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Old Aug 17, 2013, 01:59 PM
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Linwood NJ USA
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Mobius action cam and gps problem

Heres my problem. I have the möbius cam ( great ill camera) its affecting my Naza gps. As soon as I powere the camera on it starts degrading my gps and I start loseing sattelites. If i shut off i get full sattilite lock This is not a fpv quad. Just stock dji f450 with the naza gps I'm using the internal camera battery. I have the camera and gps separated as far as I can get them. The gps sits up on the back of the quad about foe inches in a copper foil puck. The camera is mounted in the möbius swivel mount that hangs down underneath.
I really don't want to wrap the camera in copper tape as I will be using for other things. Someone mentioned spraying the inside with rf shielding.
Would this short anything out?
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Old Aug 17, 2013, 08:45 PM
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You would need to open it and make sure nothing on the circuit board contacts the inside of the case. If no contact (except screw holes) then it should be fine.

This is the page of chemicals, you should be able to buy them from Mouser, Digikey, or Newark (USA Farnell), or a few other places.
http://www.mgchemicals.com/products/...rfi-shielding/

I would go for the 841, 842, or 843 product. The graphite should do a better job at higher frequencies, but I think it needs to be pretty thick for this to work. Pretty much every thing else was already covered by VideoKing in the other thread.

I haven't opened my camera yet to see what kind of issues you might run into, so I can't really help beyond what I've said to far. Just remember that paint takes up space too, so things like the sensor mount may not fit if you paint it, again it would be up to how much slop is made into the plastic.
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Old Aug 17, 2013, 09:00 PM
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To add, it isn't cheap! And this is only the nickel stuff which is cheaper than copper or silver.
http://www.alliedelec.com/search/pro...FY8DOgodrHMAdQ

I would probably try the chrome model paint inside and see how well it does or doesn't work, that way you would only be out a couple bucks.
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Old Aug 18, 2013, 04:54 AM
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Just to add to the points made above.

You only need a THIN coat of this stuff for it to work. Making it thicker has zero effect on its RF shielding effects.

All these graphite spray's work on the micro strip line effect, by which you are effectively creating millions of short conductive paths which form a mesh Faraday cage over the item you are coating.

Read the data sheets and they will tell you the optimum thickness of coat for the frequency you're trying to kill. (in your case GPS which is 1.5Ghz)

Also remember to make sure there is a contact, surface to surface, for both side of the case (when they are fitted back together), as this will improve the shielding quality massively.

PS the chrome paint wont work as the color, (if metal flake), is suspended in the paint which insulates the metal flakes from each other.
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Old Aug 18, 2013, 08:57 AM
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Linwood NJ USA
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That stuff is way too expensive I may try lining the inside with foil tape.
The reason I post here , is they don't think this is important issue for a AP camera.
I really don't know what you can post there without getting crap.
Isn't that the support thread. ? I could care less about techno babble.
What if this interference caused a crash or interferes with something else. You think the developer would coat the inside of these . It's one thing to hawk this camera on a AP forum then not to do anything to resolve this problem.
Sorry for the rant.
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Old Aug 18, 2013, 11:03 AM
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I bought this , I'll let you k ow if it works.
838 Total Ground Carbon Conductive Coating
http://www.amazon.com/gp/aw/d/B008OA931A
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Old Aug 18, 2013, 12:13 PM
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Quote:
Originally Posted by mori55 View Post
I bought this , I'll let you k ow if it works.
838 Total Ground Carbon Conductive Coating
http://www.amazon.com/gp/aw/d/B008OA931A
Now go and read the data sheet. Here
2 thou thick and no more......

And I add again for your info. Wear a mask and don't breath it in, it's dangerous stuff.
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Old Aug 18, 2013, 12:57 PM
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Originally Posted by mori55 View Post
That stuff is way too expensive I may try lining the inside with foil tape.
The reason I post here , is they don't think this is important issue for a AP camera.
I really don't know what you can post there without getting crap.
Isn't that the support thread. ? I could care less about techno babble.
What if this interference caused a crash or interferes with something else. You think the developer would coat the inside of these . It's one thing to hawk this camera on a AP forum then not to do anything to resolve this problem.
Sorry for the rant.
You bought a cheap, but remarkable camera. It's in a plastic case.
You are one of many thousands that bought/will buy this camera.
You experienced problems - many others don't. You expect the developer to fix your problem for you. That means the cost goes up to everyone - even though the majority haven't got a problem !
Eliminating RF interference or other electro-magnetic non-compatibilty issues can be very complicated and varies wildly from one type of installation to another.
Sorry, it's incumbent on you to go learn (steep learning curve) or rely on some kind soul giving you a series of answers that may/may not work on your installation.
This issue is way to complex to try and fix on the other forum and you may/may not get a solution on here.... depends if your lucks in or not.
The developer coating the inside of the case raises the cost. The case is a very snug fit to start with and.... it may not prove effective in a particular installation.

What about the guys that want to remove the case to save weight ?
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Old Aug 18, 2013, 03:21 PM
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I noticed in most forums topics ebb and flow. But I wanted people to know thT this could be a serious problem on rigs using gps. As more cameras are more are going to be I use on quads with gps. Problems will arise and who knows what may happen?
I'm sure the the developer will do nothing about and it will be up to us to figure it out.
But when I'm on the support thread and it goes on and on about a lens that doesn't exist it makes me wonder whats the big deal about bringing this subject up.
I realize you can't tie up the whole thread about it
The reality is if people aren't interested in it will die out anyway.
Show we just post what your interested in?
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Old Aug 18, 2013, 04:31 PM
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Look, one person asked a question, a couple others said they saw the same thing, an answer has been given, hopefully it works.

Technically, all electronic devices sold in the USA need to be certified to meet the FCC emissions standards for their class. Since this is sold direct from China, it kind of goes under their radar slipping through. From the interference report it sounds like some (or all) of these cameras may not pass so it might be in the best interest of the manufacturer to spend the extra $.50 each unit to shield the inside of the case, and charge us an extra dollar for the trouble. Clean devices may continue to slip past the FCC, dirty devices will eventually get unwanted attention. This problem may not have been discovered in prototype because the prototypes had machined aluminum cases.
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Old Aug 18, 2013, 09:42 PM
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Quote:
Originally Posted by village_idiot View Post
...
From the interference report it sounds like some (or all) of these cameras may not pass so it might be in the best interest of the manufacturer to spend the extra $.50 each unit to shield the inside of the case, and charge us an extra dollar for the trouble. Clean devices may continue to slip past the FCC, dirty devices will eventually get unwanted attention. This problem may not have been discovered in prototype because the prototypes had machined aluminum cases.
You are jumping to many conclusions! First of all the Mobius prototypes also had a plastic case, just like the released one, only it was colored gray! The heat sink was machined aluminum, replaced by a thinner stamped aluminum one, but that is immaterial. You jump to a conclusion that the Mobius has bypassed some standard for emissions, because SOME GPS units have interference, but MANY do not according to other users. How do you explain that? Did it ever occur to anyone that the GPS device is a receiver, and some may not have sufficient RF interference filtering, just like some RC radio receivers can be influenced by RF emissions from some switching voltage regulators used in some speed controllers and some UBECS if they are located close to the RX. I don't see modelers clamoring to tell the switching regulator manufacturers they don't meet FCC standards and to clean up their act. Geeze! If you've proof of all these allegations about FCC non-conformance, produce it, but if not, maybe just find out more about why some GPS devices are fine along side the Mobius and others are not. Clearly it's not just the Mobius contributing to the issue, and I don't want to pay an extra dollar with more weight to maybe solve a problem with your specific brand of GPS.
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Old Aug 18, 2013, 09:56 PM
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Quote:
Originally Posted by mori55 View Post
...
But when I'm on the support thread and it goes on and on about a lens that doesn't exist it makes me wonder whats the big deal about bringing this subject up.
I realize you can't tie up the whole thread about it
The reality is if people aren't interested in it will die out anyway.
Show we just post what your interested in?
The ONLY reason there was continued chatter about a lens that "doesn't exist" (in fact it does exist), is because users wanted it for their camera, and kept asking about it, even though I repeatedly replied when there is anything new to report, I would post about it. They kept asking, over, and over, and over. You got tired of it apparently, but at least it was something directly applicable to the camera, not to some other device like a GPS receiver, many of which work just fine sitting near the Mobius.

Off topic posts lead to more off topic posts, and so on and so on. In a very short period of time, the thread becomes meaningless. In fact, this discussion seems to be doing it to this thread, so I'm signing off...
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Old Aug 18, 2013, 11:42 PM
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Then those people having problems must have a broken camera and should see about an exchange since all the cameras must normally have more controlled emissions since only a few people are seeing this issue. I certainly have not seen any issues with any of my radio equipment, but I'm not using GPS either, maybe I'll fire mine up next to the GPS network time source at work tomorrow and see if the signal strength reported changes.

BTW, the extra shielding goes both ways with helping to keep other emissions out of the camera which could cause noise in the video or audio. It's a good thing either way. And let's not forget that the designer is trying to break out of the cheap keychain camera area into an action camera area. So lets not bring cheapo ubecs and ESCs into this. If the designer wants to keeps improving the product, here is one other way that he/they might want to consider. If not then that's fine too and people who have a problem will need to solve it on their own or find another camera to use. But those having problems will constantly suggest going in a different way (different camera), except in the threads that are without question not open to differing opinions on the product. You seem to take all this criticism very personally. This camera is like an Apple product, those that may not "believe" without question are shunned as haters.

This camera is certainly without equal and that's without considering the price so don't even suggest that I'm not happy with the product. What I want is this product to continue to exist and improve, shielding inside is an improvement. Sorry I made the mistake about the case, I had thought that the earlier prototypes where made of aluminum because it is easy to create.
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Old Aug 19, 2013, 05:16 AM
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I think the point being missed by a lot of the "GPS complainers", (and I mean that kindly so don't take offense), is that this is a problem to those who are suffering, but of no concern to those who don't.
Hence open a thread about it to attract like minded users with the problem, (like you have already done)...

Because this kind of EMC/EMI problem interests me, over the weekend I have taken out every HD mini cam I have, (and I have quite a few), and also full size camcorders, a total of 12 different makes of HD cameras that can generate full HD video and exposed them to a number of GPS devices, (6 different manufactures).

Now I would love to say that you are completely right about the Mobius, and that it was the only model to cause problems. However it was not. I have a Contour HD and a Fuji compact camera, both of which could wipe out 4 of the 6 GPS unit when place immediately adjacent to each other.

I had 3 GPS units which were badly effected and 3 which showed only slight signal derogation when placed next to the Mobius.

There were other combinations that showed slight and serious problems when placed next to each other, so I can tell you with some certainty that the Mobius is not the only culprit when it comes to generating problems.

Ironically I use a Mobius as a car dash cam and it sits about two inches to one side of my TomTom and I have NO problems at all, and I have reduced satellite signals due to a tinted windscreen in the car. So go figure...

You need to remember that this is a problem that ONLY occurs for people trying to cram a whole load of electronics in a small area like a model. The VAST majority of people buying this camera probably have never heard of aerial photography, so to claim that the manufacture needs to sort out this problem is nonsense. The camera is sold as an Action Cam and nothing else. If you decided to use it for something else like aerial video's then so be it.

I'm sure in time if the manufacture realizes he is loosing sales to the AP community due to problems he might well offer a "shielded model" but that up to him, and no doubt it will cost more.
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Old Aug 19, 2013, 06:53 AM
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OK done some more testing and also done an RF sweep from 1.0Ghz to 1.6Ghz to check out the problem.

As you can see it's basically just random processor noise, the type seen on anything these days that contains micro controllers or high speed video data processing. You should note that although it looks dramatic, we are looking as very low levels of RF here. Down in the micro-volt/meter level.

The interesting thing I found was that the the heat sink on top of the DSP chip seems to be acting as an antenna for most of the RF noise. When I ran the Mobius open without the heat sink for a few moments the noise level was dramatically down.

My next move is to make a ultra thin copper screening plate with which to cover the chip and I will ground it out as well, this should form a screen between the chip and the heat sink.

Now I have baseline readings to work from I will be able to tell you if it does anything useful.

I will report back with results when done. (maybe some time.)...
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