Low Profile Light and More Functional NFC LED implants

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Back in the day, Grindhouse Wetware had a project called “Low Profile Light” that was intended as a successor project to the Northstar v1 (the implant that was able to light up if you put a magnet next to it).

The project was essentially a small (~1 square cm) NFC-powered LED implant - not too unlike the xLED but with a couple of twists. The LED was controlled by an attiny microcontroller, and the hardware was capable of receiving power, communication, and even code flashing over NFC (so you could program it with PWM, or funky blink patterns, or to react to data from your phone while coupled). It also had a power source in the form of tiny supercaps that could store enough energy to light the LED for one minute (or you could PWM it to extend it).

Anyway, GHWW abandoned this project to focus on Northstar v2, so we ended up releasing the Low Profile Light schematics into the public domain in the hope that someone else would be able to make use of it. But it shouldn’t be terribly hard to prove out this design and turn it into a functional implant, so I’ve been thinking about working on it again.

Here are the schematics if anyone else is also interested in playing around with the design: https://drive.google.com/drive/folders/0B3p99D0AGrsEYlZ1Z09JN0tQYkk

EDIT: Or I just uploaded them here.

Low Profile Light - Release-20260122T041134Z-3-001.zip (206.6 KB)

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Requested access

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Me also.

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@Hamspiced @tac0s I just attached the files to the OP so you can also grab them from there directly.

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Some ideas I saw on the biohack.me forum to improve the design that I’m recording here:

  • Replace the attiny13 with an attiny841. It’s the same size and only consumes 5% more power (25% in low power mode), but it can still be programmed over SPI, has more memory, and has a second SPI bus which provides more flexibility for future expansion.

  • Replace the supercaps with a V18HRT rechargeable NiMH coin cell from Varta, which might handle the current better.

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It looks like they no longer make the AS3955 (the SPI NFC chip) so I need to look for a suitable replacement.

Also worth noting that there are enough spare GPIO pins for a three-color LED (especially if we use the attiny841), which could enable more interesting programs without sacrificing too much area.