www.mouser.com. Mouser has an absolutely amazing collection of parts, and they might be able to help.
Screen Mounts, continued
After thinking about lostreception's comments, I realized the mounts I'm making don't allow for any positioning flexibility, and I'm considering a change to allow adjustment of the tabs. This would be ideal if there is a way to leave the headunit in place and just move the faceplate. But that would mean two sets of tabs fastened at the same points -- the HU mount and the screen mount -- and then the position of the monitor would change slightly. Adjustability would also let me refine the position after drive testing, and would let me get a perfect fit after I finish the bezel.
I think I can devise a system where each side of the screen mount has one panel, and the tabs are on separate panels. Two fasteners with slots in both panels would lock them in place, and it would let me change both depth and angle of the tabs. Only a small amount of adjustment would be fine: maybe 1/4" horizontally and vertically. I just need to play with some designs to see what's required. I won't have to scrap what I've done, but there will be significant changes. It appears that by cutting off the tab portion of the existing bracket panels, and making new tab panels, I can get what I need.
The interesting part of this is that it would move me back closer to the Meccano approach I used in determining the screen's position.
Screen Mount Sides Finalized
I decided to pull in my horns a little on the positioning flexibility issue. Building in adjustability also means making parts over, and I want to move ahead, not sideways. This mount is made of relatively thin material, and I can do a little flexing on it if I have to. Once the screen is installed, I can add shims under the feet if necessary for alignment. The one thing I don't want is to flex the installed screen and find I cracked it.
I countersunk the holes for the screen mounting screws. Then I bent the tabs into their final position and drilled the holes for the locating pins they ride on. Those are the only holes I needed for a test fit. I'll drill the mounting holes, and they'll be done. Here are the almost-finished side brackets:
Click images to enlarge.
I assembled the brackets to the screen and took it to the car for a test fit. It fits great, just the way I wanted it, with no space conflicts. Oh, boy, am I gonna like this . . .
Edit: Whoops. Just realized I forgot to bend the strengthening flange on the bracket sides -- the edges facing each other in the picture. I can still do that in the bender, because there's just enough gap at the end of the bender to let the tab fit in there during the process. That's next, and then the bottom rail and the PCB mount.
Screen Support Rail
I realized that I don't want to task those tiny screen mounting screws with too big a job. I originally had them supporting the entire weight of the screen, but they aren't really intended to be structural components. So I built a bottom rail that will take the support role; now the mounting screws will just hold the screen in the brackets. This rail is the same 22-gauge steel as the rest of the bracket. I made the main bend in the sheet metal bender, then had to do the ends in the vise, making sure the overall width was exactly the 8-7/8" width of the screen. Here's that part, and then a picture of it assembled into the side brackets:
Click images to enlarge.
You can see that I did put the final bend in those brackets.
Now I'll make the PCB mount and get it all assembled for another test fit.
Screen Mount Final Assembly
I need a place to mount the screen's printed circuit board, and the PCB has to stay almost as close as it would be if it were still in its case, because the cables are pretty short. A simple panel attached to the brackets behind the screen works well because it provides a strong support for the brackets. This mount will sit a bit below the top of the bracket, because there are cables that connect at the top of the board, and they have to clear the bezel.
I cut a piece of the 22-gauge steel, 5"x9-5/8", filed the edges smooth and rounded the corners. Then I bent down the ends to give a final length of 8-7/8", exactly the same as the width of the screen. The resulting legs are approximately 3/8". I laid the PCB on it, used a spring-loaded centerpunch (less than $3 from Harbor Freight, and a really good addition to any shop) to mark the hole locations, and drilled 9/64" holes for the standoffs. I used serrated lock washers to make sure the standoffs stay in place.
I'd have sworn I took pictures, but I can't find them on the camera or the computer. I'm sorry to have to leave them out. I'll add some shots later when I disassemble for paint.
Next, I drilled matching 1/8" holes in the PCB mount, the screen support rail and the brackets, and tested their alignment with small nuts and bolts. Alignment was crucial, because I don't want to flex the screen. The screen slipped into place with the holes perfectly aligned. I did a vehicle fit check to make sure everything is what it should be. The alignment checked out, so I did the final assembly with pop rivets.
I was short two standoffs; they'll go in the open holes when I get them. Here's the assembly:
Click images to enlarge.
When I installed the screen and PCB, I noticed that the 1/4" standoffs for the PCB are so short that it's difficult to move cables around under the board. There's a cable from the screen that attaches to the back of the PCB, and it needs to run between the screen and the mount. I'll have to install the cable before I put the board on the mount.
Here's the assembly:
The small printed circuit board hanging down in back is the touchscreen board (I think). It was held inside the case with double-sided foam tape. I expect to use the same material, and I'll attach it to the back of the screen support rail. I'll drill a 9/16" hole in the driver's side bracket to pass the cable through.
Another fit check with the complete assembly in the vehicle shows everything lines up nice and square. Now I can exactly match the position of the screen mockup to this, and lock it down tight. I'll use that to build the bezel while the real screen stays safe.
There are a couple of last jobs on this:
(1) Strip everything off it and drill the hole to run the small touchscreen cable through.
(2) Give it a good cleaning, and hit it with a coat of rust-preventive paint. This would have been eliminated if I'd been able to find galvanized or stainless steel.
(2) Reassemble and make sure no cables will wear from rubbing as the vehicle moves.
I still need to figure out a place for the button strip to go. I could hide it, I guess, or maybe I can build it right in the dash bezel that slips over this.
Post-Mortem -- Screen Mount
This seems like a good time to do an assessment of what I learned building the screen mount. What would I do differently, if I had it to do all over again?
(1) I'd design the whole thing in Google Sketchup or one of the free CAD programs, then just build to plan, instead of building a piece and then building stuff to make it work.
(2) I'd build the whole thing in the lightweight galvanized steel to test the theory. That stuff is so easy to work with that I'd have saved time in the long run, because I'd have seen the conflicts in the mockup.
(3) I'd use galvanized or stainless steel, instead of plain old cold-rolled steel. With galvanized or SS, there's no paint necessary.
(4) I'd build a little adjustability into those back tabs, and maybe all the tabs, because the dash components aren't perfectly straight. Just 1/8" or so would work; I'll need to add two 22-gauge shims under the rear driver's side tab to get this in perfect alignment, even though my mount is dead straight. I needed to make some allowance for the factory variances. In the automotive industry, variance is pretty common -- ask anyone with a body shop.
(5) I'd consider designing the screen support rail and the PCB to be a single bent piece, instead of two pieces. In this build, the rail was an afterthought (see Post #45).
Overall, I'm pretty happy with the result. It's strong enough and accurate enough that it should work for a long, long time.
I took some pictures of the wires coming off the top left face and the lower right side of the screen to help anyone else planning to use the Lilliput 10.4" without its case:
Click images to enlarge.
I had to modify the bracket design to allow for these wires.
How do these wires connect?
If you've uncased your Lilliput 10.4", Model 1042, I could use some help. In disassembling mine, I accidentally (violently) detached the four small wires that appear to be for the touchscreen. They look undamaged. There are two yellow wires and two black wires. I need to reassemble the plug they go into, and wonder if anyone can tell me how they connect. Here's a picture of the wires -- in order as they come off the board -- plus the two plug components, plus the board they plug into.
Click image to enlarge.
EDIT: I got this answer in the LCD/Display forum:
I added this information to the Everything You Wanted to Know About Your Lilliput FAQ.
It's time to get back to work on the bezel. I'll continue to practice plastic welding until I get to the point where I can avoid warping and get an acceptable finish. But I'd like to use adhesive for such things as attaching mounts, and maybe other ways. I've been researching polyethylene adhesives, and so far I've found three that I've considered.
The first, Plastic Weld, sounded really good. It's manufactured by Solder-It Corp. in Cleveland, OH (which also has some other very interesting looking products). I didn't see enough information on their website, http://www.solder-it.com/solderpaste.asp, so I tried to contact them. Unfortunately, my attempts have all failed. Their email bounced as undeliverable, and the phone has a message that refers me to a NY number that's disconnected. If anyone has any information on the product or where to find it, or if you happen to know that they've gone under, or gone on vacation, or something, I'd sure appreciate the information.
Second, there's Poly-Bonder, from Mr.Sticky's, available at some Ace Hardware stores and TAP Plastics, among other places. This 2-part product requires that we heat-prep the surfaces to be bonded with a torch. It's $9.95 for 30 grams (just over 1 ounce) of hand-mixable material. The same product in a dispensing system is much more convenient, but also more expensive -- at TAP Plastics, it's $21.75 for the 57-gram container and one mixing/dispensing tube, plus $44.95 for the gun, and $9.95 for 3 more mixing/dispensing tubes. Using the mixing/dispensing tubes probably also means a good deal of wasted product. Here's a video that shows the process.
The third product is 3M's Scotch-Weld DP8005 Acrylic Adhesive. Here's the product page. This product is a 2-part structural grade adhesive, and simply requires a cleaned surface for bonding. It's priced about the same as the Poly-Bonder, and requires a similarly-priced gun and mixing/dispensing tubes, with a similar waste factor. Hand-mixing is not recommended by 3M, and shelf life is six months from date of shipment, if refrigerated.
Initially, I expect to try the Poly-Bonder, simply because I can hand mix it and see if it does what I want. Now I just need to find it locally . . .