I'm working on a project where we are attempting to transmit a warning on 5.8GHz when a drone enters a restricted airspace, and figured there has to be  an easy way to implement MinimOSD or similar. The current through it to just hook up a camera with the lens cap on, and overlay a warning message such as "WARNING - RESTRICTED AREA" that would flash momentarily.

I'd like to try and change the "no data" so that I don't need to fake some telemetry to get it to work, but am utterly lost as to where to find that or how to do it.

Thoughts.... Suggestions... Offers to make the change for a fee?

Thanks

Chris

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sounds like you think you can just inject an overlay to another analog video transmission.

the "project" is a waste of time, for several reasons, but essentially because you do not understand how such transmissions are made and what it takes to do something like that.

sorry for shooting down you ambition, just trying to save you some time.

Thanks for the response Andre, but how is this different than what MinimOSD is already doing for me? I can already change the characters and adapt the outputs from the telemetry data, vehicle info, etc, I'm just looking to use a static version rather than needing the data feed... Essentially changing the characters from saying "NO DATA" to "RESTRICTED ZONE".

Not saying you are wrong, just not seeing how it is so dramatically different.

Thanks

Chris
 
Andre K. said:

sounds like you think you can just inject an overlay to another analog video transmission.

the "project" is a waste of time, for several reasons, but essentially because you do not understand how such transmissions are made and what it takes to do something like that.

sorry for shooting down you ambition, just trying to save you some time.

It's one thing to properly time things to a video stream , when a dedicated chip perfectly understands sync (when scanlines change)  and output some data.

It's something completely different to hit some modulated data at a (unknown to you) distance, just the varying time your "modification" based on your perceived timing (where you are) would need correction to a signal recieved somewhere else. with a very different latency between the UAV and user, and YOU and that user.  (and - you do not know where the user is.)

Mostly - your injectied signal would also need straight line of view to wherever rx is.

And that's before I mention signal polarization, strength, etc, etc.

Andre, I think we are talking past eachother...

I'm planning to use a camera, and the minimOSD setup, just modify the characters to change the message.

Chris

Are you just saying that you want the OSD to show "WARNING - RESTRICTED AREA" when a Mission Planner Geo-Fence Event is triggered and hide the rest of the data until you exit the restricted area?

i understand that you are try to modify/inject OSD text/picture into someone else analog video link - correct ? 

Alright, I think I've just had an "AH HA!" moment and figured out what you're trying to do.

Is the idea to setup a MinimOSD (with or without a camera, video feed doesn't matter) connected to a 5.8GHz Video TX that just outputs a black screen with the words "WARNING - RESTRICTED AREA" on the display? You absolutely can set this up, and pretty easily with some very minor modifications to the MinimOSD source code.

I like the concept, however, I don't think this in any way accomplishes the goal of notifying a pilot they've entered a restricted area:

 - The receiver of the video feed is the pilot's goggles or screen, not the drone, so there's no way to only display this on the pilot's screen when the drone itself enters the area, it could work if the pilot is standing within the restricted area but....

 - There's also no way to really accurately control the area the signal covers. You can play with different antenna types and power levels to try to "shape" the coverage area, but it's just a radio signal that will travel out infinitely until it's too small to be detected.

 - You'd have to cover all the 5.8GHz frequency bands. Current analog video transmissions run on specific channels within the 5.8GHz band and the pilot's VTX and receiver are tuned to one of these frequencies. Your transmitter would either have to constantly jump from frequency to frequency so that a pilot on any of the channels would see it, or broadcast in such a way that it just blankets everything used for normal RC Analog Video. And in almost all cases they would just see static on their feed rather than a clear warning message. Not to mention this doesn't even begin to cover digital video transmissions like DJI's LightBridge.

And these are just a few of the many obstacles to this solution, assuming I've correctly understood what you're trying to do. If the goal is actually to inject characters into someone else's video stream, Andre K is absolutely correct, you would need some NSA-level funding to figure that one out!!!

I think the correct option, although I don't know the process, is to get your region of interest added to the No Fly Zone maps used by companies like DJI and 3DR (Mission Planner). The flight control software will automatically notify the pilot they've entered a restricted area and in some cases will prevent them from entering that airspace.

No, all we are trying to do is show the words "WARNING - RESTRICTED AIRSPACE" on our own video feed, through our MinimOSD unit, and down to our video receiver, as a static default message on the minimOSD when no data is received from the Pixhawk. 

Thanks John, that is exactly what we are attempting to do... When you say simple, can you explain where an how to do it? It is mostly a proof of concept. This xmit platform will most likely be flown on a vehicle following the target uav, transmitting on their video frequency monitoring is being done on the ground prior to launch) at 2+ Watts on a toggle switch, so the threat user sees it intermittently. If it doesn't entirely work, that is fine, as it is a proof of concept / demonstration. 

Before you RF Nazis lose your minds, this is being done with full permission of the FCC on a government test range with all approvals already coordinated.

 

your two recent posts are completely contradicting - i guess there is more BS around, like the FCC-ok  :)

cxgiacomo said:

 on our own video feed, through our MinimOSD unit, and down to our video receiver

AND:

 This xmit platform will most likely be flown on a vehicle following the target uav, transmitting on their video frequency monitoring is being done on the ground 

So you should ask "RF Nazis" how well this FCC approved test will work, because it would be an embarrassingly clueless application if it described the idea like here.  (I will not comment more on this topic, have fun.) 

Sorry if I offended you somehow Andre, that was certainly not my intent.  I am not presuming that the test will work effectively, I'm just asking a simple question about how to change the overlay to display a message as a proof of concept. The FCC question was merely to address what most people would be immediately concerned with when we mention transmitting at normally illegal power levels.

Again, I'm sorry if I upset you somehow, it was never my intention to argue with you or disrespect you in any way.

Chris 

you did not upset/offend at all. I just got tired of trying of fooling around trying to understand what you really try to do.

I just wish you tried in small scale, (on ground, with attenuated/sane transmission power) first, many 5.8Ghz channels actually overlap each other, and you will never succeed injecting video this way in a reliable fashion.   At worst, this method may jam an inexperienced pilot or one whithout RTL  - and cause injury/damage.

Anyway - making minimOSD output that text is no problem at all, it's open source, I did program on it a lot due to some payload  use.     get Minimosd-Extra source, and any freelancer will be able to make it do that.  

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