Re: [PD] arduino problem with analog sensors
Try grounding all the unused analog ins(especially a few between the two ins that are cross-talking), ideally shielding the wires would help too. Indeed magnetic fields in those wires do move through space! .b. altern wrote: 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 ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Re: [PD] arduino problem with analog sensors
At a guess, the two transducers are not adequately decoupled with respect to the power supply and I'm guessing the potentiometer is a fairly low resistance and the pressure sensor has a high resistance so that their respective current flow changes are very different. Solutions could be to either 1) Change the power supply to something that can source a higher flow - is it a USB powered thing? 2) Put a big (33,000uF or 68,000uF) capacitors across each sensors supply close to it. On Thu, 12 Nov 2009 18:02:05 +0100 altern wrote: > 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 > > ___ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Re: [PD] arduino problem with analog sensors
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: alte...@gmail.com > To: pd-list@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 > > ___ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Re: [PD] arduino problem with analog sensors
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 > 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: alte...@gmail.com > > To: pd-list@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 > > > > ___ > > Pd-list@iem.at mailing list > > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > > ___ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > > -- http://www.chilemigra.cl http://arselectronicachile.blogspot.com http://www.myspace.com/santorcuato ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Re: [PD] arduino problem with analog sensors
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 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: alte...@gmail.com To: pd-list@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 ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
