Hi there!
I would like to ask you if it is possible to read an analog input using arduino motor shield while a DC motor is going forward and backward. I have a big problem when I'm trying to do this because a delay of 90ms is necessary in order to move the DC motor and I need to sense an analog input with a sampling time of Ts=0.01s. Could you advice me please?
Thank you!

Thanks Pito !.

Hello:
I want to ask you if it is possible to read a voltage signal +/- 4 volts using Arduino. It is a sinus signal, which is going from +4volts to -4volts and vice versa.
Could you explain me how to do that step by step.
Thank you very much for your help.

Hi my friend:
what do you mean by negative pin ? is it GND ? , I have tried tuning a negative value for analogWrite --- PWM pin 9; but it just can send a maximum voltage around 4.96 volts. In other words, It is not possible to get a negative voltage directly from arduino. I think it is necessary to design an external circuit to obtain that value. But I have no idea about how to do it.
Waiting for responses
thanks for your help

Hello my friend:
So the waveform can be for example v=5sin(2*pi*frequency), frequency=3Hz.
Using arduino is I think impossible to get an oscillating voltage between +/- 5 volts. Because the  arduino output voltage is from 0 to 5 volts.
Any data acquisition card has that possibility but is veeery expensive. I can't pay that
How can I resolve my problem using arduino?
or there is not solution?
thank you for your help my friend.

Thank you for your response. So, the problem I have is as follows.
I have an input voltage, for example 5 DCV, which will be applied for 2 minutes. So I would like to obtain an output voltage oscillating between -5 and +5 volts. How can I get that ? is it possible ?
I have no experience with electronics, but I need to do that for my school project.
Thank you.

Hi everyone:
I would like to ask you how is it possible to change the output voltage from arduino (5 DCV) into a +/- 5 DCV?
Thank you for your help.

I think Arduino is not the best way in order to test a control strategy in real-Time. But I will try it once again. In spite of that I think a Data acquisition card should be the best choice. May be is more difficult but you can apply advanced control strategies. I dont know may be it is possible to do it with Arduino. For example if I want to test a linear quadratic controller, I dont know if Arduino will be able to calculate the state estimation of the system at each sampling time in order to apply a closed-loop control using, of course, the corresponding matrix gain, which can be obtained solving the Riccati Equation using the corresponding state-space representation of the analyzed system.
That's why I need to find, firstly, the state model of the system.
Which kind of input signal I can use for the DC motor and how can I deal with the potentiometer if I can just turn it from 0 to 300 degrees. It is difficult. I'm waiting some advice.
Thank you for reading

 

The position of the DC motor should be detected by the potentiometer.

Yeah ! exactly !
But I dont know if that is possible with the things I have.
SOS

Hola a todos:
Quisiera preguntarles si es posible, solo teniendo un motor DC y un potenciometro colocado al final del eje de giro, obtener el modelo matematico del motor DC. El potenciometro gira de 0 a 300 grados y cuando probe el motor a penas le puse 3 voltios no se cuantas vueltas dio. eso es mas de 300 grados podrian ayudarme con este problema.
Cordiales saludos.

Hi there:
I would like to ask you if it is possible to obtain the mathematical representation of a DC motor using a potentiometer connected to the motor shaft and Arduino UNO board.

Technical Parameters:
the potentiomer can be turned from 0 to 300 degrees.
DC motor voltage 7V.
Arduino UNO board.
Motor shield.

Can somebody help me with this?

Pues me parece que seria bueno que uses una protoboard y pases el ground a ella y lo mismo podrias hacer con el voltaje del pin. Y pues en la protoboard podrias poner tantos piezos como gustes.
saludos amigo

Hola Cheyenne:
Gracias por tu respuesta. Bueno lo que tengo es un motor DC sin engranajes algo como esto
http://upload.wikimedia.org/wikipedia/commons/f/f6/Electric_motors_en.jpg
al final del eje del motorcito he puesto un potenciometro el cual deberia sensar el angulo de giro, y eso es todo. Bueno para el control de la posicion del motorcito necesito usar la placa Arduino UNO, la arduino motor shield y cosas como transistores resistencias etc en caso que sea necesario.
El diseno del regulador no es problema. el problema es la obtencion de modelo matematico del motorcito. Cuando pongo en marcha el motorcito con solo 3 voltios pues el eje gira no se cuantas vueltas por segundo y pues a mi parecer el potenciometro no funcionara ya que solo aguanta giro de 0 a 300 grados.
que podria hacer, necesito ayuda urgente.
cordiales saludos