What would be fast enough to store (and sample from input) at 5 mbyte/sec (whether that's over USB, SD, or whatever) with no manipulation on the data? The upcoming Tre? Galileo? pcDuino? Something else?
I chose 5 mbyte/sec as a reference value, as a line scanner I use at work stores about 550mb in a couple of minutes, iirc, it uses a 486 onboard processor and 256MB SDRAM.
AFIK.
5mb per sec is well beyond what the Arduino can achieve writing to SD memory, mainly because the Arduino doesnt do SDIO protocol to an SD card.
With the sizes of data you want to store, only SD and disk would be large enough.
And . AFIK. 5mhz sampling is also beyond what the ADC is capable of with any reasonable level of precision.
You are better off using a different board that has a lot of on board ram and a DAC.
i.e something like the BeagleBone Black may be suitable (You'd need to check the specs), as I'm not sue of the ADC speed on that board.
You may also want to look at a Raspberry PI, but AFIK it doesnt have an ADC so you'd need to have a separate external very fast ADC.
If both of those are too slow, you'd need to look at an FPGA solution.
I've got my eye on a 25 msps/12-bit ADC that'd be fine for my purposes, but then of course, still limited by the sampling rate of the digital inputs. The processing power of the Galileo and others should technically be enough, but yeah.
I'll have a look at the beagle.
I have a 40msps 8-bit ADC that I used to make a DSO connected to a PC parallel port years ago. More recently I rebuilt the DSO board so it can send data to a PC using an FTDI UM245R USB-parallel breakout board.
When I bought the board I knew very little about USB and I thought it would be similar to the USB parallel interface. If I was buying again I think I would get a UM232 board (which can also do parallel bit banging).
I don't know how fast it would be possible to read the ADC (I think the max I tried was about 1msps) but I think the limit is just whatever the USB system imposes.
My DSO board has a clock to trigger the samples and the UM245R just sends all the bits direct to the PC for as many bytes as the PC software requested.
You could probably use a similar arrangement to feed data into a RPI or BeagleBone.
Gathering 12-bit samples might be more complex than 8-bit samples because you have to collect 2 bytes for every sample - or do some complex stuff to collect 3 nibbles. At 5msps that would require some clever electronics.
...R
Thanks, 2 bytes is fine, or I could use an 8-bit ADC and gather 2 samples per source and multiply by 256 pc-side and average them for.
Anyway, the project is designed to be connected to a PC at some stage, not a stand alone device, so that is also worth looking into.