RFID application control

Evening guys n gals,

first post, so be gentle, after searching through the forums, I still can't seem to find any information on what I'm trying to do, if it's even possible.

This is an outline of what I'm trying to achieve.

I have on order an UNO, and also a couple of RFiD shields, one is a parallax USB model, what I'm attempting to do is use RFiD tags to launch applications on my pc based on what tag I have on my desktop, I keep notebooks for various projects, one for photography, one for web design, etc, and I'm aiming to have my pc load for example Photoshop when I place the photo editing notebook on my desk, then shut it down when I remove it.

I've got the sketches ready for the UNO to read across the com port and a small VB app I found on here to read the tags, my VB is very very rusty, i think i can do the if tag blah blah = photo then shell execute.. BUT it's so vague its' unreal lol and making the applications quit when I remove the notebook im completly stumped on.

If anyone has any idea, links to similar posts, etc that might be useful, then I'd be eternally grateful!

cheers peeps :slight_smile: x

and also a couple of RFiD shields

Links?

Typically, the RFID reader reads a tag when it comes in range, and does nothing when it goes out of range. So, your idea of doing something when the tag goes out of range will not work.

I've got the sketches ready for the UNO to read across the com port and a small VB app I found on here to read the tags

You've got this backwards. The Arduino will read the tag and write to the COM (serial) port. The VB app will read from the COM port, and compare tags, and do something when a match is found.

BUT it's so vague its' unreal

That's VB for you.

making the applications quit when I remove the notebook im completly stumped on.

Fortunately, Windows IS a multitasking system, AND it does provide a mechanism for you to close an application with a single mouse click.

I understand the basics of RFiD, in that once a tag is read it does nothing, surely there is a way to poll the reader every second say to check if either the tag has vanished or changed, and if so react accordingly. obviously a delay would be needed incase the notebook moved or something, but if no tag then it closes the last application opened.

I'd like to further this idea, and this is where the simple mouse click to close wouldn't be of any use. You see I have a pc under my tv, it serves to purposes.. to connects a remote desktop connection atm to my desktop to watch downloaded movies, iplayer and such, and play a fireplace video. My idea is I have some crystal pyramids, as ornaments, there's 6 in total on the coffee table, I had the idea of attaching a stiky rfid tag to the bottom, and say have the red one load the fireplace video fullscreen, the blue one load the rd connection to desktop, the others could load other applications.

I guess I could have it so vb polls the sensor, if after 60 seconds it finds no tag, it kills all applications running and loads the fireplace video.

it's getting vb to kill only the application I've loaded with the pyramid before hand.

sorry, my explanation of the arduino uno was a bit vague. I have a sketch which will read the tag and forward it to the serial port ready for vb to interact with it.

http://www.parallax.com/tabid/768/ProductID/517/Default.aspx > usb model
http://www.parallax.com/Store/Accessories/CommunicationRF/tabid/161/CategoryID/36/List/0/SortField/0/Level/a/ProductID/114/Default.aspx > serial one for UNO

the vb code reads a com port, so it doesn't matter if I do it with the USB one or the arduino one, the usb would probably be easier, as it's a little overkill using a UNO just to act as a middle man.

:S any clearer?? :blush:

surely there is a way to poll the reader every second say to check if either the tag has vanished or changed

Well, you might try the Wishful thinking" forum. Unfortunately, wishing won't affect the hardware.

I guess I could have it so vb polls the sensor

Are you attaching the RFID reader to the Arduino or to the PC? If you are attaching it to the Arduino, VB can't poll it. Period. End of story.

If you are attaching it to the PC, why are you asking questions here?

Gee, thankyou SO much for all your help my friend, it's sure nice to see friendly & helpful people still exist in this world.

Sorry, maybe I should have posted that in the Wishful Thinking forum??

I'm posting it in "this" forum because I'd like to use an arduino in my project.

Thanks tho, I'll figure it out myself, i've seen more complex things done with less, nothing's impossible.. not with a little imagination!

not with a little imagination!

And a willingness to build your own hardware. If you want to use existing hardware, you must be willing to work within it's design parameters.

Of course, I do not wish to deter you. I'm simply pointing out the limitations of the hardware that you have selected. In any case, good luck with your project.

I've got a small sketch that reads RFID cards (to open a door) here:

I'm not quite sure how that would start apps, but I suppose if you had some app on the PC that looked for data from the Arduino it could do so. Although you could probably connect the RFID reader directly to the PC via a FTDI cable and bypass the Arduino altogether.

As for removing the tag, short of seeing the spec, I'm inclined to agree with Paul. They generate a "read" when you move the tag towards them. As far as I know, there isn't a way of knowing if the tag is still there, but of course some readers might support just that.

...

The spec says:

To avoid treating spurious responses as legitimate tags, it is recommended to read two responses in a row within a given amount of time (for example, one second) to ensure that you are reading a valid tag and not a “tag” generated by noise.

So there is a bit of an implication there that the same tag might generate multiple reads. Maybe some testing ...

However you might also consider a weight (pressure) sensor, so that when the device is removed the weight goes down. Or some kind of light beam. Or some magnetic tag that activates a Hall effect sensor.