I have 125KHz RFID Reader. Why does it fail to read more than one tag at a time? How can I program it for reading multiple tags? Is it possible to add an anticollision protocol there?
You are probably not using a reader and tag that is capable of anti-collision protocol. Without that capability the tags answer at the same time and interfere with each other's signals.
Anti-collision is not common with LF RFID.
Related
This is a somewhat theoretical question that risk being downvoted.
It would, however, be of great help, if answered, e.g. in cases of UI translation/localization.
What (if any) is the substantial difference in meaning between codec and protocol?
(Communications) Protocol
A Communications protocol defines in what manner two systems can communicate. It is not an actual program.
One could loosely compare a protocol to an interface as used in e.g. Java and C#. It defines how you are able to "speak" with an object that is an instance of a class that implements said interface. An example of a protocol is the Transmission Control Protocol (TCP) which, among other things, defines the format of each message sent over a network link.
Codec (encoder/decoder)
A codec, in the most general sense, is a program that is able to convert data to and from a set of specific formats, e.g. from the format that a video file is encoded on disk to a format that is understood by the graphics stack provided by the OS/kernel. FFmpeg, for example, contains a number of codecs to be able to play a wide variety of audio and video files.
I need to do some NON-STANDARD signal processing operations with an RFID-reader, so I'd like to know if it is possible to extract antenna's individual analog (actually digital samples right after ADC) input signal samples with Motorola FX7500 (if you know how this works on FX7400 or FX9500, please do tell, could be helpful). Samples would be processed in a JAVA-based host computer program.
What I've already tried:
Investigating Motorola's own RFID3 API's possibilities, it doesn't go deep enough to actually get in touch with input analog signal samples.
Using LLRP to its full extent, it doesn't allow analog signal sample access either. RFsurvey-functionality would have been helpful to some extent, but FX7500 doesn't support it either.
Accessing RFID-reader's linux terminal, trying to find the driver function(s), that could listen the input sample stream. If current input sample(s) could be extracted from the input stream, I could (in theory) make a script, that would save a few of those sample values in a txt-file in the host computer during a tag inventory round. My linux skills are kinda bad, hence I ask this question.
The only realistic way to solution seems to be via linux terminal, so if you folks have any ideas about that (where to look and what to do), please advise!
Contents of reader:
rfidadm#FX7500abcdef:/$ ls -1
apps
bin
dev
etc
home
include
lib
linuxrc
media
mnt
platform
proc
readerconfig
run
sbin
sys
tmp
usr
var
I cannot completely rule that out, but it's highly unlikely you can get the raw signal digitized; the devices you're looking at aren't really software defined radio devices, typically.
"speaking" RFID physically is a bit different from "usual" wireless communication: The reader doesn't only observe the energy transmitted from the tag, but more importantly the fluctuations of energy extracted from the near field of the reader's antenna coil. Hence, you don't actually have a baseband of RF bandpass signal, but hardware-specific modulations of transmitted (and inversely, antenna-reflected) energy. Demodulation is hence usually done in specialized hardware.
However, do not fret: It's totally possible to build a software defined RFID reader. There have been several approaches to that, but personally, I trust these based on Ettus USRPs and/or GNU Radio best. Look through the results IEEExplore gives you, eg. this search.
Most probably this is not possible with the Motorola readers. What you can do, is use one of the RFID chipsets available on the market: either the AMS RFID IC's, or the Impinj RFID IC's. As far as I know, both IC's support retrieving the digital samples that are received. They also have a development kit to test-drive the IC's.
I have been tasked to tag a video frame-by-frame with gps coordinates as it is recording.
The platform must be on Linux (Ubuntu to be specific).
Very new to programming with video sources..
Some questions :
Do video frames even have per-frame meta data?
Is GStreamer a good framework to use for my purposes? How should I get started?
Thanks.
Check GstMeta: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstMeta.html
It allows you to attach arbitrary metadata to buffers, which then can be passed downstream with the buffers and passed through other elements if possible. Take a look at the code of existing GstMeta implementations in gst-plugins-base for examples: http://cgit.freedesktop.org/gstreamer/gst-plugins-base/tree/gst-libs/gst/video/gstvideometa.h http://cgit.freedesktop.org/gstreamer/gst-plugins-base/tree/gst-libs/gst/video/gstvideometa.c
Your meta would probably work very similar to the region of interest meta (plain metadata)
To get started, read the documentation on http://gstreamer.freedesktop.org , especially start with the application writers manual. And take a look at existing GStreamer code to understand how everything works together.
I have an RFID reader which is ISO 14443A compliant. It is capable of reading Mifare 1k (s50), Mifare 4k (s70), and Mifare Mini (s20) cards. I want to know if the same RFID reader can read the cards which are ISO 15693 compliant. I am new with RFID and I dont know anything about the ISO standards.
Compliancy to ISO14443 does not imply compliancy to ISO15693. However, some reader chips can do both. If you can tell the model name of your reader, or the reader chip inside, it may be possible to tell whether it supports ISO15693.
Check with your reader manufacturer to see if it supports both protocols. Many do; but, you should double check to be sure.
Even if it does support both, it will likely NOT be able to do so simultaneously. Likely, you will have to toggle between the two protocols in order work with both types of RFID tags.
ISO14443 A/B and ISO15693 standard operate on the same frequency 13.56 MHz, and both have about the same read range when reading tags 5 - 20 cm, but from then on the similarities end.
They have different ways to access RFID tags and perform inventory, data read/write and different memory organization.
Because of the similarities some manufacturers provide readers that can handle both types of tags, but the procedure is different due to the different standards (so a software designed to read ISO14443 will not read ISO15693 and vice-versa).
As previous answers you will need to check with your manufacturer to be sure, but if you need a recommendation of reader with which I have worked you can try the IDTronic Desktop EVO HF or IDTronic Desktop EVO LEGIC. From my knowledge it's under 100 $.
Datasheet here:
Desktop EVO Reader Datasheet
the RFID reader ISO 14443A can not read the cards which are ISO 15693.
they are totally two different kind standard.
for rfid reader, i think you could first learn from this rfid news here http://syncotek.com/news/
I am writing software to parse ID3v2 tags in Java. I need to find some files with good examples of the tag with lots of different frames. Ideally the tags will contain an embedded picture because that is what is kicking my butt right now.
Does anyone know where I can find some good free (legal) ID3v2 tagged files (ID3v2.2 and ID3v2.3)?
You can create the example files with a tagger by yourself. I'm the author of the Windows freeware tagger Mp3tag which is able to write ID3v2.3 (UTF-16 and ISO-8859-1) and ID3v2.4 tags in UTF-8 (both along with APIC frames). You can find a list of supported frames here.
To create ID3v2.2 tags, I think the only program out there is iTunes which interpretes the ID3 spec in it's very own way and writes numerous iTunes specific frames that are not in the spec.
This maybe be obvious and not what you are seeking, but what about ripping some of your legally obtained CDs and editing them using iTunes? iTunes would also allow you to add embedded picture. There are of course many open source programs that will also do this.