Assembly · soldering · first flight
Build guide v3.
Step-by-step assembly for the DIY 5-inch practice rig. Revised for 2026 parts list (Jetson Orin Nano 8GB, RPi Camera 3 Wide). Budget: ~6 hours first build, ~3 hours with experience. See DIY build for BOM.
Time
~6 hr first build
~3 hr experienced
Tools
TS100 · 2.0mm / 2.5mm hex · hot glue
plus pliers, flush cut
Solder
63/37 · 0.8 mm · Kester flux
no lead-free for FPV
Prereq
DIY BOM in hand · printed brackets
see 3D parts
§ 01Stage 1 · Frame + motors
- Unpack frame. Separate: bottom plate, top plate, 4× arms, 4× M3×16 standoffs, hardware.
- Attach arms to bottom plate with M3×8 hex. Torque to snug + ⅛ turn.
- Drop in 4× motor-wire grommets (frame arm openings).
- Mount motors (M3×8 from bottom). Orient bell so CW/CCW matches layout.
- Route motor wires inward toward center. Leave ~2cm slack.
§ 02Stage 2 · ESC + PDB
- Place ESC on bottom plate via anti-vibration O-rings.
- Solder 12-gauge XT60 leads + capacitor (35V 470µF) to battery pads.
- Tin motor pads. Solder motor leads — flush, no bridges.
- Continuity test: each motor phase to battery + / − should not short.
- Confirm 5V + 9V BEC outputs with a multimeter before connecting FC.
Before first power-up: visually inspect every solder joint. A cold joint or flux bridge can fry an ESC faster than you can blink. If in doubt, reflow.
§ 03Stage 3 · Flight controller
- Stack Kakute H7 V2 on ESC via included isolators.
- Connect ESC signal ribbon to FC motor outputs (S1–S4, GND).
- Wire RX: ELRS TX → FC UART6 RX; ELRS RX → FC UART6 TX; plus 5V + GND.
- Wire MAVLink bridge: FC UART2 → Orin UART (115 200 baud).
- Power on bench (no props!). Confirm Betaflight / PX4 sees FC over USB.
§ 04Stage 4 · Compute + camera
- Mount 3D-printed Jetson Orin bracket on top plate (M2.5×6).
- Seat Orin Nano Dev Kit. Secure with M2.5 through carrier board holes.
- Wire 5V buck from ESC to Orin barrel jack (5V 3A minimum).
- Route RPi Cam 3 CSI ribbon to Orin's CSI-1. Add strain-relief clip.
- Mount camera with printed ~30° downtilt bracket (sim's camera angle).
- Cable-tie all wires away from props + motors. Heat shrink strain points.
§ 05Stage 5 · Firmware + configuration
# Flash Orin Nano Super SD image
# Boot, set up Wi-Fi, ssh keys
sudo apt install mavlink-router
# /etc/mavlink-router/main.conf — UART 115200, UDP 14550 out
# On Orin, clone our stack
git clone https://github.com/blakefarabi/grandprix.git
cd grandprix
bash diy_rig_setup.sh # installs python deps, downloads weights
On the FC (Betaflight or PX4), set:
- MAVLink telemetry output on UART2 @ 115 200
- Failsafe: disarm on RC loss within 1 s
- Angle mode disabled (acro only) — we want raw rate control
- Blackbox logging to SD · for post-flight debrief
§ 06Stage 6 · First flight checklist
Follow the 10-point checklist in DIY build §04. Props on only after steps 1–6 pass.
Budget: first flight ≈ 20 min hover in a netted indoor area. Don't chase speed on day one. The goal is clean telemetry for the sim-to-real residual model, not a fast lap.