FPV visor discussion

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FPV visor discussion

Postby Rixx » Fri Oct 14, 2011 7:14 am

Hi all. I decided to go for next step in RC flying, FPV. For starter, I try to keep it low cost, but reliable. I got 5.8GHz bevrc video link, built helical & cloverleaf antennas, I have frsky telemetry system. But the catch is video display. Spending $300+ on googles is no way for me, and those cheap ones from hobbyking seem inferior to me - low res + blue screen of death. I'm checking RCMR web and youtube daily in hope of some fpv visor info :D.

I got pretty nice 3.5" 640x480 lcd from ebay, for about $17. After some testing by covering RX antenna with my hand to induce interference, I was surprised that LCD didn't turn off until whole picture went static with no recognizable image. It would turn right back on under a second, If I removed my hand from antenna. The only problem was it needs pretty clean signal to lock on sync and switch back on (Before you ask :P, yes I tried putting OSD between video RX and LCD - cheap one from hobbyking. The one thats in series with video line. Didn't work, OSD was barely visible on lcd and did't help in any way. If video signal was lost, OSD started blinking its red LED. Maybe paralell one would generate sync?). So I guess if I loose video at the distance, I'm done :D. But I think my CPL antenna setup will be more than enough for non-long range flights, under 10km.

After that tests, I bought some grandma reading glasses :geek: :D . Highest dioptre I could get was +4. Those allow me to get my nose 10cm from the LCD, but that is not enough. It would not fit inside any welding visor I tried at local shop :roll: . I'm thinking of some fresnel lens in front of lcd, but I'm afraid that it displays correctly only around ceter and distorts at the edges.

Another point - if I flip front visor cover with attached LCD up, I still have grandma reading glasses on my nose. And I can't see a thing with them on plus I get dizzy immediately :mrgreen:

I wonder if we could brainstorm some ideas while Bruce is busy.

Richard
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Re: FPV visor discussion

Postby Sid Sideslip » Fri Oct 14, 2011 7:36 pm

Using the mask idea, although it's possible to make up an eyepiece set that would focus on the lcd, at that distance the screen really is too close, which makes getting a distortion free image difficult, especially just using granny glasses.

It may prove easier to mount a hinged mirror in front of the filter window and mount the video screen outside, horizontally at the top of the welding visor. The lcd and mirror would be in a light proof box. The mirror would tilt to allow either vision of the lcd via the mirror, or straight through to see outside. The filter window really needs to be bigger to see out properly, btw; I'd cut it larger and make up a new frame and hinged mirror etc.

The mirror mechanism could also raise the eyepieces/glasses, so that you would see clearly outside.

An alternative would be simply to mount the lcd further out on a small box extension and hinge the lcd to raise up and allow you to see out...again, the window should probably be enlarged.

For stereoscopic 3D (which I want to try with two 5.8GHz systems on different channels using two cameras and Tx's on the plane) you could mount two screens on either side facing forward and have two hinged mirrors as shown in the ascii drawing below (the two o's represent eyes, as seen from above).


I \ / I
.o.o.

Note, you need a mirror set-up with 3D, as with two screens you need the extra room to allow for inter eye distance to be variable and for the two screens to "fit" between your eyes.
What goes up...better bloody stay up (until I say otherwise).
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Re: FPV visor discussion

Postby Rixx » Fri Oct 14, 2011 9:02 pm

3D setup sounds really interesting, would love to try it. For my mono-fpv I though about extension box to mount LCD further out than welding mask would allow inside, but I'll have to buy the mask and try in practice, if it won't be too noseheavy :D. I'm not sure how would mirror setup work. Wouldnt be the image flipped somehow? What about osd text then? :)
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Re: FPV visor discussion

Postby rogueqd » Sat Oct 15, 2011 9:33 am

Do you really need the welding mask? What about making a little viewing box, with the lcd's at the back and the glasses just inside the viewing slit? Just like the viewing boxes you see on youtube, but the granny glasses let you make a much smaller box. Unless you want a head tracker of course.
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Re: FPV visor discussion

Postby Rixx » Sat Oct 15, 2011 12:37 pm

Well, I don't know other way how to attach lcd and glasses to my head, and keep it lightproof. I do not have any stand to put box on, and welding helmet/mask provides convenient way to mount other harware on, and I can walk and turn around freely to aim head-mounted directional antenna towards plane while flying close. I will probably build simple box anyway to fly, while speculating about visor :D.
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Re: FPV visor discussion

Postby rogueqd » Sun Oct 16, 2011 11:27 pm

Rixx wrote:I can walk and turn around freely to aim head-mounted directional antenna towards plane while flying close.

Have you actually thought that through? Walking around blindfolded, probably. Pointing an antenna while blindfolded, maybe, with your head, doubtful. All of the above while 'blindfolded' and flying a plane FPV? You're asking for a crash and a bruised knee/elbow at the same time.
Personally I'm not even going to try standing up while flying FPV. At least not until I'm used to it sitting down.
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Re: FPV visor discussion

Postby Rixx » Mon Oct 17, 2011 6:40 am

rogueqd wrote:You're asking for a crash and a bruised knee/elbow at the same time.


You`re right :D. That aiming thing surely needs some more thinking :lol: . But still I'd prefer something attached to my head, than to anything else. Keeping head stuck to a box would surely hurt my back and neck.
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Re: FPV visor discussion

Postby rogueqd » Mon Oct 17, 2011 9:00 pm

Rixx wrote:Keeping head stuck to a box would surely hurt my back and neck.

yeah, I'm not sure there's really a good answer to that. Get some smaller LCD's so they fit closer to the visor? I settled for buying some Fatshark goggles, out of size/money I decided to go for size and sacrifice money.
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Re: FPV visor discussion

Postby Rixx » Tue Oct 18, 2011 7:32 am

It's not LCD size, but minimal focusing distance, whats causing the problem. I got another idea for visor - square tube with reading glasses and LCD, attached to ski googles. That would let reading glasses close to eyes, and tube hinged on the top could remove them if flipped upwards.
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Re: FPV visor discussion

Postby Rixx » Thu Oct 20, 2011 6:29 am

So I started building. I found long cardboard box with just right dimensions, painted black inside, velcroed LCD... I couldn't find reasonably priced skiing googles, so I started sanding custom face mask from XPS foam. It seems to be working so far, but it looks really weird :lol: . I'll upload some pics after more progress.
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