Building Array of U8 to GrayScale out of Read Serial Visa

[JosephVictorWagieh]

Hello 

I'm facing troubles while building U8 array into Grayscale image through VISA READ from Arduino

 1st problem I built this VI to store an array of data (0-255) one dimension then reshapes it to the image size i want which is 120x160 but I cant connect it to the input of flatten pixmap.

2nd problem I used a delay to print each U8 so it will take time that might be 32mins to build the image  so can someone help me to get an easier way to build it faster? like taking multiple of U8 bytes in each loop instead of waiting that much ( i can't do it since i can only deal with one byte each )

[JLanzagorta · Accepted solution]

Hello Joseph,

Regarding your first problem, the reason why the wire gets broken is due to data type incompatibility. The U8 function takes a numeric input, while you are inputting a string input, therefore, you are getting your wire broken. In order to avoid this, you should convert your string input into a numeric input using any LabVIEW built-in function like Decimal String to Number.

In order to be able to answer your second question, could you share with us the next points:

1. Have you tried using some higher-level API (e.g.: Hobbyist Toolkit (previously known as LYNX) or LIFA) to link your Arduino? If so, weren't they useful to address your problem, or why are you using the low-level VISA API?
2. Could you elaborate a bit on how the VISA Read function represents the 3 bytes worth of data in the Read Buffer terminal for your specific device?

If any of the information above was useful at all, please kudos to my answer.

Best regards.

[billko]

How do you know if you are getting the correct three bytes, and not, say, two bytes from one value and one byte from the next one?

[JosephVictorWagieh]

Hello, thanks for helping me with my first problem , about the second one I'm sure I'm mistaken with the data type "3 byte" but as far as ik that I'm only able to see what is being written in via serial as " string" and max is 255 so I thought one byte represents each digit since I'm only sending pixel per pixel and here comes my problem it will be slow to build that 120*160 array that's why I asked if there a faster way to build it or a better way to send data and extract each pixel in one element in that array also the libraries you mentioned can't help me building the image

[daveTW · Accepted solution]

Hello Joseph,

first of all you should explain what kind of data is coming from your arduino. I suppose, you are programming the arduino firmware yourself, so you should be able to explain this.

To clarify the vocabulary I think, it could help you to read this:

https://forums.ni.com/t5/LabVIEW/Complete-String-Conversion-Tutorial/m-p/4245188

Some things to mention:

1. Your while loop never stops. What condition do you define to leave the loop?
2. How are you sure, you didn't miss data?
3. You could convert the received string data to the needed byte data in the loop right after receiving and build an array of bytes. Better performance, less memory consumption.

[daveTW]

Some more notes:

The "reshape array" function is very fast, so there is no performance issue at this point.

Place a probe at the array wire where the received values are stored and see whether the expected values are there.

To check the picture function, you could do something like this: