The DJI O4 Professional Air Unit is incredible, however one main draw back is its weight. At 33g, it’s not best for micro quads or builds that intention to remain beneath the 250g weight restrict.
That’s why the “bare” DJI O4 Professional has been one of the vital anticipated improve within the FPV passion. A “bare O4 Professional” primarily removes the unique housing and heatsink, changing them with a minimal aluminium bracket, decreasing weight by 42%!
After taking a better take a look at the WalleFPV Bare O4 Professional, I’ve to say it’s extremely engineered. It’s clear lots of thought has gone into the design, and the extent of weight saving is spectacular. Nevertheless, it does introduce a number of trade-offs that you must take into account earlier than utilizing it, which I’ll cowl on this overview.
New to the DJI FPV system?
The place to Purchase
Get the WalleFPV Bare O4 Professional Air Unit from:
You too can simply purchase the improve package and modify your personal O4 Professional:
The package comes with these equipment
- M1.5 hex screwdriver
- Phillips screwdriver
- A bag of spare screws
- Two micro 5.8GHz antennas
If you are going to buy the total bare O4 Air Unit, it would additionally embrace the unique housing and antennas. There’s additionally a 6-pin cable for connecting the Air Unit to the flight controller (not proven within the image). That is the usual cable that comes with the unique O4 Professional.
The Professionals and Cons of Bare O4 Professional
Professionals
Extremely light-weight
The unique DJI O4 Professional weighs round 33g, whereas the Bare O4 Professional is available in at just below 19g — a 14g discount. This considerably improves flight efficiency and effectivity of your FPV drone, making it best for micro quads, sub-250g builds, and long-range drones.
Drop-in compatibility
The Bare O4 Professional makes use of the identical mounting sample for each the digicam and transmitter module as the unique air unit, making it appropriate with current frames and BNF drones. For current setups, it’s primarily a plug-and-play improve.
Extra compact design
It’s barely smaller than the unique, permitting it to suit into tighter builds.
Identical performance
You get the very same options and efficiency as the unique DJI O4 Professional.
Cons
Cooling is a significant concern
From my testing, the Bare O4 Professional is rather more liable to overheating with out enough airflow. It’s not best for enclosed frames or floor autos the place airflow is restricted.
Decreased sturdiness
Though the brackets are created from 6061 aerospace-grade aluminium (in response to WalleFPV), the PCB is way extra uncovered in comparison with the inventory housing. This makes it extra weak to crashes and environmental injury. You would possibly need to take into account including conformal coating for water resistance: https://oscarliang.com/waterproofing-drone-electronics/
ND filter compatibility
The unique DJI ND filters now not match. You’ll want to make use of WalleFPV’s customized ND filters. Alternatively, you possibly can reinstall the unique digicam housing if you wish to maintain utilizing DJI filters.
Guarantee void
Modifying your DJI O4 Professional will void the DJI guarantee.
Measurement & Weight Mesurements and Comparability
Weight Breakdown
| Unique O4 Professional | Bare O4 Professional | |
| Digital camera Module (with cable) | 11.05g | 8.84g |
| Transmitter Module (no antennas) | 17.33g | 9.14g |
| Antennas | 4.16g | 0.87g |
| Complete Weight | 32.54g | 18.85g |
You too can combine and match antennas or digicam modules relying in your wants.
Dimensions
| Unique O4 Professional | Bare O4 Professional | |
| Digital camera cable size | 13cm | 15cm |
| Digital camera width | 20mm | 20mm |
| Digital camera mounting | 2x M2 Holes 16mm Aside | Identical |
| Transmitter measurement (WxLxH) | 33.5×33.5×13.3mm | 31.4×31.4x12mm |
| Transmitter mounting | 20x20mm & 25.5×25.5mm | Identical |
The mounting is actually an identical, so it’s appropriate with current O4 Professional builds.
The longer 150mm cable is nice for 5-inch and long-range drones. A shorter 60mm cable can also be accessible, which is good for micro builds (2-inch and smaller).
Construct Particulars
Putting in the Bare O4 Professional is a breeze.
With authentic O4 Professional, my Flywoo Explorer weighs 166g:
With the Bare O4 Professional it now weighs solely 152g!
WalleFPV has gone to nice lengths to scale back weight—even utilizing aluminium screws to shave off each potential gram.
Left: Unique housing screws; Proper: Bare O4 Professional Screws
Connector is held securely utilizing tiny Philip screws.
It’s this degree of consideration to element that makes the burden discount so spectacular, but it surely additionally highlights the trade-off: sturdiness and thermal efficiency take successful.
Overheat Testing
With the heatsink eliminated, we count on the Air Unit to overheat extra rapidly—so let’s check it.
Check Circumstances
- Ambient temperature: 20°C
- No airflow (indoor bench check)
- Quad armed (Air Unit transmits at full energy 1200mW)
- Bitrate: 60Mbps
- VTX Onboard Recording: 4K 60fps
Outcomes
Unique O4 Professional
- Overheat warning: 2 minutes
- Air Unit Shutdown: By no means (inside the 10-minute check)
WalleFPV Bare O4 Professional
- Overheat warning: 40 seconds
- Air Unit Shutdown: 2 minutes
When the overheat warning seems, the Air Unit makes an attempt to scale back temperature by:
- Stopping onboard recording
- Dropping bitrate to 30–40Mbps
- Lowering transmission energy
If the temperature continues to rise, the Air Unit will ultimately shut down to forestall {hardware} injury—leading to full lack of video sign.
Actual-World Implications
Bench testing represents the worst-case situation as a result of there’s no airflow.
When you find yourself flying:
- Airflow considerably improves cooling
- Overheating is much less possible even with out heatsink
This has been confirmed with the bare DJI O3 Air Unit which I examined extensively. So long as there’s first rate airflow it shouldn’t be a difficulty.
Nevertheless, the outcomes clearly present that the Bare O4 Professional overheats a lot quicker as a result of lack of a heatsink. Thermal administration turns into crucial.
My Sensible Recommendation
From my testing, right here’s what I like to recommend:
- Use decrease VTX energy for short-range flying, or use Auto Energy
- Keep away from leaving the quad powered on the bottom for too lengthy, take off as quickly as potential after plugging within the battery
- In scorching climate, all the time do a brief check flight close by first, to ensure your bare O4 can deal with it earlier than flying too distant
ND Filters
When you take away the unique digicam housing, the inventory DJI ND filters are now not appropriate.
You’ll want WalleFPV’s devoted filter set:
Included Filters
Even in the event you don’t use ND filters, I nonetheless suggest placing the UV filter on—it acts as a lens protector.
Additional Studying: Why ND filters are helpful to picture high quality: https://oscarliang.com/nd-filter-fpv/
Bare O4 Professional vs O4 Lite
With none modifications, the O4 Professional is clearly superior in picture high quality.
However issues change while you add a wide-angle lens to the O4 Lite. Take a look at my overview right here: https://oscarliang.com/flywoo-o4-wide-angle-lens-new/
However relating to weight, the O4 Lite now not has the clear benefit over the Bare O4 Professional:
- O4 Lite + Broad Angle lens: 15g
- Bare O4 Professional: 19g
For micro quads (just like the 1S Flywoo Firefly18), that 4g weight distinction nonetheless makes a giant distinction.
And take into account the value distinction:
- O4 Lite + Broad Angle lens: roughly $170
- Bare O4 Professional (DIY): roughly $260
With that mentioned, the O4 Lite merely can not match the O4 Professional digicam relating to picture high quality, which encompasses a 1/1.3-inch sensor (higher dynamic vary and low gentle), 4K/120fps recording, a 155° ultra-wide-angle lens and 10-bit D-Log M colour mode—all crucial options the O4 Lite digicam lacks.
Improve
If you wish to convert your personal O4 Professional, you possibly can observe this information: https://drive.google.com/file/d/1wmJ15Pm2PHmTLj2q3AZpOceW6Ngzxk88/view?usp=sharing
Conclusion
The WalleFPV Bare O4 Professional is precisely what many FPV pilots have been ready for—a approach to carry the total efficiency of the DJI O4 Professional into light-weight builds.
The ~14g weight discount is very large, particularly for sub-250g micro drones and lengthy vary builds. And the engineering behind this package is genuinely spectacular.
Purchase the WalleFPV Bare O4 Professional Package right here:
Nevertheless, this comes with actual trade-offs:
- Considerably lowered cooling efficiency
- Elevated fragility
- Lack of compatibility with authentic ND filters
From my expertise, this improve makes essentially the most sense if:
- You prioritize weight and efficiency
- You don’t crash loads
- Your drone has first rate airflow to the air unit
When you’re constructing a high-performance light-weight quad with DJI O4 Professional, that is simply one of the vital impactful upgrades you can also make. However in the event you’re flying in scorching climates, your drone has an enclosed body, otherwise you crash loads, you’ll must be additional cautious with this hack.
