NRO4 - 3d Printed Nano Rocket FPV Drone With DJI O4

Nano Rocket O4 is a fully 3d printed FPV drone for 2" props powered by a single cell lipo. The goal is to reach +100km/h with this small and low volt setup. You can use tinywhoop parts. However 1002/1003 motors are strongly recommended. Basic knowledge on 3d printing and FPV drones is strongly advised for this build.

BOM

Betafpv Matrix

DJI O4

1002 motors

GPS

Props

Antenna

M1.4x5

1. download the .stl files for free at Thingiverse or Printables
2. print the files (caps 4x). I used 20% infill, support on buildplate only and PETG
3. remove support on top and bottom (head and cone .stl)

Base

1. Solder the GPS to UART 2 of the Matrix AIO flight controller. GPS RX goes to TX2 and GPS TX to RX2. Power with the 5v (+) and Gnd (-) pads on the board.
2. Put the Matrix AIO into the 3d printed base. ELRS antenna and USB port face downwards.
3. Mount the motors to the arms, use M1.4x5. Motor wires go under the arms of the base into the hole and then to the ESC pads of the Matrix AIO. Glue the 3d printed caps on top of the motor mounts.
4. Solder motor wires to the Matrix AIO
5. Put the DJI O4 air unit on top of the Matrix AIO. Connect both with the included wire harness. Use grommets in both boards and mount with M2 screws into the base.

Top ("Head")

1. First put the DJI O4 camera into the hole. You can't rotate the picture, so insert camera with Mipi-cable on top.
2. Then insert GPS (press fit for 12mm ceramic antennas)
3. Finally put Head on base. ensure that camera faces in flight direction (there is an arrow indicator on the Matrix AIO, you can adjust afterwards in Betaflight too).

Bottom ("cone")

1. Insert the cone into the base. Take care of the cut outs. There are 4 cut outs for the motor wires and 1 for the Matrix AIO USB port.

Basic Betaflight knowledge is a prerequisite. You can acquire it with youtube tutorials (eg search for Bardwell Betaflight)

1. You need to update Matrix AIO firmware and include the GPS option. Disconnect GPS and O4 for the update to work
2. Enable GPS on UART2, and digital OSD over MSP on UART4
3. Enable GPS in Config (UBLOX protocol)
4. Adapt the OSD. I recommend placing the speedometer in the center.
5. Set up RC link
6. Ensure correct motor position and direction

The following steps are necessary to fly:

1. Turn on DJI goggles and RC transmitter
2. Insert the 1s battery into the cone. Plug battery into the Matrix AIO. Place drone on a surface to ensure correct calibration. After the beep you can move the drone again.
3. Fit the cone on the base. Ensure that all cut outs fit right on the arms / USB port and that the ELRS antenna fits into the cone.
4. Carefully start the drone by hand.

Have fun!