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Prototype readable

A project log for No battery NFC air pressure sensor

Measure tire or ball pressure with your smartphone

captmcallisterCaptMcAllister 10/12/2015 at 03:210 Comments

October 11, 2015: I made a bit of a breakthrough today. I finally populated a couple of my boards and put antennas on them, and I am able to read them with my cell phone. There's a picture of the prototype in the pictures section. I am not yet reading pressure, as I didn't put the pressure sensor on yet. I wanted to test the function and tuning of the antenna first. I put a 3.3 uH inductor in parallel with the antenna, but that isn't small enough. I also have 820 nH, but that's too small. I need to get 0402 inductors around 2.6 uH, and then it will be easy to tune. However, right now I can read it about 1 cm away. I'm hoping to hit more like 4 cm, and even then, I'm not sure how well it will do through a typical bike tire. You can get readers with higher power, but that defeats the purpose of the project, which is to read your tire pressure with the cell phone you already have in your pocket.

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