[PD] arduino problem with analog sensors

Jose Luis Santorcuato santorcuato76 at gmail.com
Thu Nov 12 20:44:05 CET 2009


Hi, maybe the potentiometer need a resistor,... if the potentiometer is a 10
kohms maybe yo need a resistor, i prefer work with 50 kohms potentiometers.

Using a protoboard, you must connect a general ground and  general voltage,
the wire to analog is the middle wire, check the pwm or outputs are closed.

Best regards

José
2009/11/12 <martin.peach at sympatico.ca>

>  The microcontroller in the Arduino has a single sampling capacitor that
> can be connected to any one of the analog pins.
> It will charge up to the voltage on the pin if enough charged particles are
> available on the pin (or a path less than about 10kohm exists to a source of
> current).
> The cap is not discharged by the analog-to-digital conversion process or
> between samples except through leakage.
> If no charge is available on the pin the capacitor will continue to slowly
> drain its charge from the previous sample.
> It's normal and harmless unless you are in a high-voltage environment like
> a thunderstorm or a nylon carpet, where much more than 5V could accumulate
> on an open pin. Then it's best to ground unused inputs.
>
> Martin
>
>
> > Date: Thu, 12 Nov 2009 18:02:05 +0100
> > From: altern2 at gmail.com
> > To: pd-list at iem.at
> > Subject: [PD] arduino problem with analog sensors
>
> >
> > hi
> >
> > not a PD question I guess... i dont know much of electrical stuff. i am
> > connecting two analog sensors to the arduino. One is a pressure sensor
> > and the second a potentiometer, they are both from an old icube.
> >
> > i noticed that when i raise the potentiometer (analog pin 5) the
> > pressure sensor (analog pin 2) reports values ranging 0 to ~0.16
> > increasing together as the potenciometer goes up. It is like some kind
> > of residual noise comming from pin 5 that goes into pin 0.
> >
> > the power cables of both sensors go together to 5v inlet of the arduino
> > and the ground cables go to ground pin, each of the data cable goes to
> > its separate analog pin.
> >
> > I am using arduino from Pure Data extended using latest Firmata, so i am
> > just filtering out any value smaller than 0.16 coming from analog pin 0.
> >
> > is there anything I am doing wrong? or is this normal?
> >
> > thanks
> >
> > enrike
> >
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-- 
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http://arselectronicachile.blogspot.com
http://www.myspace.com/santorcuato
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