and having fun as we go along.
Cool..
I'm trying to get a reading out of a POT. attached to a Force feedback steering wheel (Logitech Driving force EX) to a Picaxe 28X1 via Readadc.
I spliced into the POT. center wire(white) the other 2 wires are red and Black.

PROBLEM: Pot uses power out of the steering controller less then 5 Volts I would say. When attached to the 28X1 it looses its force feed back. it will not self center and it jitters. When the wire is removed from the 28X1 it works just fine, it centers itself.

Reading the the Manual 3 Input Device 2 - Potentiometer
the diagram shows the power for the Pot is supplied by the same circuitry of the pic. Could this be my problem??
If so, is there a solution I might have missed ?

Once again thank you for the Help..

 

[goom]

Do you have the grounds for the PICAXE and steering wheel controller connected together? If not it will definitely not work.
What is the voltage across the POT (i.e across the red and black wires)? It must not be more than the PICAXE supply voltage.

 

[BeanieBots]

Not all pots are used as simple potential dividers.
It is possible that the pot makes up part of oscillator or similar.
Ideally, you should put a 'scope on the wiper and check.
Failing that, as suggested by goom, check with a DVM. (AC and DC).

 

[westaust55]

Potentiometer input (READADC)

If it does prove that the pot is part of an oscillator or similar circuit, one option, space permitting, is to replace it wath a dual gang pot. Then use one section in the original circuit and the second pot element for the PICAXE input.

 

[xtech007]

thanks for the fast reply ..

Once again you guys are great!!!
Sorry for taking too long to respod.

checked the POT voltage and its 4.9 volts.
I will try to tap to the POT ground and added to the ground of the 28X1 ground rail to see what it will do.

I Would try to see if I can Use the pot mention by westaust55
the only problem I see with that is the limited space where its attached.
but I'm willing to make some alterations..

Cheers to all ..
Thanks!!!!!!!!