Okay, i will look into that option then, just have to find a module that are in europe - so i wouldnt have to wait that long for it tho.

There are many versions of it since PWM to 0-10V is bog standard automation stuff. You will even find them in housings.

In the meantime, or alternatively, you could build up @ericgibbs circuit which is designed for your purpose. I really don't know if it would be a good or better than my approach but you have the parts and you can test.

 

Note that the original circuit has two high-pass filters and two low-pass filters. All of them will work to distort the "squareness" of a square-wave pulse waveform.

ak

 

Hmmm just an exstra look - when i am looking at the PDF of the module, it only says it requires analog input ?

I am so thankfull for you guys want to help me out here.

 

There are many versions of it since PWM to 0-10V is bog standard automation stuff. You will even find them in housings.

In the meantime, or alternatively, you could build up @ericgibbs circuit which is designed for your purpose. I really don't know if it would be a good or better than my approach but you have the parts and you can test.

Yah i will atleast look into it - but i have the parts, if i can use the same OPAMP model ? since i have all the resistors in house so. But do you believe it would work with my DAC pin ? just so i understand the configuration correctly.

 

Note that the original circuit has two high-pass filters and two low-pass filters. All of them will work to distort the "squareness" of a square-wave pulse waveform.

ak

Hmm that might be one of the reasons for the decrease rather fast - but thanks for the note

 

Hmmm just an exstra look - when i am looking at the PDF of the module, it only says it requires analog input ?

I am so thankfull for you guys want to help me out here.

A microphone, as in the example, produces an AC analog signal. AC is not digital, it's analog.

 

Hi,
What is the DAC type number and what is the MCU pin signal type driving the DAC.?
E

 

A microphone, as in there example, prides an AC analog signal. AC is not digital, it's analog.

Okay, yah i wondered about it, but i just though i could make an analog signal to amplify and it would work as well.
but thanks for the clarification.
I will try to make the simple circuit example in here and give it the analog signal from my arduino and see if i can get it to work.

 

Hi,
What is the DAC type number and what is the MCU pin signal type driving the DAC.?
E

øhmm, here i have no clue.
I am using DAC0 on the arduino due board.
the chip on the arduino dueis the atmel atsam3x8eau 2039stb

dont know if that helps ?

 

hi
OK,
Who programmed the Duo and what waveform , frequency etc.. is being output from the pin.?
E

 

hi
OK,
Who programmed the Duo and what waveform , frequency etc.. is being output from the pin.?
E

I am, but its just a basic script:

int led = 31;
// declaring varibles for function
char user_input;
int state;


void setup() {
pinMode(led, OUTPUT);
pinMode(DAC0, OUTPUT);

// setup for the active menu
Serial.begin(9600); //Open Serial connection for debugging
Serial.println("Trigger / DAC for the OPamp ");
Serial.println();
//Print function list for user selection
Serial.println("Enter number for control option:");
Serial.println("1. HIGH value");
Serial.println("2. LOW value");
Serial.println("3. test.");


Serial.println();
}

void loop() {
// range between 0-4095 and for safety do go over 4000, since if the value is to high it can burn the DAC.
while(Serial.available()){
user_input = Serial.read(); //Read user input and trigger appropriate function
if (user_input =='1')
{
analogWriteResolution(12);
analogWrite(DAC0,4000);
delay(10);
Serial.println("value high");
}
else if(user_input =='2')
{
analogWriteResolution(12);
analogWrite(DAC0,0);
delay(10);
Serial.println("value LOW");
}
else if(user_input =='3')
{
//analogWriteResolution(12);
//analogWrite(DAC0,4000);
}
else
{
Serial.println("Option finished.");
}

}
}


It basically just sets the DAC output to max when i press 1 in the serial monitor and goes to 0 when i press 2.
meaning it should give 2.75v or something like that when it goes high and 0.5 ish when it goes low.

 

AC is not digital, it's analog.

I appreciate the support, but ...
RS-232
RS-422
NRZ
Ethernet (UTP, STP)

ak

 

hi Simon,
If you are driving the Duo output with a 0V and say 2.5V as a Step function and feeding that into an AC amplifier all you will get is a Spike output!!

Try an undulating signal from the DAC.
E

 

I appreciate the support, but ...
RS-232
RS-422
NRZ
Ethernet (UTP, STP)

ak

I should say, not inherently digital. Digital signals can be AC but AC signals are not necessarily digital ones, as in the case of the microphone.

 

Hi Simon
Ref this image from a sim.
E
Quote:
It basically just sets the DAC output to max when i press 1 in the serial monitor and goes to 0 when i press 2.
meaning it should give 2.75v or something like that when it goes high and 0.5 ish when it goes low.


If you are driving the Duo output with a 0V and say 2.5V as a Step function and feeding that into an AC amplifier all you will get is a Spike output!!

 

hi Simon,
If you are driving the Duo output with a 0V and say 2.5V as a Step function and feeding that into an AC amplifier all you will get is a Spike output!!

Try an undulating signal from the DAC.
E

Hi Eric

With my lasts circuit i got something like this with high and about 180 degrees flipped once i got it "low" :


But when i measure the output directly from the dac pin its a "constant" level change - if that make sense?

 

But when i measure the output directly from the dac pin its a "constant" level change - if that make sense?

Yes, perfect sense.

 

hi Simon
The R/C AC coupling in your amp is differentiating the square wave input pulse edges.
Use a much faster modulation signal from the Duo.

E

 

hi Simon
The R/C AC coupling in your amp is differentiating the square wave input pulse edges.
Use a much faster modulation signal from the Duo.

E

From what i can get out of the DAC pin, that would be the "highest value" i can get out without burning it.
So i am not sure what you are suggesting i should use - since i direct digital pin would also give a similar value? (3,3V but still) and there i wouldnt be able to adjust the output beside high low?

 

hi,
By faster I mean a higher frequency sine wave, not a higher voltage.

Can you say exactly what you are trying to do with the Duo part of the project, it would help us to understand.

Basically the DAC voltage Step function you are using to test the DAC is OK, BUT it is not suitable for the AC amplifier.
E

Update:
Link.
https://www.arduino.cc/en/Tutorial/DueSimpleWaveformGenerator