Color LCD Viewfinder with an NTSC analog composite input

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Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 2:43 pm

I have an LCD view finder from an old JVC VHS-C camcorder. The main chip is the SONY CXA1854AR, implemented with composite input. The LCD panel works perfectly. I'm still working on the backlight. Has anyone ever messed with one of these LCD viewfinders? Any good suggestions for an application? Helmet mounted display/night sight come to mind.

This has been the result of much continuity probing and datasheet studying.

I will try to get an action shot up as soon as i can rig a useful backlight.


Edit:
CXA1854AR LCD decoder/driver
http://www.alldatasheet.com/datasheet-p ... 854AR.html
Attachments
IMG_0342-640.jpg
Backlight board
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IMG_0339-640.jpg
The other end
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IMG_0338-640.jpg
The whole thing
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Last edited by f00barbob on January 31st, 2011, 2:47 pm, edited 1 time in total.
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 2:45 pm

More pictures...
Attachments
board-bottom-640.jpg
Main pcb detail (bottom)
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board-top-640.jpg
Main pcb detail
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IMG_0344-640.jpg
Backlight board and LCD
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 3:10 pm

Action shots.

Backlight temporarily constructed from a mini maglite, a plastic bottle cap, a piece of paper, scotch tape, and foil tape.
Attachments
rig.jpg
Maglite+bottle cap = backlight?
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zelda2.jpg
waaah no controller
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zelda1.jpg
Ocarina of time...
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby nes » January 31st, 2011, 5:46 pm

Great work bob. I can't think of a use for it right away, but anything you naturally hold up to your eye could be augmented with it I guess. Binoculars with an info display in one eye perhaps?

I hacked a 3" camcorder LCD which also has a Sony chip. I found I had to poke some registers over a serial bus to set the contrast, tint, etc. before I could see anything. Was it the same for this one?
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 5:59 pm

Other than tracing power lines, i haven't really done much... It's all ready to go with not much more effort than a CRT viewfinder. This chip supports color adjustment by the assorted potentiometers on the board. Still can't figure out where the analog signal comes in the connector (i've been feeding it straight to the input pin), but I've been working on the backlight. I'll probably just use the original one as a diffuser for an led backlight... I believe the chip is what actually handled the overlay for record and the battery indicator. I'm hoping I can interface that to a microcontroller for overlays.
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby nes » January 31st, 2011, 6:21 pm

Just found a picture of the one I did

Image

The connector at the bottom goes to my PC parallel port which runs a simple program to poke the registers. I think the registers were in a separate DAC chip which was just generating control voltages for the Sony part. (I did this a while ago so I don't really remember the detail.) I guess they just replaced the control pots with push button controls for this camera.
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 8:48 pm

That's pretty slick. I know if I had to face anything like that, I'd have probably given up.

Just finished cramming it all back in the case... It draws 100mA @ 5v and 32.5mA @ 12v for a combined .89 watts...
Attachments
IMG_0363.JPG
The guts...
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IMG_0359.JPG
Diffuser installed
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IMG_0357.JPG
Bottle cap diffuser
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby f00barbob » January 31st, 2011, 8:52 pm

So far, it hasn't given me the slightest bit of trouble...
Attachments
IMG_0369.JPG
more action shots...
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IMG_0366.JPG
MORE
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IMG_0365.JPG
more
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby MS3FGX » January 31st, 2011, 10:04 pm

Very clever diffuser, image looks great with the LED backlighting too.
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Re: Color LCD Viewfinder with an NTSC analog composite input

Postby arfink » February 2nd, 2011, 12:50 pm

I'm thinking HUD, or possibly as the element for a really little homemade projector. Looks great BTW.

BTW, what model of camcorder is this? Is JVC VHS-C the specific model number, or the series? I'm interested in getting one now to play with, since alot of camcorder LCDs are not composite input, but instead are just driven digitally, making them much more difficult to hack.
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