Turning an Old Phone’s Motherboard into an RC Plane Controller

Upcycling smartphones makes a lot of sense, especially since they contain so many components that remain useful long after their desirability as a smartphone has faded. Turning an Old Phone’s Motherboard into an RC Plane Controller. In the case of [Mountain DS Lab], they opted to use an 8-year old Xiaomi Mi 8 phone to add long-range FPV video link and remote control functionality to an RC plane, using the phone’s LTE cellular connectivity.

The smartphone was bought used for $23, with the default Xiaomi ROM overwritten by LineageOS to get a more lightweight and up to date Android installation on it. From the video it’s clear that this phone has seen better days, with the glass back cracked and a few ugly lines running across the display. Fortunately all that is needed is the motherboard itself.

One gotcha here is that the OS checks for the display on boot and will time-out if it’s not present, potentially halting the process entirely. The workaround requires disabling the display in the device tree, which is done by modifying the boot.img file as explained in the video. Next a custom bracket for the motherboard was printed so that it could be fitted inside the target airplane.