Our group is attempting to make an Audio VU Meter and currently we are working on the ADC and DAC using an Arduino Due. I am working on the DAC and I am trying to get a sinewave output from the DAC1 pin. I was able to get a sinewave by using an oscilloscope to measure the voltage that comes out of DAC1 pin. However, our overall goal is to have 8 signals produced from the DAC. For prototyping, we are trying to at least get more than one value to output from a single pin (DAC1). I have seen mentions of multiplexing to solve this issue however I do not know how to code that. Can anyone help please?
What device or devices are going to be connected to the DAC output ?
If you multiplex the signal through the DAC, say by some time slicing method, you would have the problem of reconstructing the signal for the end devices.
You can get DAC chips with multiple channels. This is just an example and may not be suitable for your particular application: MAX5723.
We are using an oscilloscope to measure the voltage value on the DAC1 pin. We also have a function generator connected to produce a waveform.
My main problem is code to make more than one signal to be passes through a single pin.
I suppose if you want to see two signals on the oscilloscope from the same DAC pin, you could apply a different DC offset to each signal and, if necessary, reduce their amplitude before sending it all to the DAC.
But we want to have it so that any signal passed as input to the ADC is the same as the output of the DAC. We are trying to send 8 signals but since the Arduino Due DAC only has two pins (DAC0 and DAC1), we are having trouble as to how we can implement this idea in code.
It seems multiplexing is the only option, but just as a way to test whether this idea would work, we are prototyping to send two signals through a single pin.
Also we want to attempt this with the Arduino Serial Monitor and see what results show up on the serial monitor.
Could use 8 PWM pins on the Arduino Due to output 8 unique sinusoidal PWM signals.
For various ways to drive a VU Meter, this might be interesting.
Yeah but then we would need 8 function generators which we unfortunately do not have
The function generators could be your code.
That link in post #6 looks very interesting. If you use a hardware PWM method to control the VU meter then you can simply use the analogwrite() function on the Arduino. Check which pins on the Due support PWM.