I know I'm not the first one to come up with the idea of a homemade digital picture frame. I'm not even the one to come up with the idea of using the particular lcd screen and digital photo viewer that I chose. But I can write a darn good how-to about it, and there's no stopping me!
(3/14/07) Edit: For an easier setup, take a look at my new picture frame here.
Step 1: The basics
The SanDisk Digital Photo Viewer is basically a little black box with 4 slots on the front to accept different types of memory cards from digital cameras. You stick in the memory card, hook up the composite video(or s-video) to the tv, and turn it on. The device automatically plays a slideshow of your pictures, and you don't have to do a thing. This makes it really really useful for this project.
The particular screen I used was a 5" Zenith lcd screen made to attach to the GameCube for people who enjoy playing high graphics videogames on small screens : ) The internals are identical to the Sony PSOne screen or the Zenith Xbox or Zenith PlayStation 2 screens of the same size. If you see any of these on eBay for less than $40, grab 'em!! Considering that suggested retail value is over $100, that's a bargain. I've seen used ones for as low as $25(+S&H). Granted there are other screens that you can use, and by all means go for it. The basic concept is that in order to keep things simple, the screen needs to be large enough to enjoy viewing pictures on and already accepts composite video. It's that easy.
Step 2: The frame
Step 3: The guts
The connections are simple. Even if you have minor experience with soldering it's easy. All you have to do is connect the video out from the viewer to video in on the screen (see picture), connect power to the screen and viewer, and make sure to connect the ground of the screen and viewer together. That's it.
Once again, sheer dumb luck came in handy. Now, the screen can only take 7.5 volts of power. Much more than that, and it'll fry. The adapter that comes with the viewer is labeled for 12 volts (but I was measuring 15 with my multimeter... all lies!) and so you'd think that the viewer needs 12 volts to run. Not so! I just so happened to test if it would run off of 7.5 volts, and luckily it does. This means that you only need one adapter to power the whole project, and you don't need a voltage regulator or whatever to step down the power for the screen. If you got a Sony PSOne screen, hopefully it'll come with a 7.5 volt adapter. My GameCube screen only came with a car adapter, so I just salvaged a Sony PSOne screen adapter I already had. However, for those of you who aren't in the habit of hacking up lcd screens to use for making portable Super Nintendos and such, I think you can get a 7.2 V adapter at RadioShack or somewhere like that for not too much. Should work...
Edit: Due to problems people have had, I'll just state it here and now - make sure that your power adapter is not giving you more than 9 volts! Check it with a multimeter yourself! If you're getting an image, but it's got something weird going on with your picture, then your voltage is probably incorrect. Easy way to test your setup without having to build any sort of regulating circuit would be to connect 5 or 6 AA batteries or a 9 volt battery. Naturally, they won't last long powering your setup, but it's an easy way to check if you're doing everything right.
Double Edit: Also, make sure your power adapter is providing enough current to power the system. I don't recall exactly how much this system draws, but if you can get something that provides at least 800 mA or higher then you should be good (I'd say go for 1 Amp to be safe).
If you find that you have an adapter that's just unreliable in its voltage, then go find a "7808 voltage regulator". Google search for how to use a 7808 voltage regulator, and then USE IT! It will then give you a steady 8 volts - just right for this project. RadioShack sells a linear regulator than you can adjust the output voltage, but you have to build a small circuit to get the output you want.
Step 4: Mounting and housing the screen
For me, mounting items in my projects = copious amounts of hot glue (and epoxy where needed). I attached the screen to my custom matting with hot glue, I attached the metal frame to the matting with hot glue, I attached the digital photo viewer to the back of the screen with hot glue, and I attached the power switch, relocated remote sensor, and power input jack to the backing with hot glue. Lots of it.
The backing was made using some high-impact plexiglass that I bought from Lowe's. I sized it and cut it with a dremel, although something like a table saw probably would have given a better cut. However, I don't have that and I was basically making this whole design up as a I went along.
I then spray painted the underside of the plastic with some white Krylon Fusion spray paint specially made for painting plastics. If you've never used this stuff before, it's awesome. No priming, and it holds great. Dries fast, too - fifteen minutes! And you only have to wait 30 seconds between coats! Good stuff and worth the money. You can get it at Wal-Mart, I think. The reason I painted the underside of the plastic was to give it that cool iPod look. If you've ever held one before, you know what I'm talking about - colored on bottom with a shiny plastic coating over it. It's a neat effect and easy to do. My pictures don't really convey this effect, but it's pretty cool to see in person.
Step 5: Attach the backing to the frame
Edit: Ah well, I guess it was TOO strong - the tab that went in between the rollers pulled off of the plexiglass part, leaving a couple of spots with no more paint. My new suggestion is to just use some strong magnets, or maybe some sort of hinge and lock mechanism. Go visit a hardware store and see what you can find. I personally used some Rare Earth magnets as the new way to attach it. They work great!
Step 6: Putting it all together...
One cool thing about all this is that the aluminum is wide enough to hold the frame up at a good angle, thus eliminating the need to attach the prop that was originally on the frame.