RFID Power Delivery Wearable

Thread Starter

leumas95

Joined May 20, 2016
2
So I have a project I'm working on a project to light these "NFC fingernail lights":

s-l400-4.jpg
They light up when in the presence of a 13.56MHz RFID field. The issue is other than my phone, I have no way to light them day to day.

I would like to develop a device I can hold, like fist semi closed and it would light up the fingernails.

I have had some success with a Pierce Occiliator, infact it 100% works. The issue is to get a brightness I am happy with I need to provide ~30v from my variable power supply. For reference here is the schematic of the circuit that worked for me:
51f3ce0ccab99dfc5b8a27d517ef23f375393272_2_586x750.jpeg

Unfortunately given I want this to be compact I don't think this circuit will work for me, or at least I don't know how to tweak it to work better for my usecases.

I haven't had much luck finding anything helpful in the internet. Everything relating to RFID focuses on reading and writing.

Also a stretch goals for me would be to instead have a bracelet that if I curled my fingers towards the wrist it would still be able to power it but I'm not sure how realistic that is.

Any guidance would be much appreciated. I am fairly competent at wiring things up, making my own antennas and that sort of thing but the RF stuff kinda goes over my head.
 

Delta prime

Joined Nov 15, 2019
329
Your schemo is not a Pierce oscillator because there is no feedback. A typical scheme, where R1 is feedback.1589064224755.jpg
You have not s satisfied the BarkHausen criteria.:( I could light up a dark room with those fingernails.You got nice idea! Thanks.
I just stold somebody's project nobody will ever know.:p
 

Thread Starter

leumas95

Joined May 20, 2016
2
Your schemo is not a Pierce oscillator because there is no feedback. A typical scheme, where R1 is feedback.View attachment 206751
You have not s satisfied the BarkHausen criteria.:( I could light up a dark room with those fingernails.You got nice idea! Thanks.
I just stold somebody's project nobody will ever know.:p
Are the 33k and 22k resistors in series not providing feedback?
Regardless of the name of the circuit using (I just used the label given to that schematic)
Do you think I would have better luck with the one you provided? If so how would I go about selecting values for each of the components for my usecases?

Feel free to "steals" the project lol, if you have any luck I'd obviously be great full for an update given I'm well out of my depth here.
 
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