All-in-one (AIO) flight-controller boards have matured rapidly in the last two years, shrinking entire powertrains into a single 25.5 × 25.5 mm PCB. While that trend has enabled ultra-compact drones, it also forces designers to balance thermal limits, signal integrity and repairability. One model that has drawn steady attention is the SpeedyBee F405 AIO Bluejay 40 A, a compact board claiming big-stack capability without the big-stack footprint. In this article we assess its technical merits, benchmark results and realistic trade-offs—so you can decide if it belongs in your next sub-250 g cruiser or 5-inch ultralite project.
1. What Is the speedybee f405 aio Bluejay 40 A?
At its simplest, the board combines an STM32F405 micro-controller, an onboard barometer, six hardware UARTs and a four-in-one 40-amp ESC that ships with Bluejay 0.22 firmware. The 25.5 mm mounting format, direct USB-C connector and soft-mounted gyroscope target modern toothpick frames, tiny whoops and weight-conscious 5-inchers alike.
2. Core Highlights
- 40 A continuous / 45 A burst ESC rated for 3–6 S, covering anything from 2.5-inch props to lightweight 210 mm builds.
- Bluejay firmware pre-flashed, enabling bi-directional D-shot and RPM filtering without a separate license.
- Onboard Wi-Fi / Bluetooth chip integrated with the SpeedyBee mobile app, allowing field configuration and log download.
- Dedicated 6 pin HD VTx plug (ground / VBAT / TX‑RX / 5 V / 9 V) for quick connection to Walksnail Avatar, DJI O3 or HDZero.
The goal is to deliver “big stack” features in a single PCB while keeping the assembly below 15 g.
3. Where to buy
3.1 Discover MEPSKING: Your Premier One-Stop Shop for FPV Drone
MEPSKING is a leading online platform dedicated to FPV drone enthusiasts. As a trusted industry leader, MEPSKING bring you an extensive range of high-quality FPV drones and accessories, making it easier than ever to find everything you need for your next flight adventure.
At MEPSKING, we’ve partnered with top-tier brands like DJI, T-MOTOR, iFlight, BETAFPV, RunCam, CaddxFPV, RADIOMASTER, SpeedyBee and more to provide a wide selection of FPV essentials. From motors, ESCs, frames, and cameras to FPV goggles, controllers, and beyond, we’ve got you covered.
Plus, our exciting ongoing events make shopping even more rewarding:
- Spin the Lucky Wheel-Win exclusive prizes and discounts.
- Free Product Trials-Test our products at no cost.
- Social Media Events-Engage with us on our official channels for a chance to win.
3.2 Why Choose MEPSKING: Official Quality Assurance, More Affordable Prices
A Complete Product Range: We offer both variety and quality.
- All FPV Essentials in One Place: Find everything you need, from motors, ESCs, and flight controllers to goggles, antennas, and video transmitters.
- Top-Quality Selection: Partnering with leading brands, we curate the most popular and reliable products on the market. Every product undergoes professional testing by our team to ensure quality.
Dual Quality Assurance
- Brand Warranty: Enjoy coverage directly from the manufacturers.
- MEPSKING Support: Our professional after-sales service includes a two-year warranty on all orders, ensuring any quality issues are promptly addressed.
Unbeatable Prices
- Official Discounts: Take advantage of brand promotions.
- Exclusive MEPSKING Offers: Stack additional platform discounts on top of official deals for maximum savings.
Faster Delivery
We prioritize getting your products to you quickly so you can spend less time waiting and more time flying.
3.3 Don’t Miss Out on Free Trail at MEPSKING!
From the 16th to the 21st of every month, MEPSKING offers an exclusive Free Trial Program featuring different products each time. From motors and ESCs to flight controllers and more, you’ll have the chance to test premium FPV gear for free. Don’t wait—explore this month’s lineup and take your FPV experience to the next level!
4. Key Specifications at a Glance
| Feature | Data Point |
| MCU | STM32F405 @ 168 MHz |
| Gyro | ICM‑42688‑P, 32 kHz capable |
| Max LiPo Voltage | 6 S (25.2 V) |
| ESC Firmware | Bluejay 0.22 (BLHeli‑S fork) |
| Continuous / Burst Current | 40 A / 45 A |
| UARTs | 6 hardware + soft‑serial option |
| Blackbox | 16 MB SPI flash |
| Barometer | BMP388 |
| OSD | AT7456E (analog) + MSP‑DisplayPort (digital) |
| Integrated BECs | 5 V @ 2 A, 9 V @ 1.5 A, 3.3 V @ 0.5 A |
| Weight | 14.8 g including gummies |
5. Design Philosophy: A Holistic Take on Heat & Noise
AIO boards live or die by thermal management and signal hygiene. SpeedyBee’s design team took several measures:
- Copper Weight Optimization: Two‑ounce outer layers help dissipate MOSFET heat without resorting to a heavy cast-aluminum heat spreader.
- Segregated Ground Planes: Sensor and gate‑driver grounds are isolated until the star-ground point near the battery pad, reducing ESC switching noise in gyro traces.
- Shielded Oscillator Can: The 8 MHz crystal sits under a stamped RF can, lowering phase jitter—subtle, but it contributes to cleaner gyro raw data.
- Urethane Conformal Coating: A thin protective film guards against coastal corrosion yet remains re-solderable with a 350 °C iron.
These touches aim to make the board behave more like a two-layer stack rather than a thermal bottleneck.
6. Firmware & Configuration Workflow
Because it is still an F405, firmware support is mainstream:
- Betaflight 4.5+ — Board definition auto‑detects all ports; presets for 7‑pole or 14‑pole motor types install via the SpeedyBee app in under five minutes.
- INAV 8.x — GPS + barometer navigation works once UART5 is remapped; the barometer sits on I²C for lower CPU load.
- ArduPilot (Copter 4.5) — Community targets report 4 kHz / 1 kHz loops stable; faster loops tax the F4 but remain flyable up to 6 S.
- Bluejay enables 48 kHz PWM and dynamic PWM frequency scaling, which trimmed idle current by 6–8 % in bench tests.
7. Bench Results & Flight Tests
7.1 5-Inch Ultralite (6 S)
Running 2203.5 × 1850 kV motors and HQ 5×2.5 props on a 620 g AUW rig, blackbox logs showed:
- Max battery current 95–100 A during full‑stick punchouts
- MOSFET temps plateaued at 73 °C after a 45‑second hover in 28 °C ambient
- Gyro noise floor averaged 0.002 d/s² (ICM‑42688) — no additional soft‑mounting needed
7.2 3.5-Inch Toothpick (4 S)
With 2004 × 3000 kV motors and 3520 tri‑blade props:
- Overall AUW = 243 g including DJI O3
- Board temp seldom exceeded 55 °C
- Bluejay’s dynamic idle kept minimum throttle under 4 %, aiding low‑angle cinematic shots
7.3 2.5-Inch Cine-Whoop (4 S)
Enclosed ducts often trap heat. On a 180 g build, continuous indoor hover pushed ESC temps to 80 °C after eight minutes. A 20 mm duct vent remedied airflow, underscoring the predictable heat limits of any AIO board.
8. How the SpeedyBee F405 AIO Stacks Up in 2025
| Metric | SpeedyBee F405 AIO | JHEMCU GHF405 Pro | GEPRC Taker F722 AIO |
| MCU | F405 | F405 | F722 |
| ESC Amps | 40 A | 45 A | 35 A |
| Firmware | Bluejay | Bluejay | BLHeli‑32 |
| On‑board Wi‑Fi | Yes | No | No |
| Blackbox | 16 MB | 8 MB | 16 MB |
| Barometer | Yes | No | Yes |
| Price (USD, Q2‑25) | ≈75 | ≈68 | ≈92 |
The board trades a modest 5 A of headroom relative to the JHEMCU unit for integrated wireless tuning, a barometer and cleaner gyro traces. Against premium F7 AIOs it saves cost but shares the F4 CPU ceiling.
9. Who Should Consider This Board?
- Lightweight 5‑inch pilots looking for a single‑PCB solution under 15 g yet still comfortable at 6 S.
- Cinematic shooters who value barometer altitude data for smoother Auto‑Level or INAV cruise modes.
- Field builders who often solder repairs at events and appreciate the direct USB‑C plus clearly labeled pads.
10. Potential Drawbacks to Note
- F4 Processing Limits: Loop times beyond 4 kHz gyro / 2 kHz PID eat 85–90 % CPU; F7 boards remain the pick for ultra‑low‑latency racing.
- Thermal Ceiling: Continuous current above 35 A for extended freestyle can accumulate heat; consider external airflow in cine‑whoops.
- Single‑board Failure Mode: A burnt BEC takes down FC and ESC simultaneously, unlike modular stacks where only one half may fail.
11. Risk Mitigation Tips
- Constrain PWM frequency to 48 kHz for sport quads; 96 kHz offers softer throttle but doubles switching losses.
- Add a 20 × 20 mm copper shim under the ESC corner on frames with limited air throughput.
- Flash Bluejay 0.23‑Alpha to enable dynamic motor timing; early tests show a 3 % reduction in peak ESC temperature.
12. Final Thoughts
The speedybee f405 aio Bluejay 40 A blends convenience and capability by folding a 6 S‑ready ESC, barometer, Wi‑Fi / Bluetooth telemetry and 16 MB blackbox into a 25.5 mm square beneath the 15 g mark. It is not engineered to dethrone high‑end F7 AIOs in raw computational headroom, nor can it defy the physics of heat in a one‑board layout. Yet for many freestyle and cinematic pilots who need a tidy build envelope without surrendering UART count or sensor fidelity, SpeedyBee’s latest all‑in‑one remains a balanced and serviceable choice for 2025.
Your ultimate decision should align with the mission of the craft: amperage draw, expected airflow, firmware preference and repair philosophy. Evaluate those variables, and the right choice—AIO or stack—will usually reveal itself before you even power on the soldering iron.
Also Read-Kickstart Your Tech Career with a Diploma in Information Technology at Sigma
