Design files

[JVKran]

Hi @Gerriko!

Thanks for opening up your design to the world. We're keen to incorporate your design in one of our PCB's and hence would like to ask you if you're open to adding the design files (Fusion/Kicad/Altium) to the repository.

Also we were wondering what detection distance you manage to reach. With the Elechouse module, we're reaching about 7-8 centimeters.

Kind regards,

Jochem

[Gerriko]

It was designed in EasyEDA. I haven't done so as yet, but I could share it on https://oshwlab.com/ if that helps.

I wouldn't say my tests using my hand soldered test boards were quite that good. It's quite an art form getting the antenna tuning and the matching circuit nicely balanced.

[JVKran]

Hi Gerriko, that would be great. It's quite an art indeed. Can you be a little more precise on what distance you managed to accomplish? Something in the ballpark of 5/6cm would be more than enough.

[Gerriko]

Hi @JVKran I cannot remember the distance, to be honest. I recall that I was a little disappointed with the result. At the time the only other option I had used was the OM5578/PN7150ARDM evaluation board.

Anyway, as the circuit design is over 4 years old now, and quite a bit has changed in EasyEDA since then so I am having to update. Of course, when revisiting the design I spot little things that can be tweaked. Hence the delay.

[nitz]

I'm glad to see you're looking at this again, @Gerriko! RF design is (and remains) to me personally a dark magic that I don't think I'll ever grok. But I did want to point you at NXP's Antenna Design Tool in case you hadn't seen it like I had when I started playing with laying out my own. It's supposed to help with the matching circuit and the coiling.

I look forward to seeing future revisions of your work! 😄

[Gerriko]

@nitz thanks for the links. Yes, I would have used that tool and the one from STMicroelectronics to design my antenna. Theory and what you get in reality can be quite different, as demonstrated.

(also for @JVKran) here is a quick video I just took showing the distance achieved with my first version. It's about 4cm range. As you can see it is not the best but I'm positive I'll get an improvement with my next version.

https://www.youtube.com/shorts/2LVh4NLmkVE

For my next version, I've decided to go with an off-the-shelf antenna using a twisted pair cable and connector (thus doing away with the PCB antenna). I've found that these type of adhesive backed antennae are so much cheaper now, and are more versatile IMHO. I've used with an MFRC522 module and they are good. Unfortunately, I have not found those design tools from NXP and STM are not tailored for this sort of thing so it may take a few iterations. Watch this space.

[JVKran]

Hi @Gerriko!

As well as @nitz, I'm glad to see you making progress on this! The video is looking good; thanks for that. I'm keen on keeping track of what you manage to come up with regarding the off-the-shelf antenna.

Can you give an example of such an antenna? How long are the wires for example to the coil?

Good luck! 😄