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Mr.RC-Cam

FPV Hat Project

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I posted about my FPV Hat project a few weeks ago. Since then I've been asked how it was going. So here is an update.

My design goals are simple: Build a decent performing wearable monitor that others can easily duplicate for under $125. Ideally it would provide better resolution and perhaps have more comfort than current FPV goggles.

I thought I would share what I had in mind in case full disclosure helps with my search for a suitable 800x600 display. That said, here are some photos of a prototype using a cheap LCD monitor. I will admit the monitor does not satisfy my quest for hi-res, so hopefully a good candidate will be found one day.

First Photo:

The special FPV Hat has a strange looking long duckbill to accommodate the monitor's placement. A drop-down lens (under duckbill, not shown) allows the user to focus the image. Of course the stock hat needs some mods to help block out the light, but that part is not rocket science. Also shown is the Chinese Monitor (intended to be a automobile rear view mirror accessory).

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Second Photo:

I gutted the LCD and was excited to find that it is a one-piece module with dimensions that are perfect for the hat's built-in pocket. With the case removed it is lightweight too, so the hat will be easy to balance on the user's head. At this point I was thinking that I had a winning combination.

LCD's dimensions: 3.0 x 2.3 x 0.4 inches

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Third Photo:

I removed the stock cable and soldered on my custom wiring (shielded 3-wire audio cord with RFI Toroid). Simple stuff so far.

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Fourth Photo:

The monitor slides into a front pocket. The cable is routed out towards the back of the neck. At this point things were going too well. Nothing is this easy.

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Fifth Photo:

Inside view, the LCD monitor is shown in position. The drop down lens can be seen here too.

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post-2-126895248751_thumb.jpg

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At this point I did some outdoor tests and learned that the Chinese monitor was just not worth using due to its lower than expected resolution (their specs were exaggerations of their imagination). So, now it's just a waiting game until I find the perfect 800x600 TFT or OLED to install in the hat. :)

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That sux about the monitor but the idea seems really great. Thank you for sharing the project under developement. In the aerial film world, we have the monitors but the price would make you sick. I keep hoping that with the $6K HD monitors that we have gone to, that the prices of the lower res stuff would fall but that just hasn't happened yet.

Has anyone considered a football helmet since it has a solid mounting point (protective cage) and can easily be made with a veil. It would/could look cool too with the right paint job. Some helmets have comms too.

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Has anyone considered a football helmet since it has a solid mounting point (protective cage) and can easily be made with a veil.

I've seen motorcycle and welding helmets used, so a football helmet is not out of the question.

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How about one of those Pico projectors? The image could be projected on a small screen on the inside of the hat. Can't take credit for this idea (kist2001).

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A projector sounds cool (kist2001 mentioned it to me too). Just waiting to hear how it worked out for him.

For now, the FPV hat is put aside and I'm working on the ultimate grand daddy Trimersion FPV goggles hack. smile.gif

Edit March-2014: Here's the Trimersion hack from July 2010. I got my money's worth since I still use these goggles today.

http://www.rcgroups.com/forums/showpost.php?p=15699283&postcount=1740

Edited by Mr.RC-Cam
Added link to Trimersion project

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I am currently looking for a cheap pico projector. The second wave of devices has arrived pushing the first wave into the bargain bin. Once I find a sale on a unit with decent light output I will try this.

In the meantime I am working on my own Trimersion hack with a 5.8 receiver. :D

-Ken

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Here it is 4 years later and I still think about this DiY goggle-hat project. I was especially excited to see this cool goggle housing kit earlier this week: http://napolskimniebie.pl/_oferta/oferta.htm#rwd13

But the mechanical housing (hat, helmet, cardboard box, paper bag, etc.) is not the problem. That's because the monitor issue I ran into back in 2010 has not changed. The affordable (Chinese) 3.5" to 4.3" TFT displays are still claiming useless resolution specifications. That is to say, their advertised 640x480 and 800x600 resolution specs are the display format, not the actual visual resolution. So in practice, your eyes only get to see ugly 320x240 image quality (or worse). That marginal resolution is just not my cup of tea.

I spent several hours yesterday re-reviewing the small TFT's sold at the various online shops, including an endless variety of eBay choices. None have believable / trustworthy specs. So how about a shout-out: Does anyone have a source for a REAL 800x600 (or 640x480) 3.5" or 4.3" TFT composite monitor that does not blue screen? My budget for the TFT is about $100 max, but less would be nice. That's all I need to bring this project to a close and some joy to my eyes.

I'm not going to stop looking until this project is done. If / when the miracle occurs I'll come back with an epilogue.

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I've come to the conclusion that I won't satisfy my resolution goals if I use a TFT display module that has a native 4:3 aspect ratio. Given what I've found, the small 3.5" to 4.3" size 4:3 displays are older technologies with lower pixel densities than I want.

There's some affordable 5" 16:9 displays that use newer TFT technology. The pixel density is slightly higher on some of them, so I think I'll concentrate on trying one out. The side affect of using the 16:9 size screen is that the display needs to be setup to rescale the FPV image to 4:3. The net result is that a 5" display's active video area will end up being about the same physical size as a 3.5" 4:3 display. So the module's larger size and weight goes to waste, but that's not a deal killer for me.

I'll order a 5" TFT module. If the image is indeed better looking than the 3.5" TFT's I've tried, then next on the list is to find one that avoids the blue screen issue.

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If only a decent grade LCD screen were available!

Yes, that is the biggest challenge. I'll admit that it isn't hard to build your own goggles that have slightly better image quality than most of the commercially made goggles (and at a fraction of the cost). But my goal is something that has a radically better video image.

There's a lot of confusion amongst the DiY goggle builders regarding monitor resolution; Those cheap displays are advertised using the display's interface format (i.e., 640x480, 800x600) to represent the resolution. Those numbers sound great, but they are useless on their own. The missing spec we need is anything that helps us know the physical pixel density. The usual 3.5" 4:3 monitors are rarely more than 230K total pixels. Just to offer an extreme comparison, I think the newest iPhone 5S' little screen has 1.5M pixels. I don't need that many. :)

I received my 5" monitor and prototyped the ghetto goggles out of cardboard and $5 Fresnel lens. Since the new TFT is 16:9 format display it is effectively a 3.5" monitor when configured for 4:3 format. The visual resolution is acceptable (better than the small eBay monitors I've tested). But it's not the monitor to solve my hunger for something that blows me away. The hunt continues.

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I'm not going to stop looking until this project is done. If / when the miracle occurs I'll come back with an epilogue.

Epilogue:

I finally have FPV goggles with the video image I've been wanting for many years. Details are here:

http://www.rc-cam.com/forum/index.php?/topic/4026-mrrc-cams-diy-3d-printed-fpv-goggles/

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