A/D Sampling Rate?

Hi, I,m new here but learning fast. I would like to incorporate an Arduino Board into a Metal Detector. I have the circuit designed but I am having trouble finding the right sampling rate that I need to be able to digitize the return signal.

Am I correct in thinking that in order to sample the short 30 microsecond induced current at a resolution of 1 Microsecond per sample that i would need a minimum of 1 MHZ sample rate?

Maybe: http://forum.arduino.cc/index.php?topic=160169.msg1201698#msg1201698

Ray

Thanks Ray, I have read a lot on the forums but I still do not know for sure.

I want to take a sample every micro second but I only need the data in a certain 30 micro second period out of the whole second. I believe It would take a 1 MHZ sample rate to achieve this but seems there are many ways to get around on the Arduino. I believe I will need an external A/D converter but maybe someone out there knows how to get a high sample rate that would achieve my goal with the Arduino... Maybe the Arduino TRE can do the Job?

Any Advice would be greatly appreciated!

The Due can get closer, currently about 2us per sample, though in theory 1MSPS is
achievable it might require re-programming the ADC system at the hardware level
(and a faster internal clock?).

Pulling samples off a separate chip at 1MSPS pretty much limits you to parallel ADCs,
which means lots of pins (Mega?). The standard Arduinos can’t clock SPI faster than 8MHz
for instance, but can generate a 1MHz clock out (using any of the timer/counter modules).

Thanks Mark, That's encouraging News.

I am currently using the Mega with a 3.2" TFT trying to incorporate into the project. I hope the TFT doesn't take all the ports I need for the A/D Converter.

Any Idea on what ADC might be best?

What resolution and dynamic range do you need? You could use the analog comparator and an external resistor network to make your own crude A/D converter. Do it in assembler and you could get 3 or 4 bits of resolution @16Mhz.

I think I could get by with 8 bit for now but more is better. I would like to get up to 24 bit at some point but I found an ADC from DATEL that's 12 bit and 2 MHZ sample and another that's 5 MHZ sample.

Has anyone tested any of these ADC's with Arduino?

GOHO: I think I could get by with 8 bit for now but more is better. I would like to get up to 24 bit at some point but I found an ADC from DATEL that's 12 bit and 2 MHZ sample and another that's 5 MHZ sample.

Has anyone tested any of these ADC's with Arduino?

Check this out: http://hackaday.com/2013/07/08/arduino-oscilloscope-at-five-megasamples-per-second/