# Build RFID antenna for range 0.5m-1m **URL:** \ **Category:** General Guidance\ **Created:** [April 19, 2018, 10:59am UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232 "2018-04-19T10:59:52Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![darrell\_winfield](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@darrell\_winfield](https://forum.arduino.cc/u/darrell_winfield)\ **Post date:** [April 19, 2018, 10:59am UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/1 "2018-04-19T10:59:52Z")
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=199983.0) [https://forum.arduino.cc/index.php?topic=326640.0](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](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: > **[125Khz RFID module - UART](https://www.seeedstudio.com/125Khz-RFID-module-UART.html)** > > effective distance: 50mm Less than 100ms decoding time UART TTL interface OR > **[Grove - 125KHz RFID Reader](https://www.seeedstudio.com/Grove-125KHz-RFID-Reader.html)** > > This Grove-125KHz RFID Reader is a module used to read uem4100 RFID card information. 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? ---
**Author:** ![JohnLincoln](https://avatars.discourse-cdn.com/v4/letter/j/7ba0ec/32.png) [@JohnLincoln](https://forum.arduino.cc/u/JohnLincoln)\ **Post date:** [April 19, 2018, 11:38am UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/2 "2018-04-19T11:38:55Z")
If you look at this [Application Note](http://ww1.microchip.com/downloads/en/AppNotes/00710c.pdf) 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. ---
**Author:** ![darrell\_winfield](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@darrell\_winfield](https://forum.arduino.cc/u/darrell_winfield)\ **Post date:** [April 19, 2018, 12:58pm UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/3 "2018-04-19T12:58:34Z")
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: > **[RFID coil antenna](https://www.priority1design.com.au/rfid_coil_antenna.html)** > > rfid coil antenna, we carry stock of various rfid coil antennas as we use them in our rfid reader products 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? ---
**Author:** ![rjrapid5150](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@rjrapid5150](https://forum.arduino.cc/u/rjrapid5150)\ **Post date:** [January 20, 2019, 5:34pm UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/4 "2019-01-20T17:34:07Z")
I am attempting to build a very similar project, have you figured anything out? darrell\_winfield ---
**Author:** ![Paul\_KD7HB](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/paul_kd7hb/32/1127958_2.png) [@Paul\_KD7HB](https://forum.arduino.cc/u/Paul_KD7HB)\ **Post date:** [January 20, 2019, 7:04pm UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/5 "2019-01-20T19:04:58Z")
> 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 ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [May 5, 2021, 6:33pm UTC](https://forum.arduino.cc/t/build-rfid-antenna-for-range-0-5m-1m/521232/6 "2021-05-05T18:33:05Z")