Web Tool Cranks Up The Power On DJI’s FPV Drone

Apparently, if the GPS on your shiny new DJI FPV Drone detects that it’s not in the United States, it will turn down its transmitter power so as not to run afoul of the more restrictive radio limits elsewhere around the globe. So while all the countries that have put boots on the Moon get to enjoy the full 1,412 mW of power the hardware is capable of, the drone’s software limits everyone else to a paltry 25 mW. As you can imagine, that leads to a considerable performance penalty in terms of range.

But not anymore. A web-based tool called B3YOND promises to reinstate the full power of your DJI FPV Drone no matter where you live by tricking it into believing it’s in the USA. Developed by the team at [D3VL], the unlocking tool uses the new Web Serial API to send the appropriate “FCC Mode” command to the drone’s FPV goggles over USB. Everything is automated, so this hack is available to anyone who’s running a recent version of Chrome or Edge and can click a button a few times.

There’s no source code available yet, though the page does mention they will be putting up a GitHub repository soon. In the meantime, [D3VL] have documented the command packet that needs to be sent to the drone over its MODBUS-like serial protocol for others who might want to roll their own solution. There’s currently an offline Windows-only tool up for download as well, and it sounds like stand-alone versions for Mac and Android are also in the works.

It should probably go without saying that if you need to use this tool, you’ll potentially be violating some laws. In many European countries, 25 mW is the maximum unlicensed transmitter power allowed for UAVs, so that’s certainly something to keep in mind before you flip the switch. Hackaday isn’t in the business of dispensing legal advice, but that said, we wouldn’t want to be caught transmitting at nearly 60 times the legal limit.

Even if you’re not interested in fiddling with drone radios, it’s interesting to see another practical application of the Web Serial API. From impromptu oscilloscopes to communicating with development boards and conference badges, clever developers are already finding ways to make hardware hacking easier with this new capability.

[Thanks to Jules for the tip.]

21 thoughts on “Web Tool Cranks Up The Power On DJI’s FPV Drone

  1. Radio spectrum is a precious shared resource. Even perfectly legal radio devices can cause problems for other radio devices (e.g. as more people install home WiFi routers, neighborhood WiFi gets worse). Publicizing software that turns law-abiding devices into law-breaking devices hurts everybody. Hackaday is already awesome. Does it really need to “go to the dark side” to stay relevant?

    1. Maybe the title should have focussed on Web Serial API since GPS spoofing is just one of the things you can do. Might have been more Hackaday-ish to focus on the “impromptu oscope” or dev board/badge twiddling.

    2. I am curious just how much range people are normally getting at the 25 mW. level.

      I agree, radio is a precious shared resource but it with limits like that it sounds like somebody else already isn’t sharing. Not every law is a good law!

      i am glad that this time HaD actually mentions that it is illegal. People can make up their own minds where to go from there and get busted too if they are dumb about it. I wish this was brought up with all those WiFi range extension projects that used to be so popular. I really don’t like articles that tell people how to do an illegal thing but don’t bother telling them that it is an illegal thing.

      Speaking of WiFi extension, have people just stopped doing that or is it all just such old news that nobody talks about it anymore?

      1. For those living in free democratic countries (all EU nations being an example), if there is a bad law then people need to petition and convince their representatives to change the law.

        A system where each person obeys only the laws they feel are right is going to be chaos, and a bunch of people who don’t have the resources to fight are going to get slapped with costly fines and imprisonment even though they believe they are in the right.

        No doubt I think the EU needs to cede control of the airwaves back to individuals. The longer it sits in the hands of annointed organizations and corporations with near limitless resources, the less the airwaves are a shared resources for the public and the more it is a commodity to be bought and sold.

        1. I think that is the idea behind limiting the transmitter power. If you think of transmitter power as “volume” in an accustical sense, it doesn’t make much sense to have people that live in close proximity to one another always be screaming. By illegally increasing your own transmitter power you might get a few KM more range, but you are also interfering with everyone else who would want to use those frequencies, and probably well beyond the distance that you are actually flying.

          1. @Tad Pole, I think before you make comparisons to screaming you need to answer my question.

            “I am curious just how much range people are normally getting at the 25 mW. level.”

            I’m not a drone user (yet) but I have played quite a bit with radio and not counting data modes that are best measured in words per hour I’m not aware of anything that actually works at 25mW. I would guess a better analogy would be people limited by law to whispering at their quietest with two pillows stuck over their faces trying to take the pillows off when big brother isn’t looking.

            But again, not a drone user yet. So why not answer the question before acting like it has already been answered?

            Or maybe it’s that playing all day with a drone that barely leaves your arms’ reach sounds like a good time to you?

            @jonmayo – Yes, it is totally realistic to think that one can get enough of the general public interested in the radio power of rc drones to actually make a difference with a petition. May I come live in your world? The real one really sucks in comparison.

            @All – TFA says “most” EU countries are limited to 25mW. I guess that implies some aren’t? And do I need to update my map or does our planet still have more than just the US and the EU on it? Might someone be using this to get access to power levels that they do have a legal right to use but EU stinginess and manufacturer laziness has robbed from them?

            And who’s to say that someone with an amateur license won’t combine this hack with one to transmit a callsign and do this on a ham band legally? Seriously, if you don’t like hacks I’m sure there is a good crafting site out there for you.

      2. There aren’t many projects now that commercial solutions and ubiquitous cellular service have reduce the need for creating such projects and only the people who really want to understand how it all works are doing it now.

        In many situations, the commercial products are easier and cheaper than trying to do it yourself (even without factoring in the value of your time).

        1. If you live somewhere that the price of cellular service isn’t higher than the necessities (gas, electric and water combined) then you are very lucky but should realize we aren’t all so lucky.

          Unless you feel confident using one of those really low cap hobbyist services. You know, where it only costs a few bucks but if you go over the limit (measured in MB) they come take your house, your car and your family away.

          I mean, you probably won’t go over just sending control signals. So long as you weren’t hoping for FPV. But if you do manage to go over.. well maybe you can have a home again in the next lifetime.

    3. Laws are not perfect, same as this CE limit imposed need more work. Not all countries are the same and have same needs.
      How is flying in middle of woods or in field interfering with any wifi signal?

  2. Web serial API. Pfeh. The browser talking to *my* serial port (mine, because I paid for it, dammit!).

    What’s next? Google’s browser (because it’s not mine, mind you!) talking to my Koi [1]?

    I try to keep my hardware as “out of reach” for the browser as I practically can. I consider the browser as an Implant of the Evil and treat it like that.

    [1] https://en.wikipedia.org/wiki/Koi

    1. Yeah, web browsers being able to directly access hardware seriously worries me. That sort of thing is why I compile my browser instead of using the released binaries, in the compiled version, I can configure out all the random stuff I don’t like (The direct GPU stuff has caused a lot of problems for me, and I don’t trust the DRM code making direct calls to undocumented parts of my CPU…). Yeah, there are section of the internet that are inaccessible to me now, but those were the parts I never cared about anyway (And usually the parts that are massive performance hogs anyway)

    2. I also wonder about these types of proposed web standards, such as this one, usb, bluetooth, battery, etc. There are a lot of weird ones that Google likes to introduce. Back when there were competitors, they’d often push back. I wonder how much of it is to support Chrome OS specifically.

      If you get a chance, browse the Web APIs section on MDN. There are some really bizarre ones like barcode detection, payment request, picture-in-picture (that’s actually different from Firefox’s built-in feature!), ambient light events, and more!

      Although I share your general sentiment, I do think it was cool that people could write web apps that could do things like flash arduino-like devices and things of that nature. It kicks the responsibilities for cross-platform support for such tools down the road a bit, lowers the barrier to entry for hobbyists and children just starting out, and it allows you to work with hardware on locked down platforms like school laptops and library computers without needing permission to install special software.

  3. Now I’m waiting on this project to be picked up by a country’s radio authorities and used as a justification for banning drones altogether. Or forcing even more hardware on the drones themselves. Really, this project should have gone the way of extending the Geo-location system so it could increase the power to the legal limits of the nation it is operating in (Although probably would want to factor in a buffer for operating near borders lest you accidentally cross over to a nation with a lower max power and end up losing control of the drone because while the old power level left another 100 meters of range, but the new power level means you’re suddenly 20 meters short…

  4. > A system where each person obeys only the laws they feel are right is going to be chaos

    This is the case across the whole world. Whether the law is just or unjust, whether it is an infraction, misdemeanor or felony – most people follow the laws they wish to, and disregard the rest.

    In the US, the historical examples that are now laughable to most would include consumption of alcohol, private possession of gold, abortions, use/possession/distribution of marijuana, engaging in homosexuality or adultery, criticizing the government, etc. Even such simple laws as speeding are disregarded as a matter of course in many places.

    I’m sure Europe and the rest of the world have their own examples.

    Legality is, in large part, irrelevant to reality.

  5. The thing that often gets neglected in these discussions is that the relation between transmitter power and usable range is not linear, especially when there is a clear line of sight between the receiver and transmitter.

    You don’t need to kick it up to full power to get the maximum usable range. The maximum usable range in this case will primarily be a function of: (a) transmitter power. (in dBm) (b) free space path loss. (in dB) (c) receiving and transmitting antenna gains and gain patterns (in dB) (d) the minimum usable signal level (in dBm) of the video mode itself.

    The tendency to use the maximum available power regardless of need has actually increased the ambient radio noise floor. Please don’t use the maximum power unless it is absolutely necessary.

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