Drone remote controller

Projects

A radio controller for the quadcopter, designed and 3D printed from scratch, that shows live telemetry from the aircraft on its own screen.

Personal projectIndustrial design3D printingEmbedded systems

LCD: what the aircraft sends backSticks: read and sent 50 times a second, moving or notStick positions leave on the nRF24L01 at a fixed 50 Hz, so the count keeps rising while the sticks are still: a dropped packet is one missed update, and silence means the link is gone. The aircraft answers on the same radio with its arming state, flight mode, battery and attitude, shown on the 20×4 LCD. The left buttons arm it, the right ones switch modes.

RoleSole designer and engineer

StackC++ · CAD · FDM 3D printing · nRF24L01 · LCD telemetry

The problem

The quadcopter needed a way to be flown. A controller stays in your hands for the whole flight, so the hard part is not the radio link. It is that the shape, the stick feel and the layout decide whether the aircraft is actually controllable.

Constraints

Enclosure modelled in CAD and printed on an FDM printer
Print volume and layer adhesion set the maximum part size and where seams could fall
Must run on battery for a full flying session
nRF24L01 radio: short range, shared by commands going out and telemetry coming back
Stick input has to reach the aircraft with latency low enough not to be felt

Decisions

Design around the hands first, then fit the electronics

The grip angle and stick spacing were modelled and printed before the board layout was fixed, so the internals had to fit the shape rather than the shape growing around a PCB. Holding a printed shell is the only way to find out that it is wrong.

Print in parts with captive fasteners

A single-piece shell would have needed supports across the grip and left a poor surface exactly where it is held. Splitting the enclosure put the seams where the hands are not, and made every internal part serviceable without cutting anything.

Send stick positions at a fixed rate, not on change

A steady stream of small packets makes a dropped one a single missed update rather than a lost command, and it gives the aircraft a clear signal to detect when the link is gone.

Bring telemetry back to the pilot's hands

The link runs both ways: the aircraft answers with battery voltage, attitude, flight mode, armed state and link quality, shown live on an LCD on the controller. With a short-range radio, seeing the signal degrade before it drops is what lets the pilot turn back in time.

What I'd change

I iterated the enclosure far more times than the electronics, and each iteration cost hours of print time. Printing just the grip section as a test part first would have got me to the right shape for a fraction of the filament.