Hello there! I am looking to do a project similar to what many people around here have been asking about, but I think I might be able to get better success because I am not constrained by size like everyone else:
https://forum.arduino.cc/index.php?topic=199983.0
https://forum.arduino.cc/index.php?topic=326640.0
etc.
Basically, I'm making a dog door and I want to be able to read the RFID a few feet out (not 100m like UHF and bluetooth ranges and prices) instead of a few inches. I've seen multiple people here say that it's possible, you just need a big enough antenna. I have the space for a big antenna. I've found one you can purchase:
http://chafonrfid.com/productdetails.aspx?pid=362
But it isn't very cheap and compatible.
So here's what I was thinking. I buy this:
OR
and build my own antenna instead out of magnetic wire.
So here are my questions:
First, is it possible to simply build my own antenna and have it work with the above RFID module?
Secondly, what do I need to be careful of when building the antenna? What are some common mistakes that people make that I should avoid? How many turns should I try to start?
Finally, what approximate diameter should I be looking at?
If you look at this Application Note about designing RFID antennas, then I think you will find that it is not trivial.
Manufacturers are able to spend many thousands of $/£/€ developing their antennas because they are expecting to sell so many. Designing a 1 off isn't going to be cost effective.
JohnLincoln,
From what I understand, the application note adds a mathematical aspect to the idea that a circular antenna needs to be coiled tightly and precisely inducted. So, while I could possibly create an antenna with the range I'm looking for, it wouldn't be easy and there would likely be a lot of wasted material/space.
With that in mind, do you know of any company that produces a big enough circular antenna for my purposes? I've found some companies like this one:
But even that isn't in my range.
On top of that, I can't help but think that even if I buy/make a large enough antenna, the chip/module powerful enough to drive it would be rather expensive/hard to find. Do you think that this would also be the case?
I am attempting to build a very similar project, have you figured anything out? darrell_winfield
rjrapid5150:
I am attempting to build a very similar project, have you figured anything out? darrell_winfield
Did you read in the link that their antenna is designed to be used with THEIR tags? That so-called antenna uses the magnetic field of the antenna to connect to the antenna in their tag at their design frequency.
Paul