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#638 – Building AR Headsets with Aedan Cullen
Welcome, Aedan Cullen!
- Chris first learned of Aedan from his 2022 Hackaday talk about building an AR system
- AR is “Augmented Reality”, but that term is different depending on the company / headset (think “magic leap” vs “google glass”)
- Got into AR because of robotics, he had be doing software around SLAM and CV
- Interacting with objects in 3D space
- The first board he was working with was the Jetson TK1
- Magic Leap’s “Lightpack” had a Tegra in it
- Apple’s new Vision Pro is more like VR with passthrough (and creepy eyes!)
- Being able to wear an AR unit all day
- Resolution matters
- What is it worth spending power on in a headset?
- The previous rev used the AllWinner D1 RISCV and can support one camera
- Which way should you point a camera on a pair of glasses?
- MIPI DSI outputs and DSP processing
- Lots of SIPs available for high density designs
- Octavo makes SIPs out of other companies’ silicon.
- Jason and Robert from BeagleBoard talked about Octavo when they were on the show
- ECX337 from Sony needs 10V
- Torex power modules helped save space too by being stacked on top of the inductor
- Sony uses LVDS (FPDlink) and not MIPI
- Offloaded processing to a phone or computer
- Power
- Wi-Fi vs bluetooth
- New goal is to minimize power during processing, now it’ll be efficiency around WiFi and Display
- With OLEDs you can selectively turn on pixels
- Goal for the battery is 8 hours for “all day”
- What is Aedan’s “requirements space” and what’s driving it?
- Cost has become a concern for new boards
- Using an assembly house to have one known-good assembly board
- What’s on the new board?
- The new display has MIPI DSI
- The display doesn’t support 2 lane DSI out of the box
- Displays are sometimes configurable in terms of how many lanes with registers
- What do the lanes refer to? Each pair (“Data lane”) is a differential pair
- Most displays will do 4 lanes (8 conductors) at 1Gbps
- “Giganibbles per second”
- Silicon backplane with OLED on top
- ViewTrix
- The processor is the NXP iMX RT500
- “This is design is made for Garmin”
- Aedan is coding it in Zephyr
- Drivers are in MCUexpresso
- DCnano display driver in Zephyr
- no GPU driver in Zephyr
- 2D GPU in the chip
- WiFi module is the same as the past rev, the Si Labs WFM200S
- Sending compressed data over the WiFi link
- Mechanical
- Tweaking displays and 3D printed mounts
- Prism
- Flex cables
- XReal / NReal
- Using your brain as the combiner
- The new display has MIPI DSI
- Zach from Voidstar
- Aedan just went to the Augmented World Expo in May. “No one was wearing an AR display around the conference”
- Vision for the future
- Follow Aedan online
- GitHub