Parsko,
The tags read fine with the Parallax RFID reader. I sold the tags to Parallax and I tried them and sent some to Parallax for testing, and they read them fine. And the first project in my upcoming Propeller Projects Book 1 starts with an RFID project that controls a relay. A good start for controlling your house.
So, it was the first time I've hit F10 in a LONG time! It felt REALLY good!!! REALLY good! All my parts/boards were all over the place, and nothing was connected. Once connected, though, everything worked!
Parsko said...
Keep in mind, that I have tried this on 3 different sets of code, with 2 different RFID readers. So, I'm not fully convinced it is my code. Hence needing a known good tag...
I finally have "known good tags", and I was able to see the tag numbers!!! WooHoo!!! That was a huge relief for me and this project. I tried every Demo RFID code I had to see them all work with the tags, and most worked. There were problems with outputting HEX characters, but I recognize this, and it should be easily overcome once I get another chance to code.
Quick tangent: I'm not sure if my ma-in-law missed a piece of paper, but the RFID tags I recieved from Parallax did not have the tag ID's written anywhere... If I didn't have working code to retrieve them, then I wouldn't know what they were. Was this a problem on our end, or Parallax' end, I don't know?
Results:
The acquisition distance for the Keyfobs was around 2 inches. I'll try to get better numbers next time, and also use my other reader to check if there is a difference. The acquisition distance for the Glass tag was less than 1/2". (This tag is similar to the ones that are in my cats) I also observed that the orientation of the Glass tag w.r.t. the reader antenna made a HUGE difference, which I can understand. If I brought the tag down towards the reader parallel to the antenna lines, the tag would not read, even sitting directly on the reader. This makes sense because the antenna needs to create a field for the Glass tag to pick up, yadda yadda... It seemed to work best at the corners, where there are three non-collinear lines of the antenna intersecting. All the tags worked best at the corners, again, this makes sense.
I did not have any cats present during my follies last night, so I could not check on them. But, I feel fairly confident saying that I should be able to read the tags in my cats with this reader, but I don't think it will work. The capture range for the Glass tags is simply too small. This might explain why I never got it to work before. But, armed with my newfound knowledge that I should try using the corners of the reader, I may be able to get something.
But, with that evidence, I don't think the Parallax reader with work with my project. I do think that this concept will eventually work, but I need a stronger antenna. Unfortunately, designing this is way out of my league. I may try the setup from one of the links in my previous posts, it says the capture range should be longer, but the apparatus is not very pretty.
If anyone has any suggestions, at this point, how I should proceed, I'd love to hear them. I'd also be interested if someone could assist me in doing some of the research to get a better (stronger) antenna to use on the Parallax reader (aka to replace the antenna on the Parallax reader, but re-use the IC's). The capture range would need to be at least 4 inches (a little more than half the width of my largest cat), and it would be nice if the antenna was around 6 inches x 6 inches, so the cats could rub against it with a near 100% read success rate. I'm not sure if I mentioned before that I would like the antenna to be mounted behind a thin piece of carpet on the wall, about cat shoulder height, about 1 foot away from the cat door (or other cat device).
Quick summary:
- Hardware works with known good tags
- Keyfob reading distance: ~2 inches
- Glass fob reading distance: <1/2 inch
- Glass fob orientation critical to proper reading
I have the RFID reader attached to a Prop, and it readers the tags nicely, BUT I've never been able to get anything from my cats (RFID, or anything come to think of it... Might be frequency, nut I suspect range is a factor.
I did some theoretical calculations last night based upon the 4095 datasheet. You can see my results in the attached PDF. I think I should be able to get the 4095 to work on my cats. I designed a new antenna, I just need to make up the circuit, then write the Prop code to read from the 4095. I think the Prop end of it should be relatively easy. It's just detecting the CLK signal, then checking the state of the DE_MOD_out pin, pretty straightforward.
Without knowing what is used on the Parallax reader (without destructing it), I have concluded that my circuit can be changed to work with the 125kHz Tags by changing Cres1 from 1nF to 4.7nF. It should still be within all other limits. Eventually, I may figure what you use on your reader. For now, I'm comfortable trying to "roll my own".
I still have no clue as to what the range of my circuit will be. I should get my hands on one of the official Home Again rice sized animal tags to test with to be sure.
As I said before, this is an ongoing project, so it may be a while before I can get my hands on parts and build...
-Parsko
PS - I'd certainly appreciate anyone who actually knows what they are doing to double check that I haven't missed something obvious.
I’m very interested in your RFID cat door project, as I try to build one myself.
I actually got it to work using a standard RFID receiver module connected to an ATMEL processor, which directly moves a WAYPOINT 150 servo (directly built into a ‘normal’ cat door, operating the lock). It works nicely but the problem is to increase the range to a point where the cat doesn’t have to rub its neck against the door to get detected (cats are hard to train .
I did some experiments with homemade antennae, but never got beyond some 10-12 cm (through air, not counting that the tag inside the cat will probably decrease the range).
I’m afraid that the limited power available inside the RFID tag to send back the answer to the door may just not be enough to go much further. For the cat door, we’d probably want some 20-30cm range, depending on where the tag is located (often the neck, I think). That is a lot for this size of tag.
Well, vacation has brought me some good fortune. I spent the day yesterday relaxing and playing with my toys...
The plan was to dismember, err, remove the EM4095 chip from one of my RFID readers. That happened successfully, and I mounted it to a surfboard. I rolled my own antenna using 0.2mm magnet wire I bought at the local electronics store. 40 turns. Not perfectly spaced, due to the wire being so small, and my hands being so shaky (the reason I'm not a doctor!). I completed the board with all the rest of the components.
My approach to my Propeller code: first write code to toggle the the SHD pin to set it to a transmit state. Observe the CLK pin to see if it changes when a tag is presented.
SUCCESS!!!!
It worked. I am quite happy and proud so far. If you see the pics attached, you can see the results on my TV. There is a sequence of "0's" for about two lines, then it toggles 1's and 0's until it goes back to only 0's. When there is no tag, the CLK pin will simply toggle as long as the SHD pin is low. When a tag is there, I get what you see. There is a distinct difference between a tag being there, and one not being there. This confirmed that my hardware is working. YIPPIE!!
I get the feeling that I can't read the CLK pin fast enough in SPIN, so the next step is a falling edge detector in ASSY. Not today though. I'm happy with what I have, and have confidence to move to the ASSY step.
I also confirmed reading distances. The same as reported with the Parallax reader so far. I plan to roll more antenna's now that I know I can. I hope to get the reading distance good enough to read my cats.
EDIT: I have posted my working code which includes the schematic I am using with this setup. END EDIT
Okay, been working on this on and off for the past few weeks. I'm having a problem reading DEMOD-OUT, or MODOUT, or pin 13 on the EM4095 chip. I can read and log the CLK pin without any problems. I cannot read the MOD pin. The datasheet says the test condition for the CLK pin is 10mA (I have attached snapshots of the important pieces of the EM4095 datasheet). It also says that the test condition for the MODOUT pin to be 1mA.
I have tried:
-direct wiring of EM4095 pin 13 to a Prop pin
-1k resistor in series between the EM4095 pin 13 and a Prop pin
No luck.
There is no suggestion of a pull-up or pull-down on the MODOUT pin.
I cannot read any changing signal. I do get one solid series of "1's" followed by "0's", but no changing Manchester (or equiv) coded signal on the pin. Last night I confirmed that I should be able to read something by scoping the pin while activating the EM4095. The MODOUT pin shows nothing without a tag, and DEFInately something when a tag is present, leading me to believe I should see something. The traces were around 0.2ms in length, which makes sense for a rate of around 9600Baud.
I think my issue is not enough current available.
I ask for advice regarding any ideas to get the signal into the Prop. I've thought about using a transistor, or maybe placing a diode in series to drop it 0.7V to 4.3V, maybe two would be good to get down to 3.6V? With no formal electrical engineering education, I'm at a bit of a loss right now...
Thanks,
-Parsko
PS - the code I used does not seem to be the issue. I have seen the same results regardless of code changes I make, leading me to believe the problem to be hardware related.
parsko said...
PS - the code I used does not seem to be the issue. I have seen the same results regardless of code changes I make, leading me to believe the problem to be hardware related.
Famous last words!!! After realizing how ignorant this statement was, I decided to go back through my code again, just to make sure I wasn't being a moron.
mov mod, #0
was the the ONE line of code that was killing me for the last two weeks. I'm now getting decent results, but I'm not quite so sure that the rest is perfect. I'll keep truckin...
-Parsko
PS - "mod" should have been, and is now, "data", the destination for all incoming 1's and 0's. Mod is the pin they are arriving on, can't make that 0!
Any updates on using RFID with Cats? I'm thinking the 1 to 3" range of the Parallax's reader, might not be enough. Though it would be great if it were possible to use it. I was thinking the Sparkfun ID-20 with Parallax's key RFID tags. It is possible to add external antenna to Parallax's reader, which would be nice so I could have them switchable, inside, outside. No exposure to weather, of the actual reader electronics. Is it possible to make the custom antenna work better for my application?
thanks for asking. No updates. Short story, I'm consumed trying to get a minimalist data acquisition setup on my brothers racecar. As soon as I get this installed (which I hope to have done within a few months) I will immediately start back-up on my RFID project. Why? I'm ROYALLY pissed that I have to clean litterboxes multiple times a week!!!
Yes, 1-3" range needs to be exceeded. ~3-4" would be acceptable, as my biggest cat is pretty big, but not much more than 6-8 inches wide.
Cat tags work on 134kHz, Parallax works on 125kHz. They don't mesh, I know for sure.
I haven't tried sparkfuns, but would guess that it won't work due to the frequency.
Yes, modifying the external antenna should work, but may not be necessary. Modifying the oscillating frequency (capacitor on the reader itself) may work, but I wasn't successful with that.
Yes, a custom antenna would be perfect. The route I was on, and will pick back up on when I get to it, was to remove the EM4095 chip from Parallax' reader, make my own circuit and antenna, and use the prop to read the output. This is the most flexible, but least economic. Making antenna's is pretty easy, decoding the output from the chip with the appropriate demodulation technique (PSK, etc...) is a bit harder.
I was on a good path but distracted by other things last summer (mainly moving back to the US!), so it all was put on hold. But, it holds priority, and I've thought extensively about the mechanics behind the complete litter box and feeder apparatii.
I have approached this with the specific goal of using the tag that is implanted in each of my cats. It would be fairly trivial to use a tag mounted on a collar, but my cats don't wear (or like) collars. If you go that route, you could be done in a matter of days, IMHO.
I just checked that other post from Joe Grand (thanks JOE!!!), and have seen that other dudes mod. Haven't tried it, but you're still stuck with 125kHz, which won't work with implanted pet tags. It WILL work, of course, with a collar tag quite well, I would think. If you do try it, please post your results!!!!
and product discription
"Description: This is a very simple to use RFID reader module. With a built in antenna, the only holdup is the 2mm pin spacing (breakout board available below). Power the module, hold up a card, and get a serial string output containing the unique ID of the card.
Features:
* 5V supply
* 125kHz read frequency
* EM4001 64-bit RFID tag compatible
* 9600bps TTL and RS232 output
* Magnetic stripe emulation output
* Read range of 200mm
Dimensions: 38x40x7mm"
which would give about 7.87401575 inches, and is out of stock.
I'll probably go the easier route, and attach the key tag to the collar or harness. Using an external antenna on the parallax reader, can I get similar range? Or something to work with a key tag around their neck?
I saw that while back. It's a very nice setup! That may be a better route if you need distance. My experiments yeilded about that same as has been posted elsewhere of around 3-4" with a keyfob bought from parallax. The glass tags were much shorter.
Parallax has a revision two of the reader, which according to Paul baker, has a better reading distance. I think they tuned the antenna better, or used tighter spec caps and resistors on the tuning circuit. I have not had the pleasure to play with this one, and both of my readers were the first rev.
If the tag is located under the head/chin/neck of the cat or dog, you may have a problem with your reading distance using the parallax set-up. BUT, it is totally worth a try.
That level of accuracy (7.87401575) is amusing to me!!!
Oh, also, I've been thinking of adding a separate reading antenna to my set-up too. I think this helps with reading distance.
The EM4095 used on the Parallax reader is, I think, capable of much larger distances. But, the specific Parallax design does not accomodate. My guess is due to cost/size relationship. It is for the hobbiest, and really good for dudes setting up keyless entries/time management for businesses!
Comments
The tags read fine with the Parallax RFID reader. I sold the tags to Parallax and I tried them and sent some to Parallax for testing, and they read them fine. And the first project in my upcoming Propeller Projects Book 1 starts with an RFID project that controls a relay. A good start for controlling your house.
Oliver
Well, my mother-in-law arrived yesterday morning with a suitcase full of baby clothes, and some RFID tags!!! She brought:
2x RFID Blue Eye Key Fob Tag
1x Glass RFID Tag
So, it was the first time I've hit F10 in a LONG time! It felt REALLY good!!! REALLY good! All my parts/boards were all over the place, and nothing was connected. Once connected, though, everything worked!
I finally have "known good tags", and I was able to see the tag numbers!!! WooHoo!!! That was a huge relief for me and this project. I tried every Demo RFID code I had to see them all work with the tags, and most worked. There were problems with outputting HEX characters, but I recognize this, and it should be easily overcome once I get another chance to code.
Quick tangent: I'm not sure if my ma-in-law missed a piece of paper, but the RFID tags I recieved from Parallax did not have the tag ID's written anywhere... If I didn't have working code to retrieve them, then I wouldn't know what they were. Was this a problem on our end, or Parallax' end, I don't know?
Results:
The acquisition distance for the Keyfobs was around 2 inches. I'll try to get better numbers next time, and also use my other reader to check if there is a difference. The acquisition distance for the Glass tag was less than 1/2". (This tag is similar to the ones that are in my cats) I also observed that the orientation of the Glass tag w.r.t. the reader antenna made a HUGE difference, which I can understand. If I brought the tag down towards the reader parallel to the antenna lines, the tag would not read, even sitting directly on the reader. This makes sense because the antenna needs to create a field for the Glass tag to pick up, yadda yadda... It seemed to work best at the corners, where there are three non-collinear lines of the antenna intersecting. All the tags worked best at the corners, again, this makes sense.
I did not have any cats present during my follies last night, so I could not check on them. But, I feel fairly confident saying that I should be able to read the tags in my cats with this reader, but I don't think it will work. The capture range for the Glass tags is simply too small. This might explain why I never got it to work before. But, armed with my newfound knowledge that I should try using the corners of the reader, I may be able to get something.
But, with that evidence, I don't think the Parallax reader with work with my project. I do think that this concept will eventually work, but I need a stronger antenna. Unfortunately, designing this is way out of my league. I may try the setup from one of the links in my previous posts, it says the capture range should be longer, but the apparatus is not very pretty.
If anyone has any suggestions, at this point, how I should proceed, I'd love to hear them. I'd also be interested if someone could assist me in doing some of the research to get a better (stronger) antenna to use on the Parallax reader (aka to replace the antenna on the Parallax reader, but re-use the IC's). The capture range would need to be at least 4 inches (a little more than half the width of my largest cat), and it would be nice if the antenna was around 6 inches x 6 inches, so the cats could rub against it with a near 100% read success rate. I'm not sure if I mentioned before that I would like the antenna to be mounted behind a thin piece of carpet on the wall, about cat shoulder height, about 1 foot away from the cat door (or other cat device).
Quick summary:
- Hardware works with known good tags
- Keyfob reading distance: ~2 inches
- Glass fob reading distance: <1/2 inch
- Glass fob orientation critical to proper reading
Okay, that was a mouthful.
-Parsko
Good luck,
Mike
Without knowing what is used on the Parallax reader (without destructing it), I have concluded that my circuit can be changed to work with the 125kHz Tags by changing Cres1 from 1nF to 4.7nF. It should still be within all other limits. Eventually, I may figure what you use on your reader. For now, I'm comfortable trying to "roll my own".
I still have no clue as to what the range of my circuit will be. I should get my hands on one of the official Home Again rice sized animal tags to test with to be sure.
As I said before, this is an ongoing project, so it may be a while before I can get my hands on parts and build...
-Parsko
PS - I'd certainly appreciate anyone who actually knows what they are doing to double check that I haven't missed something obvious.
I’m very interested in your RFID cat door project, as I try to build one myself.
I actually got it to work using a standard RFID receiver module connected to an ATMEL processor, which directly moves a WAYPOINT 150 servo (directly built into a ‘normal’ cat door, operating the lock). It works nicely but the problem is to increase the range to a point where the cat doesn’t have to rub its neck against the door to get detected (cats are hard to train
I did some experiments with homemade antennae, but never got beyond some 10-12 cm (through air, not counting that the tag inside the cat will probably decrease the range).
I’m afraid that the limited power available inside the RFID tag to send back the answer to the door may just not be enough to go much further. For the cat door, we’d probably want some 20-30cm range, depending on where the tag is located (often the neck, I think). That is a lot for this size of tag.
An interesting article on making your own antenna is here:
http://www.eng.tau.ac.il/~yash/kw-usenix06/index.html
There is also a New Zealand based forum where people discuss the problem:
http://tagged.kaos.gen.nz/showthread.php?t=323
(but they mainly implant the tags into themselves, yuk !).
I’d be very interested to hear about any success on increasing range with standard RFID tags used with cats!
Werner
Well, vacation has brought me some good fortune. I spent the day yesterday relaxing and playing with my toys...
The plan was to dismember, err, remove the EM4095 chip from one of my RFID readers. That happened successfully, and I mounted it to a surfboard. I rolled my own antenna using 0.2mm magnet wire I bought at the local electronics store. 40 turns. Not perfectly spaced, due to the wire being so small, and my hands being so shaky (the reason I'm not a doctor!). I completed the board with all the rest of the components.
My approach to my Propeller code: first write code to toggle the the SHD pin to set it to a transmit state. Observe the CLK pin to see if it changes when a tag is presented.
SUCCESS!!!!
It worked. I am quite happy and proud so far. If you see the pics attached, you can see the results on my TV. There is a sequence of "0's" for about two lines, then it toggles 1's and 0's until it goes back to only 0's. When there is no tag, the CLK pin will simply toggle as long as the SHD pin is low. When a tag is there, I get what you see. There is a distinct difference between a tag being there, and one not being there. This confirmed that my hardware is working. YIPPIE!!
I get the feeling that I can't read the CLK pin fast enough in SPIN, so the next step is a falling edge detector in ASSY. Not today though. I'm happy with what I have, and have confidence to move to the ASSY step.
I also confirmed reading distances. The same as reported with the Parallax reader so far. I plan to roll more antenna's now that I know I can. I hope to get the reading distance good enough to read my cats.
EDIT: I have posted my working code which includes the schematic I am using with this setup. END EDIT
Off to bed to make some more bed-head...
-Parsko
PS - Another link to a forum post regarding RFID I have commented on...
Okay, been working on this on and off for the past few weeks. I'm having a problem reading DEMOD-OUT, or MODOUT, or pin 13 on the EM4095 chip. I can read and log the CLK pin without any problems. I cannot read the MOD pin. The datasheet says the test condition for the CLK pin is 10mA (I have attached snapshots of the important pieces of the EM4095 datasheet). It also says that the test condition for the MODOUT pin to be 1mA.
I have tried:
-direct wiring of EM4095 pin 13 to a Prop pin
-1k resistor in series between the EM4095 pin 13 and a Prop pin
No luck.
There is no suggestion of a pull-up or pull-down on the MODOUT pin.
I cannot read any changing signal. I do get one solid series of "1's" followed by "0's", but no changing Manchester (or equiv) coded signal on the pin. Last night I confirmed that I should be able to read something by scoping the pin while activating the EM4095. The MODOUT pin shows nothing without a tag, and DEFInately something when a tag is present, leading me to believe I should see something. The traces were around 0.2ms in length, which makes sense for a rate of around 9600Baud.
I think my issue is not enough current available.
I ask for advice regarding any ideas to get the signal into the Prop. I've thought about using a transistor, or maybe placing a diode in series to drop it 0.7V to 4.3V, maybe two would be good to get down to 3.6V? With no formal electrical engineering education, I'm at a bit of a loss right now...
Thanks,
-Parsko
PS - the code I used does not seem to be the issue. I have seen the same results regardless of code changes I make, leading me to believe the problem to be hardware related.
Famous last words!!! After realizing how ignorant this statement was, I decided to go back through my code again, just to make sure I wasn't being a moron.
mov mod, #0was the the ONE line of code that was killing me for the last two weeks. I'm now getting decent results, but I'm not quite so sure that the rest is perfect. I'll keep truckin...
-Parsko
PS - "mod" should have been, and is now, "data", the destination for all incoming 1's and 0's. Mod is the pin they are arriving on, can't make that 0!
http://www.microchipcatflaps.co.uk/contact.htm
Which solves the problem for me - I guess I'll just buy one ...
Werner
Is there any US version?
external ant for parallax's RFID reader discussion http://forums.parallax.com/forums/default.aspx?f=5&m=260475&r=x
thanks for asking. No updates. Short story, I'm consumed trying to get a minimalist data acquisition setup on my brothers racecar. As soon as I get this installed (which I hope to have done within a few months) I will immediately start back-up on my RFID project. Why? I'm ROYALLY pissed that I have to clean litterboxes multiple times a week!!!
Yes, 1-3" range needs to be exceeded. ~3-4" would be acceptable, as my biggest cat is pretty big, but not much more than 6-8 inches wide.
Cat tags work on 134kHz, Parallax works on 125kHz. They don't mesh, I know for sure.
I haven't tried sparkfuns, but would guess that it won't work due to the frequency.
Yes, modifying the external antenna should work, but may not be necessary. Modifying the oscillating frequency (capacitor on the reader itself) may work, but I wasn't successful with that.
Yes, a custom antenna would be perfect. The route I was on, and will pick back up on when I get to it, was to remove the EM4095 chip from Parallax' reader, make my own circuit and antenna, and use the prop to read the output. This is the most flexible, but least economic. Making antenna's is pretty easy, decoding the output from the chip with the appropriate demodulation technique (PSK, etc...) is a bit harder.
I was on a good path but distracted by other things last summer (mainly moving back to the US!), so it all was put on hold. But, it holds priority, and I've thought extensively about the mechanics behind the complete litter box and feeder apparatii.
I have approached this with the specific goal of using the tag that is implanted in each of my cats. It would be fairly trivial to use a tag mounted on a collar, but my cats don't wear (or like) collars. If you go that route, you could be done in a matter of days, IMHO.
I just checked that other post from Joe Grand (thanks JOE!!!), and have seen that other dudes mod. Haven't tried it, but you're still stuck with 125kHz, which won't work with implanted pet tags. It WILL work, of course, with a collar tag quite well, I would think. If you do try it, please post your results!!!!
-Luke
http://www.sparkfun.com/commerce/product_info.php?products_id=8628
and product discription
"Description: This is a very simple to use RFID reader module. With a built in antenna, the only holdup is the 2mm pin spacing (breakout board available below). Power the module, hold up a card, and get a serial string output containing the unique ID of the card.
Features:
* 5V supply
* 125kHz read frequency
* EM4001 64-bit RFID tag compatible
* 9600bps TTL and RS232 output
* Magnetic stripe emulation output
* Read range of 200mm
Dimensions: 38x40x7mm"
which would give about 7.87401575 inches, and is out of stock.
I'll probably go the easier route, and attach the key tag to the collar or harness. Using an external antenna on the parallax reader, can I get similar range? Or something to work with a key tag around their neck?
Parallax has a revision two of the reader, which according to Paul baker, has a better reading distance. I think they tuned the antenna better, or used tighter spec caps and resistors on the tuning circuit. I have not had the pleasure to play with this one, and both of my readers were the first rev.
If the tag is located under the head/chin/neck of the cat or dog, you may have a problem with your reading distance using the parallax set-up. BUT, it is totally worth a try.
That level of accuracy (7.87401575) is amusing to me!!!
Oh, also, I've been thinking of adding a separate reading antenna to my set-up too. I think this helps with reading distance.
The EM4095 used on the Parallax reader is, I think, capable of much larger distances. But, the specific Parallax design does not accomodate. My guess is due to cost/size relationship. It is for the hobbiest, and really good for dudes setting up keyless entries/time management for businesses!
-Luke