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It's time for another rousing round of "Name That Component"!

Black square on flat flex

Today's participant hails from a Bluetooth combo keyboard/mouse, where it detects finger motion across it which the Bluetooth chip translates into relative motion HID messages. It (supposedly) uses an imager of some sort to detect motion of an object that contacts the surface. Does this little beast have a proper name?

(The other side only has a metal key dome under a white sticker which when depressed the Bluetooth chip converts to a middle-click HID message.)

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Interesting component, I am waiting for an answer, I wondered if it is an IR transceiver, but there sure are alot of traces for such a simple device. Even if it were x and y, that is still a lot of traces. Even if it were a form of capacitive sensor, that is still a bunch of traces. Even if it used capacitive or resistive sensing for the "touch detection" and reflective optical sensors for the movement..it still has a lot of traces. Very interesting! My interest has been piqued! – Enemy Of the State Machine Aug 2 '14 at 6:10
up vote 6 down vote accepted

That, my friend, is an Optical Finger Navigation Sensor. Specifically, it looks like something out of the Avago portfolio that's been sold off to Pixart Imaging; they currently sell the ADBM-A350 (Datasheet) that I would look at for more information. This also comes in a sensor-only package, the ADBS-A350, that you could use if you wanted to do your own optical design. Essentially, it works the same way an optical mouse sensor works -- a low-resolution image sensor tracks pixel intensities to determine displacement.

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