Digital Storage Ocilloscope with Arduino/LabVIEW

[ptv]

Hi everyone,

I am kinda new to both LabVIEW and the Arduino, I've been trying the examples available and I think I'm understanding somewhat how they work.

My project uses the Arduino Uno board along with the SD shield, I sample an input signal from an oscilloscope and I save the sampled 10-bit integer values on a text file on my SD card. I would like to use LabVIEW to display the output, hoping that I will be avoiding some trouble since that way I don't have to use an DAC to ouput the waveform on an oscilloscope.

• I've been reading that LabVIEW can export measurements to an EXCEL file (could .txt work?), but could it be possible that a VI reads the values from the card and ouputs them by using a Waveform chart?
  

Any help that points me in the right direction will be appreciated. Thanks!

Pavel

[Kristoff2]

Pavel,

You can certainly use LabVIEW to display your data on a waveform graph, save it to excel, a text file, TDMS file, binary file, or almost any other file format you can think of.  I assume you are not using a file system on the SD card (eg FAT16, FAT32, ...) but are instead just writing blocks or bytes at a time. 

If this is the case you can modify the LIFA firmware to add a command that requests a byte or block from the SD card by address.  The way I see it working is:

Create a Read SD Card vi that send a request to the arduino containing the mode: block or byte, and the address.

The arduino receives the command, reads from the SD card and returns the data.

LabVIEW will receive a string and can be converted to a byte array and then reassembled into useful data (eg bitshifting to get 10-bit numbers again).

From here you could write the array to any sort of file you like or display it on a waveform graph.

Let us know if you have any quesions about how this might work.

-Sam K

LIFA Developer

[ptv]

Hi Sam,

The signal I need to sample is a 1MHz sine wave, since the arduino's adc isn't fast enough, i am using an external adc and then sending its ouput to the sd card through a digital pin on the arduino.  After the samples are stored in the SD card in a text file, I want to send them to labview and plot them with the appropiate frequency and amplitude as the original input signal.

You mentioned previously this

"If this is the case you can modify the LIFA firmware to add a command that requests a byte or block from the SD card by address.  The way I see it working is:

Create a Read SD Card vi that send a request to the arduino containing the mode: block or byte, and the address.

The arduino receives the command, reads from the SD card and returns the data.

LabVIEW will receive a string and can be converted to a byte array and then reassembled into useful data (eg bitshifting to get 10-bit numbers again)."

Could you please guide through these steps by giving some examples? I need to take baby steps to understand the process.

I really appreciate any help. Thanks!

Pavel