Can I read multiple analog inputs simultaneously?

Other Hardware Sensors
1

I am working on a project that uses 4 analog inputs to read sound information. However, according to the Arduino official documentation, the minimum processing time for analogRead() is about 0.1ms and, if I use these codes:

sample [0] = analogRead (A0);
sample [1] = analogRead (A1);
sample [2] = analogRead (A2);
sample [3] = analogRead (A3);

... it will take at least 0.4ms to read all the 4 inputs. So, no matter how fast my algorithm runs, one loop() will take at least 0.4ms, which means the frequency of sampling is at most 2500Hz. This sampling rate is quite impractical to process sound data.

All I want to know is, are there any ways to speed up? Like read A0~A4 inputs parallel or something simultaneously?

Thanks!

2

For an Arduino Uno (not sure of other Arduino boards).
There is no way to read analog inputs simultaneously. There is only one ADC and the inputs are multiplexed into that one ADC. You can speed up conversion by changing the ADC clock at some expense to resolution . You can access the ADC hardware directly to sample faster. But there will always be time skew between channels. To do simultaneous sampling you need an ADC per channel or sample and hold units for each channel that are triggered all at once and then multiplexed into one ADC (beware inter-channel droop).

3

If you want true "simultaneous sampling" then you need a part like this:

4

Course, you're still limited to reading out one channel of info at a time. But they will all be captured & converted at the same time.

5

The only Arduino solution, for two channels, is the Teensy 3.2. It has two ADCs that can be triggered at the same time using the companion ADC library. You could trigger two Teensies with a common interrupt pulse but that does not guarantee a perfect sync. The Robin2 solution is best for true sync alignment.

6

If you want to do audio processing the arduino is the wrong platfoirm.

You need DSP devices - try AD, ON-SEMI, crystal etc etc, who supply development kits

thes kits have fast high resolution ADs and DAs and the processors
have fast mutiply/accumulate registers neccesary for filtering etc.

regards.

Allan