1Finding and modifying a suitable phone
Required is a phone with a long flex cable leading to one of the cameras. In my research Chinese MIX smartphones are most suited. These have flex cables of ~10cm to the front camera (which is located at the bottom of the phone, instead of the top). You might have to look if spare camera parts are available, as it may be easier to buy a $10 spare camera than to disassemble the phone (more than necessary) and risk damaging it.
My first successful test has been done with the VKWorld S8. This phone has a rather large battery and places a significant weight on your head, but does provide for a long battery lifetime. I have ordered a spare front camera so I didn't need to unearth the original front camera from below the battery pack, saving some hassle.
My second test will be with the Leagoo KICAA MIX. This phone has the front camera flex cable running over the top of the battery, making it easy to detach the front camera without taking the battery out.
Lastly the postional tracker I have developed uses the camera flash to detect reflective markers. Thus the camera flash LED needs to be ran outside the phone to be positioned next to the external camera. Some soldering is required. The original SMD LED needs to be desoldered and two long wires need to be attached to the points. A 1 or 3 watt wide angle LED is used and attached to the wires. I have placed a 300ohm resistor in series to dim the light as to be not too bright.
- Chinese AR glasses Link
- A 1 or 3 watt LED (note a colored LED works well with clear reflective markers, otherwise a white LED with colored markers works also)
- A MIX phone with long flex cable to the front camera For example this one
- Reflective markers Such as these to test with
- In the future custom reflective QR markers will be used
Software and hardware needs to be calibrated:
- The correct camera resolution needs to be specified
- The correct camera angle in relation to the display needs to be specified
- The phone angle in relation to the eyes needs to be specified
- The display angle needs to be specified
Once thats done (or done for you), a short calibration step needs to be done in order to put the camera into low-exposure mode. This needs to be done at least once every phone-reset. Currently the tracker service auto calibrates to the marker/LED color and light levels. It also times the intervals of the flash LED toggling - as this is not immediate and can vary per phone.