Showing posts from January, 2015

Wiring little wires to stuff or “How did I get fingerprint scanner”

So I had/have a semi-old dead laptop. The motherboard is dead, everything else works. It’s a Dell XPS M1330. It has a fingerprint scanner that made my curious. How does it work? How is it connected and can I use it?
I ripped the laptop open and extracted all kinds of fun stuff including the fingerprint sensor.
It has a little chip with a writing  / / TCD42A1DN0 / /
So I started investigating.
First thing that threw me off was the 6 pin ribbon cable (USB typically uses 4).

Finding ground pin is the easiest – Found that.
Found the power pin- It was a line that had a capacitor connected with the ground. So I assumed this was the power pin.
Two pins are unpopulated.
Two pins are connected to resistors – starts to seem like USB data lines~.


Interfacing it.

Typically all internal laptop stuff uses 3.3V. So that seemed a safe way to go. I need to use a voltage converter to step down from 5V.

It has a ribbon cable, so that’s a no go. Removed that and the plug and decided to connect wires direc…