NFC antenna amplifier/Resonance Circuit project

Somedays im suprised the hospital let me leave with actual human beings i am responsible for… fixed.

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That’s awesome! Just out of curiosity, how thick is your desk? I would love to do that but I think mine is too thick even with the repeater

i considered for a brief moment adding an LED to the repeater sticker design we’re mass producing but thought better of it… no need to add power draw to something that has no noticeable draw, particularly for battery powered locks and devices.

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just shy of 3/4"

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Thanks! My desk that I made with an Ikea countertop is 1.5" (3.81cm) thick so I don’t think that’ll work :sweat_smile:

Wont know unless you try?

I was actually considering that Ikea Butcherblock top for a new desk. THis is just some cheapo amazon computer desk i bought mid pandemic because i didnt have a desk… or a computer…

True, true. I guess I’ll have to order a v2 to find out :stuck_out_tongue_winking_eye:

This coil is 816nH and I used online resonant frequency calculator to calculate the capacitor, the best value is 168.8pF but I don’t have that, so I chose 390pF and 300pF in series, and connect them to the coil.
And it works well, I also made a smaller one (25mm x 10mm) and it also works good.

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Yeah keeping the components to a minimum is probably ideal. There are other options though for the future :wink:

Some pretty fun stuff I can do with it haha

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I got something cool in the works with what I’ve learned from this project. But per usual I just need more useful hours in a day…

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So unfortunately my desk it too thick to place the reader beneath. However, I attached a repeater to each of my readers with gaffers tape and they work so much better! I can just set my arm anywhere on the reader and it works every time! No more worrying about getting the position right!

Also, the mini repeater preforms MUCH better on my flipper than the old version. It can read my NExT through the silicone case without touching my hand! :exploding_head: Can I order another smaller repeater for my other Flipper?

I am almost out of stock on the smaller prototype boards so I’ll have to do another order of them soon.

But I did get my first round of flex in and damn they are thin. Like thinner than paper thin.

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I have one of Hammy’s large repeater PCBs and placing the reader under the desk with repeater PCB on top solves this. I’ll make a little video showing all the ways it can be used.

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Yeah I am crazy proud of the read range of the large style v2 repeaters.

Once I get the smaller flex design completed I’m going to move on to having the larger design in flex too because I see the feedback for it.

The flex stickers you are coming out with are going to be really well tuned so you may get similar results with a smaller form factor.

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It definitely depends on the situation. This same exact PCB repeater doesn’t do anything on my nothing phone 2, only the smaller size works magic. It’ll be nice to have two types for different scenarios.

Yeah that is the plan. I just ordered my 2nd set of prototypes for flex. Im zeroing in my freqency for the flex. I have some great math equations now (in my own readable format) since i was able to get some great readings from my previous design and see where i messed up.

The biggest win was i figured out how to duplicate designs in Kicad on a separate layer. which was really messing up my first batch of designs.

Regardless i have it narrowed down pretty substantially. Ordered the new prototype, and i put an order in for more of the V2.1 small repeaters. Those seem to be really liked.

Weird though because Iceman said he got decreased performance from his flipper with it.

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Well it is totally possible to decrease the performance if you position it in the wrong place or the size ratio with the primary antenna coil is not conducive and in fact somewhat interferes.

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By the beard of Zeus! It actually works! :astonished:

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