[PD] arduino problem with analog sensors

[altern]

thanks to everyone for the answers!


Jose Luis Santorcuato(e)k dio:
> 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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> 
>