Multiple Analogread at the same time?

Hello

I am beginner for Arduino meg 2560.

I am trying to get multiple analog signals at the same time from the different sensors.

I followed example for analog read and it showed taking the date from one single channel.

Is there anyway that I can get the more than 10 analog signals at the same time?

Also, it seems like analog input can take the voltage data 0~5V into 0~1023.

Can analog input of Mega 2560 take AC current signal?

Thanks for your help!

There is only one A/D converter so therefore you can not get more than one reading at any time. There are very few occasions you need similtainous readings.

To get more analogue Inputs you multiplex them with an analogue switch.

The input voltage on a chip should not be greater than or less than the chip's power rails. So the only AC signal you can read is one that has a DC bias so it never goes outside these values.

Grumpy_Mike:
There is only one A/D converter so therefore you can not get more than one reading at any time. There are very few occasions you need similtainous readings.

To get more analogue Inputs you multiplex them with an analogue switch.

The input voltage on a chip should not be greater than or less than the chip's power rails. So the only AC signal you can read is one that has a DC bias so it never goes outside these values.

I figured out I may not need to read analog signals simultaneously.
It should be enough if it can read fast enough to be considered "simultaneously" maybe millisecond for one reading?

I know the range it can read cannot go up the bias of the board.

I want to know whether the analog input can read AC current. It seems like it can just read voltage.

If the input signal is current, then should I put a resistor before the board analog input?

Thanks

I want to know whether the analog input can read AC current.

I think you are confusing things. You can not have an alternating current without having an alternating voltage.

But if for some reason you do have an alternating current purely then you put a resistor in line and measure the voltage across it. Not as you said in series.

What is your source of this alternating current?

Grumpy_Mike:
So the only AC signal you can read is one that has a DC bias so it never goes outside these values.

As a matter of interest Mike, how do you actually do that? I understand the objective: "lift" the whole wave by an amplitude so that the previous -V is 0 and the previous +V is now +2V.

But what's the physical setup please?

It is a simple voltage divider with identical resistors to each rail connected to the analogue input. Then AC couple to the analogue input using a capacitor. Like the front end of this circuit.

http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/

Thanks Mike- I'll have a play based on that. Always on the lookout for things to see on my new o'scope....

Always on the lookout for things to see on my new o'scope..

My favorite waveform is the output of a notch filter being fed with a square wave with the frequency of the notch filter. Can you predict what it will look like?

Grumpy_Mike:
Can you predict what it will look like?

Not until I find out what a notch filter is, no. But I will investigate that; Messrs Google to the rescue.....

(My next purchase (purely on basis that my daughter starts her undergrad in engineering in the new year, it's not for me at all, honest) is a function generator.)

You have an Arduino now - why not program your own function generator?