rfid with more than 10cm distance. does it exists ?

[snowman]

Dear friends,

I needed to build a cat door with arduino.I searched rfid shields butthat work from 10cm distance which is too small. then I looked after other rfid reader/tag solutions not for arduino, and I could not find anything. I know that rfid technology is close range technology but I cannot attach a heavy and large object that includes batteries onto cat's collar. there are these kind ofsolutions for dogs but they are mush more powerfull than cats.

any suggestions about which kind of technology should I use ? I guess minimum 25-30 cm would be required to sense the "specific cat with collar".

thanks.

[bigtoy]

Doing a google search for "long range rfid" produces many potentially interesting results (plus lots of junk :-) ). This forum discussion was  interesting:

http://forums.parallax.com/showthread.php/148222-Long-range-RFID

[marianqt]

Hello AykutCanturk,
It think is not necessary the "20-30 cm" distance to read the tag.
Look at here:  http://www.sureflap.com/products/details/1-microchip-cat-door
On the page you will find a good video about how it works.
On the other hand, speaking about the collar, i think it is not a really good ideea(A good friend of mine found his cat suffocated).
I think the better ideea remain the tag for pets under the skin.
For the protocol involved maybe help you this page: http://en.wikipedia.org/wiki/ISO_11784_%26_11785
Good luck with the project!

[Parmin]

RFID come in 2 flavor.

Powered model (eg. tag cards for toll motor ways) and parasitic powered model (the common RIFD tags)

Powered model can go up to 20 meters or more.
Parasitic power model distance is depended on the antenna and sensitivity of the reader.
You can get a good quality reader with largish antenna (1 square foot in size) to be able to read up to 1 meter.

[solutions]

Too complicated for the basic functionality you are after.

Why not a permanent magnet on the cat collar and a flux gate magnetometer at the door? You want cat vs raccoon, or cat with magnet vs other cat without, not cat with certain serial number getting through

[Parmin]

Damn solutions, why do you have to go all logical in this?

I like a better and improved mouse trap..

[snowman]

Too complicated for the basic functionality you are after.

Why not a permanent magnet on the cat collar and a flux gate magnetometer at the door? You want cat vs raccoon, or cat with magnet vs other cat without, not cat with certain serial number getting through

oh my god... I already have hall sensors I got for my cnc.. this was brilliant. also I have small neodium magnets in small rectangular shapes, thay are light weight. also I can use multiple hall effect sensors... blah blah...

you're the man my friend, thank you....

[solutions]

Hall sensors are not sensitive enough unless you have a REALLY smart cat.

Think compass (flux gate magnetometer). Some of the robot shops/suppliers have them....I think even Lego does.

There you go - build it on NXT, LOL

Posted on: July 02, 2013, 01:52:33 13:52 - Automerged
This might work: https://www.sparkfun.com/products/7915

Posted on: July 02, 2013, 01:59:03 13:59 - Automerged
or this http://www.trossenrobotics.com/p/grove-3-axis-compass.aspx

Posted on: July 02, 2013, 02:02:40 14:02 - Automerged
or Lego NXT if you have bags of money: http://www.hitechnic.com/cgi-bin/commerce.cgi?preadd=action&key=NMC1034

[Catcatcat]

Long-range systems are designed with an operating frequency of 13.56 MHz and 2.4 GHz

[snowman]

hmm, right, hall sensors require educated smart cats who can almost use keyboard

compass solutions look good as they can also be used as magnetometer.

I need to order one and wait for it. by the way, cat should wait for home residents to open doors

[bobcat1]

Hi

UHF RF-ID tags can work for long distance up several meters away

I think MURATA has several modules how use UHF RF-ID , but you can always search Google for better result

All the best

Bobi

[card_claud]

How about another type of RF link, NRF24L01 has support for arduino as well.

[Checksum8]

Using Solution's idea. Here's a LM555 magnetometer. Simple to build. I made one using a 5v reed relay coil from radio shack. The only trick is to make a frequency change detector. Maybe another 555 as a missing pulse detector, a dedicated F to V convertor or a micro monitoring the freq.?

http://www.youtube.com/watch?v=dP84iJlQCDI

[Ichan]

Thinking the other way around: Train your cat to open it's own door...  .

Here is a video cat opening 5 normal door in sequence to go outside the house:

http://www.youtube.com/watch?v=nLR9HDHInGM

-ichan

[solutions]

Using Solution's idea. Here's a LM555 magnetometer. Simple to build. I made one using a 5v reed relay coil from radio shack. The only trick is to make a frequency change detector. Maybe another 555 as a missing pulse detector, a dedicated F to V convertor or a micro monitoring the freq.?

http://www.youtube.com/watch?v=dP84iJlQCDI

So much for the originality of my idea:

[bigtoy]

I must hand it to solutions - that was a good idea.

[zac]

Yes, greater than 10 cm (4") is possible with passive (non-powered) RFID.  Much longer ranges are possible with powered RFID transponders such as used for toll bridges (fastrak, etc.).  There are commercial dog dogs using passive RFID tags that claim a 12-15" range:

http://www.plexidors.com/electronic_units.php

These RFID keys have no internal power source and obtains its power, inductively coupled, from a sizable coil.   I think these particular ones operate at 125 khz.  

[David_1]

but wont his cat already have a tag inside it

[eidtech]

Use Low Frequency Tags, i reached up to 3 meters with LF (134 Khz). I recommend Texas Instruments (TIRIS).

It is a common mistake to think greater frequency, greater read range.

Readers are very simple, you can build a reader with only a MCU. Check Elektor Magazine (October 2005).

[zac]

Use Low Frequency Tags, i reached up to 3 meters with LF (134 Khz). I recommend Texas Instruments (TIRIS).

Is that with a powered RFID transponder?

[eidtech]

No. It is passive. No internal power source.

Look for TIRIS Low Frequency

[zac]

No. It is passive. No internal power source.

Look for TIRIS Low Frequency

Do you have a link?  I'm very curious as I was looking for a longer range passive RFID system.  The antenna had to be a reasonable size (<1' wide) and the RFID tag had to be <1.5" wide (preferably smaller). 

To get 3M (~10') range with a passive RFID tag, it seems a very large antenna and a high RF field strength would be required. 

[2N5109]

One passive method that has been used is a simple anti parallel diode pair across two antennas, one resonant at Fo and the other at 2*Fo.  You transmit to the tag at Fo and receive the 2Fo frequency with a selective receiver.  You can see how you can easily build up dynamic range by filtering since the frequencies are widely spaced.  Even though the radiated 2*Fo signal is very weak you know exactly what its phase is so you can detect it in noise.  You can use cosite interference cancellation techniques to further improve the system. This technique has been used to obtain much greater than 10 cm range. 

--2N5109

[snowman]

I got my 3 axis magnetometer for arduino for 5 dollars or something, connected to arduino with 4 wires and its fantastic. first tests with neodium magnet which is 1cmx4mmx3mm show that this sensor can actually sense magnetic fields from more than 1 meter. but I didn't develop an algorithm that calculates a kind of average value for all 3 axises which has to be done. but I can definitely say that if you hold magnet in a distance of 1 meter and change the direction of magnet which means you change the poles of magnet, you can see the results on computer screen. but reading values are changing all the time, they are not stable maybe because of other electronic devices around, that's why I need a average calculation algorithm over 3 axises.

[zac]

I got my 3 axis magnetometer for arduino for 5 dollars or something, connected to arduino with 4 wires and its fantastic. first tests with neodium magnet which is 1cmx4mmx3mm show that this sensor can actually sense magnetic fields from more than 1 meter. but I didn't develop an algorithm that calculates a kind of average value for all 3 axises which has to be done. but I can definitely say that if you hold magnet in a distance of 1 meter and change the direction of magnet which means you change the poles of magnet, you can see the results on computer screen. but reading values are changing all the time, they are not stable maybe because of other electronic devices around, that's why I need a average calculation algorithm over 3 axises.

So, that uses something like this?

http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Defense_Brochures-documents/HMC5883L_3-Axis_Digital_Compass_IC.pdf

And that can detect the magnetic field from a small rare earth permanent magnet from more than a meter away?  I would be very curious to see a plot of the readings as the magnet approaches the sensor starting from a couple meters away.