I’ve had this idea in the back of my head for quite a while now, a small clock, placed under the skin and shows the time by shining light through it. To avoid draining the battery and causing excess heat the time should only be displayed when you tell it to.

I decided to approach the trans-dermal input with a very simple but functional idea, magnetic activation using a reed relay…….Anyone willing to put a clock inside their body, has probably already inserted a magnet into a finger

My original idea was very simple, take an Arduino Nano, Neopixel ring, QI receiver and a Li-Po, arrange it nicely and bioproof* it.

But the more I thought about it, it started sounding worse and worse, having a huge development board that is barely used, a large PCB with nothing but LED’s, a separate QI receiver and so on.

*(That I do not know how to do, something I have to educate myself on if I wish to create this device)

(Most ideas begin with crude whiteboard drawings)

I did however thing the basic electronics behind it was logical, so I spent some time deconstructing every single piece of it and start designing it as a single PCB

(Block image of the design)

After having the basic concept down, I went and read up on the necessary IC’s to make this both function.

This design uses the

LM7805 for power regulation (WIP component, it’s too big for real usage)

MCP73831 for charging the Li-Po

bq51013B as a QI receiver

ATmega328P as micro-controller

WS2812 for the leds

RTC module has not been picked



(the basic circuit design)

How it would look

In conclusion, I think this is an interesting concept to play with, far far away from being a realistic idea today but, we could make this a reality within a few years