Is there any way to determine the format of an unknown data stream

rjenkinsgb said:

I've spent a couple of hours working through those displays & values, but nothing definite yet.

Click to expand...

I'm feeling a little guilty here, seeing how much time you've spent on this. I appreciate it very much ... thank you.

rjenkinsgb said:

One has a lot of correlation between the data and the hex value - but reading the other in the same way has next to none...

Click to expand...

I was amazed when you found any ... I'd just seen it as an impossible task.

rjenkinsgb said:

What are the decimal numbers visible around the tags in one of the early pictures - are they the same things you are reading? The numbers you give do not seem to match that format.

Click to expand...

I didn't take note of the tag I used in the first image ... but I only have 3 of them.

If the first image wasn't from either of the tags listed in the second lot of photos ... it would be from #3 ... DEC 116153294


When I did that second lot of photos and noted the numbers, I was very careful to match images with their particular tag ... so I'm 100% certain I didn't mix them up ... in fact I left the 3rd tag in the bag just to avoid that possibility.


One thing that I did wonder about ... on some tag readers, the decimal number has 3 leading 0's ... but on others it doesn't ... so I'm hoping that might not be the cause for confusion. I should have mentioned that earlier ... but I have always assumed it was because of the format of the particular reader and not the tag.

I don't seem to recall extra 0's associated with the HEX number that some other readers display.


Even if we can't work out how to read tags on this particular system atm ... the discussion has opened my eyes to the prospect of using a logic analyzer to investigate further.

Nigel Goodwin said:

Bear in mind you can buy very cheap USB logic analysers, like this one:

https://www.banggood.com/USB-Logic-...M-FPGA-Debug-Tool-p-1177821.html?rmmds=search

Which will far out perform the PK2, which only has a very small memory buffer - but is still a VERY useful feature.

Click to expand...

Thanks for the heads up. It's just a pity I have a PICkit 3 and not a PICkit 2 otherwise I could have continued on staight away.

If I'm going to buy an analyzer, I might as well get one that will do as much as possible ... especially as they are so cheap. It's really only the delivery time factor for us out here in Australia that slows things down.

I've already sent the first of the 2 tag readers back to its owner ... and need to send the other back within days ... so could be weeks or months before I have another one in front of me to experiment more.

Of course there are heaps of other brands I see that I have the same issue with ... so I can't wait to get an analyzer to investigate them as well.

rjenkinsgb said:

Those little logic analyzers look interesting!

A quick search on ebay turns up places in the UK selling them at around the same price, eg.
**broken link removed**

Also some rather faster ones, though priced to match the performance...
**broken link removed**

Click to expand...

Yeah ... I'd already gone down that track. There are some of the 2nd type available at around $100 AUD ... so I'll do a little more investigation and probably go for something like that.

Now that I've watched a couple videos of techs using them ... I can see more uses in my line of work as well.


Thanks JonSea for suggesting analyzers in the first place.