# DIY 5-inch Racer Build · Archer-class clone

**Doc version:** 4.0 (Orin NX 16GB migration)  
**Date:** 2026-05-27  
**Source:** https://aigp-dashboard.pages.dev/documents/diy-5inch-racer-build  
**Purpose:** Reproducible 5-inch FPV quadrotor cloning the airframe envelope of
the Neros Archer, kitted out with a **Jetson Orin NX 16GB** for onboard autonomy
and AIGP sim-to-real data capture. Previous v3.0 of this doc used the Orin Nano
Super 8GB; v4.0 upgrades to the NX to give the AIGP perception → planner →
controller stack headroom at the 25 m/s ATTACK profile.

---

## At a glance

| Spec | Value | Notes |
|---|---|---|
| Form | 5″ TrueX · 6S | commodity supply chain |
| Dry weight | ~270 g | no battery, with NX module + DAMIAO carrier (36 g) |
| Target TWR | 5–6× | race class |
| Top speed | ~150 km/h | limited by motor KV at 6S |
| Compute | **Jetson Orin NX 16GB** | 100 TOPS · 25 W MAXN · SO-DIMM 260-pin |
| Vision | RPi Camera Module 3 Wide (IMX708) · 120° FOV | matches Archer-class autonomy cam |
| Drone-only cost | ~$1,650 | excludes shared gear · DAMIAO carrier saves ~$100 vs J401+BEC |
| First drone fully kitted | ~$2,988 | includes radio + goggles + charger + tools + printer |

---

## §01 What we're cloning

The [Neros Archer](https://www.neros.tech/) is a US-built 5-inch FPV designed
for ISR + tactical payload work — small, fast, hard to source overseas. We
can't and don't need to clone the mission systems. What we DO clone is the
airframe envelope and propulsion class, swap in a **Jetson Orin NX 16GB** for
autonomy, and bias the build for data-capture reliability over kinetic
mission specs. (v3.0 used an Orin Nano Super 8GB — we moved to the NX once
the AIGP pipeline's YOLO11n-pose + EKF + planner stack outgrew the Nano's
67-TOPS budget on the 25 m/s ATTACK profile.)

| | Archer (public) | Our clone |
|---|---|---|
| Class | 5″ FPV · ISR/strike | 5″ FPV · same envelope |
| Frame | carbon TrueX, custom | iFlight Nazgul5 V3 TrueX |
| Propulsion | ~2207 brushless · 6S | XING2 2207 2750 KV · 6S |
| Range | multi-km, encrypted | ELRS 2.4GHz · kill-switch only |
| Vision | HD digital, onboard processing | RPi Cam 3 Wide → Jetson Orin NX 16GB |
| Supply | US-domestic, restricted | commodity, off-the-shelf |
| Mission | ISR · payload delivery | sim-to-real telemetry · gate flight |

This is a **data-capture rig**, not a race drone. Optimize for reliability
and predictable dynamics so the residual-dynamics model sees clean data.

---

## §02 Bill of materials · full

Prices are 2026 USD street estimates. Always check current pricing.
"alt" rows are tested-good substitutes if the primary is out of stock.

### §02.1 Airframe + hardware

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| iFlight Nazgul5 V3 · TrueX 5″ frame | 1 | $80 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=iFlight+Nazgul5+V3) · [iFlight direct](https://shop.iflight.com/search?type=product&q=Nazgul5+V3) |
| alt: Apex 5″ HD | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Apex+5+HD+frame) |
| alt: GepRC Mark5 HD | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=GepRC+Mark5+HD) |
| M3 hardware kit (M3×6/8/12, nylocks) | 1 | $8 | [Amazon](https://www.amazon.com/s?k=M3+screw+kit+M3x6+M3x8+M3x12+nylock) |
| Soft-mount grommets · M3 silicone | 8 | $4 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=M3+silicone+grommet+soft+mount) |
| Battery strap · Kevlar 200 mm | 2 | $6 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=battery+strap+kevlar+200) |
| **Airframe subtotal** | | **$98** | |

### §02.2 Propulsion

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| iFlight XING2 2207 · 2750 KV · 6S | 4 | $100 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=iFlight+XING2+2207+2750KV) · [iFlight](https://shop.iflight.com/search?type=product&q=XING2+2207+2750) |
| alt: T-Motor Velox V2 2207 2750 KV | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=T-Motor+Velox+V2+2207+2750) |
| alt: Brother Hobby Avenger 2207 | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Brother+Hobby+Avenger+2207) |
| HQProp 5×4.3×3 V1S triblade | 8 | $24 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=HQProp+5x4.3x3+V1S) |
| alt: Gemfan 5152S v2 (wind) | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Gemfan+5152S+v2) |
| alt: Azure 5147 (race) | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Azure+5147) |
| **Propulsion subtotal** | | **$124** | |

See §05 propeller guide for full picks by use case.

### §02.3 Flight electronics

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| Holybro Kakute H7 V2 FC | 1 | $85 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Holybro+Kakute+H7+V2) · [Holybro](https://holybro.com/search?q=Kakute+H7+V2) |
| alt: SpeedyBee F405 V4 (F4 only, cheaper) | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=SpeedyBee+F405+V4) |
| alt: Mateksys H743-Slim | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Mateksys+H743-Slim) |
| Holybro Tekko32 F4 4-in-1 · 50A 6S ESC | 1 | $110 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Holybro+Tekko32+F4+50A) |
| alt: T-Motor F55A Pro II | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=T-Motor+F55A+Pro+II) |
| Cap 35V 1000µF Panasonic FR/FM | 1 | $4 | [Digi-Key](https://www.digikey.com/en/products/result?keywords=panasonic+35V+1000uF+FR) |
| XT60 pigtail · 14 AWG · 100 mm | 2 | $8 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=XT60+pigtail+14AWG+silicone) |
| **Flight electronics subtotal** | | **$207** | |

### §02.4 Radio link (safety pilot only)

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| ExpressLRS 2.4 GHz EP2 RX | 1 | $22 | [BetaFPV](https://betafpv.com/search?q=ELRS+EP2) · [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=ExpressLRS+EP2) |
| alt: RadioMaster RP3 | – | – | [RadioMaster](https://www.radiomasterrc.com/search?q=RP3) |
| alt: BetaFPV ELRS Nano | – | – | [BetaFPV](https://betafpv.com/search?q=ELRS+Nano+receiver) |
| RadioMaster Boxer ELRS TX **(shared, 1 per team)** | 1 | $260 | [RadioMaster](https://www.radiomasterrc.com/search?q=Boxer+ELRS) · [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=RadioMaster+Boxer+ELRS) |
| **Radio subtotal (incl. shared)** | | **$282** | |

### §02.5 Video link · human spotter

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| Walksnail Avatar HD Mini VTX V2 | 1 | $90 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Walksnail+Avatar+HD+Mini+VTX+V2) |
| alt: DJI O3 Air Unit | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=DJI+O3+Air+Unit) |
| alt: HDZero Race V3 | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=HDZero+Race+V3) |
| Walksnail Nano camera | 1 | $32 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Walksnail+Nano+camera) |
| TrueRC X-Air 5.8 GHz MMCX antenna | 1 | $22 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=TrueRC+X-Air+5.8+MMCX) |
| Walksnail Avatar HD Goggles **(shared, 1 per team)** | 1 | $430 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Walksnail+Avatar+HD+Goggles) |
| **Video subtotal (incl. shared)** | | **$574** | |

### §02.6 Autonomy stack

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| **NVIDIA Jetson Orin NX 16GB module** | 1 | $699 | [Arrow](https://www.arrow.com/en/products/search?q=Jetson+Orin+NX+16GB) · [Mouser](https://www.mouser.com/c/?q=Jetson+Orin+NX+16GB) · [Silicon Highway](https://www.silicon-highway.com/products/nvidia-jetson-orin-nx-16gb) |
| alt: Orin NX 8GB module ($599, same compute, half RAM) | – | – | [Arrow](https://www.arrow.com/en/products/search?q=Jetson+Orin+NX+8GB) |
| alt: Orin Nano Super 8GB Devkit (cheaper but we outgrew it) | – | – | [NVIDIA](https://www.nvidia.com/en-us/autonomous-machines/embedded-systems/jetson-orin/nano-super-developer-kit/) |
| **DAMIAO Orin NX RC/Drone Carrier V1.1** *(87 × 50 mm · 36 g · XT30 input · JST-GH MAVLink · drone-native)* | 1 | $50 | [eBay](https://www.ebay.com/sch/i.html?_nkw=DAMIAO+ORIN+NX+Carrier+Board+V1.1) · [HamGeek full kit](https://www.hgeek.com/products/hamgeek-damiao-orin-nx-carrier-board-drone-development-accessory-v1-1-suitable-for-nvidia-jetson-orin-nx-1) · [Thanksbuyer](https://www.thanksbuyer.com/products/damiao-orin-nx-carrier-board-drone-development-accessory-v1-1-suitable-for-nvidia-jetson-orin-nx) |
| alt: Seeed reComputer J401 (desktop ports, 60 g · if DAMIAO out of stock) | – | – | [Seeed](https://www.seeedstudio.com/reComputer-J401-Carrier-Board-for-Jetson-Orin-NX-Nano-p-5636.html) |
| alt: Forecr DSBOARD-NX-LT (drone-tailored 87×55) | – | – | [Forecr](https://forecr.io/products/dsboard-nx-lt) |
| alt: ARK Jetson PAB (ArduPilot-native, $300+) | – | – | [ARK Electronics](https://arkelectron.com/product/ark-jetson-pab-carrier/) |
| NVMe SSD 256GB M.2 2280 | 1 | $32 | [Amazon](https://www.amazon.com/s?k=Samsung+980+256GB+NVMe+M.2+2280) |
| RPi Camera Module 3 Wide (IMX708) | 1 | $35 | [Adafruit](https://www.adafruit.com/product/5657) · [RPi direct](https://www.raspberrypi.com/products/camera-module-3/) |
| alt: Arducam IMX477 12MP wide | – | – | [Arducam](https://www.arducam.com/?s=IMX477+12MP+wide) |
| CSI-2 ribbon 22→15-pin adapter · 200 mm | 1 | $15 | [Arducam](https://www.arducam.com/?s=22+pin+to+15+pin+CSI+adapter) |
| XT30 male-to-female pigtail · 150 mm · ESC PDB → DAMIAO XT30 input | 1 | $3 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=XT30+pigtail) |
| External BEC 5V/6A *(optional — only if you fall back to J401)* | 0–1 | $0 | [Matek 5V/12V 6A](https://www.getfpv.com/catalogsearch/result/?q=Matek+BEC+5V+12V+6A) · [Pololu D36V28F5](https://www.pololu.com/product/3791) |
| 40 mm 5V cooling fan + heatsink *(required for NX)* | 1 | $8 | [Amazon](https://www.amazon.com/s?k=40mm+5V+brushless+fan+jetson+heatsink) |
| 3D-printed NX carrier mount (PETG) | 1 | $2 | in-house |
| 3D-printed RPi Cam +20° tilt mount (PETG) | 1 | $1 | in-house |
| **Autonomy stack subtotal** | | **$842** | |

### §02.7 Power

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| Tattu R-Line 1300mAh 6S 120C battery | 3 | $120 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=Tattu+R-Line+1300mAh+6S+120C) |
| alt: CNHL Black Series 6S 1300 120C | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=CNHL+Black+Series+1300+6S+120C) |
| alt: GNB 6S 1300 120C | – | – | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=GNB+1300+6S+120C) |
| ToolkitRC M7 100W charger **(shared)** | 1 | $80 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=ToolkitRC+M7) · [ToolkitRC](https://www.toolkitrc.com/M7) |
| Mean Well 24V/4A bench PSU **(shared)** | 1 | $40 | [Amazon](https://www.amazon.com/s?k=Mean+Well+24V+4A+power+supply+LRS-100-24) |
| LiPo safe bag · 30 cm | 2 | $14 | [Amazon](https://www.amazon.com/s?k=LiPo+safe+bag+30cm) |
| **Power subtotal (incl. shared)** | | **$254** | |

### §02.8 Safety + misc

| Part | Qty | USD | Buy |
|---|---:|---:|---|
| 5″ prop guards (printed PETG) | 4 | $4 | in-house |
| 5V piezo buzzer | 1 | $3 | [GetFPV](https://www.getfpv.com/catalogsearch/result/?q=5V+piezo+buzzer+FC) |
| USB-C cable 1 m (data) | 1 | $6 | [Amazon](https://www.amazon.com/s?k=USB-C+data+cable+1m+5A) |
| Cable ties 100 mm UV-stable | 1 pack | $3 | [Amazon](https://www.amazon.com/s?k=cable+ties+100mm+UV+resistant) |
| **Safety + misc subtotal** | | **$16** | |

---

## §03 Tools & consumables (all shared, buy once)

| Tool | USD | Buy |
|---|---:|---|
| Pinecil V2 soldering iron | $45 | [Amazon](https://www.amazon.com/s?k=Pinecil+V2+soldering+iron) |
| Kester 63/37 solder 0.5 mm | $25 | [Amazon](https://www.amazon.com/s?k=Kester+63%2F37+solder+0.5mm) |
| MG Chemicals 8341 flux pen | $10 | [Amazon](https://www.amazon.com/s?k=MG+Chemicals+8341+flux+pen) |
| Helping hands + magnifier | $30 | [Amazon](https://www.amazon.com/s?k=helping+hands+soldering+magnifier+LED) |
| Hex driver set M2/M2.5/M3 (Wera/Wiha) | $35 | [Amazon](https://www.amazon.com/s?k=Wera+hex+driver+set+M2+M2.5+M3) |
| Digital multimeter | $25 | [Amazon](https://www.amazon.com/s?k=digital+multimeter+continuity+diode) |
| Heat-shrink kit 2–12 mm | $8 | [Amazon](https://www.amazon.com/s?k=heat+shrink+tubing+kit+2mm+12mm) |
| Soft-jaw bench vise | $40 | [Amazon](https://www.amazon.com/s?k=soft+jaw+bench+vise+small) |
| 3D printer (Bambu A1 / Prusa Mini) | $300 | [Amazon](https://www.amazon.com/s?k=Bambu+Lab+A1+3D+printer) |
| Plasti-Dip black | $10 | [Amazon](https://www.amazon.com/s?k=Plasti+Dip+black) |
| **Tools subtotal** | **$528** | |

---

## §04 Cost summary

| Line | USD |
|---|---:|
| Drone-only · per unit (no shared gear) | **$1,650** |
| Shared (radio + goggles + charger + PSU) | $810 |
| Shared (tools + 3D printer) | $528 |
| **First drone, fully kitted-out** | **$2,988** |
| **Each additional drone** | **$1,650** |

Excludes spares (props consumed per-flight, motors per crash) and a
Jetson dev-host machine (any modern laptop). Budget +20% shipping/customs
if outside the US. The +$500 vs v3.0 is the NX module ($699 vs Nano dev kit
$250) + drone-native DAMIAO carrier ($50, replaces both J401 and external
BEC) + 40 mm cooling fan ($8) + XT30 pigtail ($3) — net delta ~+$490 on
the autonomy stack. (The DAMIAO route saves us ~$100 vs the original
J401 + Mateksys BEC plan from earlier this draft.)

---

## §05 Propeller guide

The single biggest tunable on a quad is the propeller. Diameter, pitch,
blade count, and material decide the entire personality of the build.
For this rig we prioritise PREDICTABLE dynamics for the sim-to-real
model, not raw top speed.

### Reading a label

`DD×P×B` = diameter × pitch × blade count. A `5×4.3×3` prop is 5″ across,
theoretically advances 4.3″ per rotation, has 3 blades.

| Pitch (5″) | Feel | Top speed | Hover throttle | Best for |
|---|---|---|---|---|
| 5×4.0 | smoothest, easiest | low | ~22% | indoor / beginner |
| **5×4.3** | **balanced, predictable** | **mid** | **~24%** | **AIGP data capture (this build)** |
| 5×4.5 | snappier | mid | ~25% | freestyle / general race |
| 5×5.0 | aggressive, sharp punch | high | ~28% | open-air race |
| 5×5.5 | edge of overheating motors | v.high | ~30% | experts only |

### Blade count

| Blades | Efficiency | Bite | Sound | Best for |
|---|---|---|---|---|
| 2 | highest, longest flights | lowest | quiet whoosh | long-range cruise |
| **3** | **balanced** | **good** | **standard FPV buzz** | **default for everything** |
| 5 | lowest, short flights | highest | aggressive growl | cinematic / stunt |

### Rotation pattern (props-out, BetaFlight default)

```
M4 (FL) CW  ╲   ╱ CCW M1 (FR)
              ╳
M3 (BL) CCW ╱   ╲ CW M2 (BR)
```

Pyramid mark on the prop hub points UP. Mismatched direction = motor
stalls + ESC overheats on takeoff.

### Recommended sets

| Prop | Use case | $/set |
|---|---|---:|
| **HQProp 5×4.3×3 V1S** (primary) | smoothest IMU read, ideal for data capture | $3 |
| HQProp 5×4.3×3 V2 | race-tuned re-spin, sharper response | $3 |
| Gemfan 5152S v2 | outdoor wind, more inertia | $3 |
| Ethix S5 (5×4×3) | indoor / hover trim work | $3 |
| Azure SFP 5147 | drop-in alt if HQ V1S sold out | $3 |
| HQProp 5×4×3 Light | soft-flex for prop-guard indoor | $3 |

### Stocking

- 1 set in service (4 props)
- 1 set spare ready at the field (4 props)
- 5–10 sets stocked for a 30-min training campaign per drone
- Replace any prop after chip / dent / audible vibe — pollutes IMU data
- One bad prop = replace all four (matched-set rule)

### Pre-flight prop check (30 seconds)

1. Flick each blade with fingernail — should ring clear, not buzz
2. Inspect both faces for cracks
3. Bench-run motors at 10% throttle with hand on the frame — any unexpected vibration = swap

---

## §06 Assembly order

1. **Frame prep.** Unbox, deburr arms with 1000-grit. Dry-fit all 8 frame screws.
2. **Mount motors.** Confirm CW/CCW pattern matches ESC firmware. Standard: M1=FR-CCW, M2=BR-CW, M3=BL-CCW, M4=FL-CW.
3. **Solder motor leads to ESC.** Pre-tin both. Multimeter-test for shorts pad-to-pad and pad-to-XT60.
4. **Mount ESC.** 4× M3×6 into bottom plate via silicone grommets.
5. **Solder XT60 + capacitor.** Cap across battery leads (negative stripe = GND). Heat-shrink the cap.
6. **Stack the FC.** 4× M3×22 standoffs from ESC. Drop Kakute on, FPV cam connector forward.
7. **Connect ESC ↔ FC.** 8-pin signal cable to FC ESC port. Don't reverse.
8. **Wire radio.** ELRS RX → FC UART6. Mount RX rear, antennas in a V.
9. **Wire VTX.** Walksnail VTX → FC UART3 + ESC 5V pad. Antenna out the back.
10. **Seat the NX module.** Drop the Orin NX 16GB module into the DAMIAO SO-DIMM slot at ~30°, press flat until both retention latches click. Thermal paste + heatsink + screw.
11. **Mount top plate + DAMIAO carrier.** 4× M3×30 alu standoffs from ESC plate up. PETG carrier mount with M3×6. 40 mm cooling fan slots between carrier heatsink and top plate (fan power to one of DAMIAO's GH1.25 2-pin 5V taps).
12. **Wire NX power · XT30 direct.** One XT30 pigtail from ESC PDB 6S pads to DAMIAO's XT30 input. **No external BEC** — DAMIAO accepts 6S directly and bucks internally to 5V. Verify polarity before first power-up.
13. **Wire MAVLink.** Use DAMIAO's stock GH1.25 4-pin UART cable; the four wires are 5V — TX — RX — GND. Crimp/solder the free end to FC UART4: TX↔FC RX4, RX↔FC TX4, GND↔FC GND. *Don't connect the 5V wire to the FC — FC has its own 5V rail.*
14. **Mount camera.** RPi Cam 3 Wide on +20° PETG mount, 22→15-pin ribbon to DAMIAO CSI0. Route away from ESC power leads.
15. **Final pass.** Cable ties, hot-glue connectors, antenna polarization check, battery strap fits. Verify NX SO-DIMM latches still seated.
16. **Bench test.** Props OFF. Smoke check at 6S. BetaFlight Motors tab — all 4 spin correct direction at 5%. NX boots over USB-C (jtop on host laptop).

---

## §07 Power + wiring

```
BATTERY (6S 22.2–25.2 V)
   │
   └── XT60 + Cap 1000µF ──► ESC + PDB (Tekko32)
                                │
                                ├──► 4× Motor (M1-M4, 3-phase)
                                ├──► FC Kakute H7 (9V via VBAT pad)
                                ├──► XT30 → DAMIAO carrier (6S direct, internal buck to 5V)
                                ├──► VTX Walksnail (9V from FC pad)
                                └──► RX ELRS (5V from FC)
```

NX continuous draw at MAXN (25 W) is ~5 A on the 5 V rail. DAMIAO's
internal buck handles this directly from 6S (~22-25V) — no external BEC
needed. The 1000 µF cap on the ESC PDB damps the boot-spike ripple.
If you fall back to a J401 / other desktop carrier, restore the external
5V/6A BEC + an XT30→5.5×2.1 mm barrel pigtail.

### FC pin assignments (Kakute H7 V2)

| Pad/Pin | Connection | Purpose |
|---|---|---|
| UART4 RX/TX | DAMIAO GH1.25 4-pin UART connector (NX UART1) | MAVLink to companion · SET_POSITION_TARGET_LOCAL_NED |
| UART6 RX/TX | ExpressLRS RX | safety pilot, kill-switch |
| UART3 RX/TX | Walksnail VTX | OSD + VTX control over MSP |
| VBAT pad | cap + main lead | 22–25V battery sense |
| 9V pad | VTX + Walksnail cam | 3A budget, FC-regulated |
| BUZZ pad | piezo + to BUZZ, − to GND | lost-drone finder, low-batt alarm. Also wired to v2 PCB watchdog. |
| BOOT pad | DFU recovery only | short to GND during USB plug-in |

---

## §08 Camera mount (+20° tilt)

Spec: VADR-TS-002 §3.8. Camera optical axis at +20° upward from body
X-axis, rotation about body Y. Intrinsics fx=fy=320, cx=320, cy=180.
Image 640×360, HFoV 90°.

Mounted on a printed PETG wedge that locks the lens at the spec angle.
Body origin = camera origin (no translation offset).

---

## §09 Firmware · BetaFlight 4.5

1. Install BetaFlight Configurator 10.10+ on dev laptop
2. Short BOOT pad to GND, plug USB → DFU mode
3. Target: `HOLYBRO-KAKUTEH7-V2` (check silkscreen for rev)
4. Flash latest stable, full chip erase, reboot
5. Paste CLI dump from build-guide v3 (sets DSHOT600, RPM filter, ELRS, MAVLink on UART4)
6. Calibrate accel + gyro (drone level on bench)
7. Save + reboot, power-cycle to verify

**Do not arm without props off.** First bring-up is highest-risk moment.

---

## §10 Companion compute · Jetson Orin NX 16GB

The NX shares its SO-DIMM 260-pin pinout with the Orin Nano — SDK Manager
images run on either. The differences that matter: **2× memory** (16 GB
vs 8 GB · headroom for planner cache + EKF history), **1.5× compute** (100
TOPS vs 67 TOPS at MAXN · the YOLO11n-pose + segmentation + perception-aware
PPO observation pass all fit inside the 33 ms frame budget at 25 m/s
ATTACK profile), and **~67 % more power** (25 W vs 15 W MAXN · the reason
we sized the BEC to 6 A).

1. Flash JetPack 6.2+ to NVMe via NVIDIA SDK Manager — NX + DAMIAO in **recovery mode** (REC↔GND jumper while USB plug-in)
2. Boot, set hostname `aigp-rig-01..04`. Disable cloud-init dialog, enable SSH
3. Install: `python3-pip python3-dev libgstreamer1.0-dev libcamera-dev v4l-utils mavlink-router`
4. IMX708 driver: install upstream overlay (NVIDIA forum thread B-15924, same as Nano). Confirm with `v4l2-ctl --list-devices`
5. mavlink-router from FC UART (`/dev/ttyTHS1`) → onboard UDP :14550
6. Clone AIGP repo, install conda env, run `python race/onboard/runner.py --rig=01`. Re-compile TensorRT engines for NX architecture with `trtexec` if your host built them for Nano.
7. Set NX to MAXN mode: `sudo nvpmodel -m 0` (mode 0 = 25 W on NX; mode 1 = 15 W; mode 2 = 10 W)
8. **Active cooling required** — 40 mm fan must run continuously. Without it the NX hits thermal throttle at 87 °C in < 60 s under sustained 25 W load.

---

## §11 First-flight checklist

| # | Check | Pass condition |
|---|---|---|
| 1 | Visual inspection | no loose props, no exposed solder, no pinched wires |
| 2 | Props OFF · motor direction (BetaFlight Motors tab) | each motor matches frame layout |
| 3 | Props OFF · RC stick mapping | throttle/sticks correct in Receiver tab |
| 4 | Battery voltage at startup | > 24.8V (6S full) |
| 5 | Failsafe arm test | TX off → motors disarm < 1s |
| 6 | NX boot on DAMIAO · CSI camera | `v4l2-ctl --list-devices` shows imx708 |
| 7 | Onboard MAVLink heartbeat | NX sees FC heartbeat ≥ 2Hz |
| 8 | NX cooling fan running | tachometer or fingertip airflow check at 5V tap |
| 9 | Short hover · manual (indoor + net) | safety pilot can hover stable |
| 10 | Hover-attitude trim | < 1 m/s drift in calm air |
| 11 | Short hover · onboard autonomy (loiter) | no runaway/oscillation, < 30s |
| 12 | Short gate approach · autonomy | detector locked, altitude held |
| 13 | Kill-switch drill | pilot can disarm mid-flight |
| 14 | Post-flight thermal | NX heatsink warm not hot · motors warm · ESC not smoking |
| 15 | Battery temp | < 45°C at landing, storage charge if > |

---

## §12 Tuning notes

Default BetaFlight 5″ 6S PIDs are fine. Three deviations for this build:

1. **D-term LP → 100 Hz.** NX carrier on top plate adds inertia.
2. **Yaw P +10%.** CoG shifted forward by NX + tilted cam.
3. **Throttle expo +20.** Smoother stick→motor for hover trim.

RPM filter on (default with BLHeli_32 + bidirectional DShot). If motors
get noisy after a crash, balance the props before re-tuning.

---

## §13 Maintenance & spares

| Component | Consumed at | Stock |
|---|---|---|
| Propellers | 1 set / 30 min or any contact | 10 sets · $50 |
| Motors | ~3-4 crashes or sand ingress | 4 spare (one set) |
| Frame arms | per hard crash | 1 spare set |
| FC | rare, survives if dry | 1 spare team-wide |
| ESC | burnout on stuck prop | 1 spare team-wide |
| Battery | ~150 cycles to puffy | 2 fresh per drone |
| RPi Cam | rare, lens-down impact only | 1 spare team-wide |
| DAMIAO carrier | rare, but $50 each · cheap insurance | 1-2 spare team-wide |
| NX module | rare, but $699 each · careful! | 1 spare team-wide |
| 3D-printed mounts | per crash | reprint on demand |

---

## §14 Purpose · sim-to-real bridge

The DIY rig exists specifically to capture ~30 minutes of real-flight
telemetry for the residual-dynamics model.

- ~10 min indoors, netted space · lightweight gate mockup · low speed
- ~15 min outdoors, daylight · dusk · shadow
- ~5 min high-dynamic · banking · recovery

**This is not a race drone — it's a data-capture tool.** Optimize for
reliability + predictable dynamics, not top speed.

---

## §15 Flight PCB v2 · custom carrier (stretch goal)

**Status update · 2026-05-27.** The current build (DAMIAO V1.1 above)
already lands on most of what we'd design ourselves: drone form factor
(87 × 50 mm, 36 g), XT30 6S direct input, JST-GH MAVLink, M.2 NVMe.
The v2 custom PCB stays on the roadmap but is **no longer urgent** —
we'd build it only if we hit one of these gaps:

- **On-board watchdog MCU** — DAMIAO has no failsafe peripheral; if the NX brown-outs or thermal-trips, the FC has no way to know unless we add an STM32 sniffing the 5V rail.
- **Stack-pattern footprint** — DAMIAO is 87 × 50 mm; matching the standard 30.5 × 30.5 mm FC stack pattern would let us drop the dedicated PETG carrier mount entirely.
- **Shielded CSI/MAVLink routing** — DAMIAO's connector placement is fine for IoT, but for racing we'd want CSI and MAVLink on opposite edges to keep ESC EMI off the camera lanes.

If we end up doing a v2 PCB, the design targets below describe what it
would look like. **Otherwise the DAMIAO V1.1 is good enough for the
sim-to-real bridge and the first competition season.**

### Design targets

| Spec | Target | Why |
|---|---|---|
| Footprint | 60 × 35 mm · 30.5 × 30.5 mm mount | Fits FC stack pattern · drops into top-plate aperture |
| Module socket | SO-DIMM 260-pin (Foxconn AS0B226-S43B-7F) | Same as J401 · accepts Nano/NX |
| Input voltage | VBAT direct · 14–25 V | No external BEC |
| 5 V rail | Integrated buck · 8 A · TPS54824 or LMR16030 | 25 W NX + boot spike + camera + fan + USB |
| Backup 3.3 V | LDO from 5 V · 500 mA | Watchdog MCU |
| MAVLink port | 4-pin JST-GH · 3.3 V TTL UART · ESD-protected | Direct to FC UART4 · no jumper |
| Camera | 15-pin CSI-2 + 22-pin CSI-2 | RPi Cam 3 + stereo upgrade later |
| M.2 slot | M.2 2230 NVMe (PCIe x1) | OS + dataset cache · 2280 too long for 60 mm board |
| USB | 1× USB-C OTG (debug) · 1× USB 2.0 header | OTG for SDK Manager · header for occasional dongle |
| Status LEDs | power · NX heartbeat · MAVLink rx | Visual triage on the pad |
| Watchdog MCU | STM32G030 monitors 5 V + boot + temp · pulses FC BUZZ | Save a $1,750 walk on brown-out / thermal trip |
| Mounting | 4× M3 · 30.5 × 30.5 mm pattern · 8 mm corner relief | FC-pattern stack-compatible |
| Target mass | **≤ 18 g** bare PCB · ~98 g total with module + heatsink | Saves ~32 g vs J401 + external BEC + harness |

### What we keep vs. drop from J401

| Feature | v2 PCB | Why |
|---|---|---|
| SO-DIMM 260-pin socket | **keep** | Whole point |
| M.2 2280 NVMe | shrink → **2230** | 2280 needs 80 mm of board; 2230 fits in 30 mm |
| 15-pin CSI-2 | **keep** + add 22-pin | RPi Cam today, stereo later |
| 40-pin RPi GPIO header | **drop** | Replace with dedicated 4-pin JST-GH for MAVLink |
| USB-A ×4 | cut to **USB-C OTG + 1 USB-2 header** | Most were for desktop dev |
| Dual HDMI | **drop** | No display on a drone |
| RJ45 gigabit | **drop** | WiFi via M.2 covers anti-cheat internet |
| External barrel jack | replace with **VBAT XT30 input** | One pigtail · no external BEC |
| No watchdog | add **STM32G030 watchdog** | Brown-out / thermal trip → FC BUZZ → auto-LAND |

### Development plan

1. **Reference design study** — NVIDIA Orin Nano/NX SO-DIMM Carrier Reference (DA-10797-001) + Foxconn AS0B226 mech drawing
2. **Schematic** in KiCad 9. Critical: PCIe x1, CSI-2 lanes, UART1, USB3.0, VDD_5V, power-good
3. **Power chain** — 6S → 5V/8A buck in TI WEBENCH. ≥ 92 % efficiency at 4 A typical
4. **Layout** — 4-layer · CSI ≤ 50 Ω differential · matched-length ±5 mils · analog GND island under buck
5. **Prototype** — JLCPCB / OSH Park · 5 boards + stencils · hand-place SO-DIMM (1.0 mm pitch)
6. **Bring-up** — power into VBAT input, no module · verify 5 V rail under 4 A load · verify 3.3 V LDO · watchdog boots
7. **Module test** — seat NX, flash JetPack via USB-C OTG, confirm UART1 + CSI0 + M.2
8. **Flight test** — drop into a Nazgul5, fly the racing-doctrine pipeline end-to-end

### Vendor option (don't roll our own)

[Auvidea JN31](https://auvidea.eu/?s=JN31) (87 × 55 mm) and
[Forecr DSBOARD-NX-LT](https://forecr.io/products/dsboard-nx-lt)
already strip desktop ports and integrate a buck. ~$280 each — about 2×
the J401 but a third the work of a custom board. The PCB v2 plan only
beats them on integrated MAVLink and watchdog.

---

## How to use this with Claude

Drop this file into a chat with Claude (Claude.ai or Claude Code) and you
can ask things like:

- *"What's the total cost if I want to build two of these?"*
- *"Walk me through the wiring step by step."*
- *"Trade-offs between J401 and the v2 flight PCB?"*
- *"Which props should I buy for outdoor windy conditions?"*
- *"Generate a packing checklist for a 4-hour field session."*
- *"What's the failure mode if the NX browns out?"*
- *"Convert this BOM into a Google Sheets-friendly CSV."*

Claude will use this doc as ground truth for the build.

---

*Generated 2026-05-27 · DIY-5INCH v4.0 · Archer-class clone · Orin NX migration*  
*Source: https://aigp-dashboard.pages.dev/documents/diy-5inch-racer-build*