Introduction

Context: Varifocal

We need to make a board to deliver power to all of the various breakout boards, as well as the voice coil motors.

As a bonus, this board could have the MCU/IMU for tracking integrated, as well as the PWM output for the voice coils. This would make it essentially the motherboard of the varifocal headset.

System Diagram (drawn)

Click in to view full-size image.

Click in to view full-size image.

The headset should be as standalone as possible. Current plans are all electronics are powered from within the headset. Only cable to the computer should be the display cable.

We are currently using the Northstar displays, display driver board, and SLAM functionality, which serves as it’s own separate system. It receives power from the same USB-C cable it receives data. This is currently completely separate from the Motherboard.

Minimum Feature Set

Data:

No plans currently. May change in the future.

Components

Voice Coil Motor Selection

We reached out to GEEPLUS for their offerings.

image.png

We chose both the 180 and 112 models to prototype with.

Motor Driver

https://www.digikey.ca/en/products/detail/texas-instruments/TAS5421QPWPRQ1/4935045

https://www.digikey.ca/en/products/detail/texas-instruments/TPA3112D1PWPR/2170376