Scion xB '06 -- in-dash screen -- details, pictures, links - Page 6

turbocad6 · 04-14-2008, 11:31 AM

it's very possible that when you add the screen there is not enough power anymore... try just the screen by itself to see if it's a power issue

rdholtz · 04-14-2008, 11:36 AM

Thanks -- I'll give that a shot. I'm running both PC and screen off the M2-ATX, and it should have enough juice to do it, since there's not a lot of power grabbed by the PC, with a 25W processor and a single SATA drive. Still, there's no sense in ignoring an obvious solution. I'll test that tonight.

rdholtz · 04-15-2008, 11:17 AM

More Screen Testing

Separate power didn't change anything, nor did using a powered hub to run the USB connection. Looks like there's something fundamentally wrong here. Time to recheck all the connections, make sure the polarity is correct, and make sure everything is plugged in the way it's supposed to be. If all that fails, I'll set her aside until I can get to a repair shop, and invest my time in more bezel construction. It probably wouldn't hurt to start laying out the head unit mount, too.

I wonder if there's any such thing as a repair manual for the Lilliputs, or if this is all done by the seat of our pants.

rdholtz · 04-18-2008, 05:28 PM

Even More Screen Troubleshooting

So what's wrong with the touchscreen? Actually, what's wrong, not just with the touchscreen, but with the whole display? I let her sit for a few days to ponder, and I come to one conclusion: a dead short. This idea makes sense, because when I put power to the screen, it kills the whole system, and that indicates a dead short. In thinking about this, it occurred to me that the Lilliput case is made of plastic, and the printed circuit board is isolated from the screen itself except for the wires that connect them. I've taken everything out of the case, and have both screen and PCB mounted to a steel support frame I built, and so they're grounded together. Maybe that's not the way it's supposed to be.

There's a question that comes up: after carefully checking the way I wired the power cable to the screen, did I somehow do it exactly wrong, and feed power the wrong way through the screen? Would that produce this result? Hmmmm . . .

In the final analysis, either the monitor isn't getting what it wants from the PC power system, or it's toasted, and I'm not going to get what I want from it. Either way is a bummer, but the "toasted" scenario is a bigger bummer.

Step One in the troubleshooting process was to plug everything together and apply power. That was a miserable failure. So Step Two was to take the system off the mount and see if I got any results. Now, I know that by running this with a dead short, it's possible that I had fried the system. Oh, that would be very ugly, indeed. I was hoping it was still alive . . .

Having taken it all apart, I plugged her in. Here's how it sounded:

"Okay, she's all connected. We flip the switch and . . . aaauuuggghhh, horse puckey."

Nothin'. Nothin' at all. I tried switching some connections around. Still no joy. But, on the other hand, there was no big streamer of smoke, either.

I guess the next trick is to do some multimeter checks and see what we have. That'll wait 'til I go back up to Atlanta where Ozzy71, the electronics guru, lives. He knows bunches more about this stuff than I do. He informed me once that electronics devices run on smoke. "You let the smoke out of 'em, they don't run any more." And I've lived by that wisdom ever since: don't make 'em smoke.

What's Next if it's Dead?

If she's dead -- smoked -- then I'm going to take a hard look at two ideas: a regular, non-touchscreen LCD panel (with a touchpad or the already-planned joystick/trackball), or a nice, bright transflective (transmissive-reflective) touchscreen display. The plain panel is lower cost, but the transflective display is much better in the Ooh and Aah department.

I may consider pulling back to a 9-inch monitor, as well; that wouldn't change the cost very much, wouldn't change usability a whole lot, but it might make the bezel production somewhat easier. I guess I'd have to ask the mods to change the name of the thread, wouldn't I?

Rather than letting this be a complete roadblock and putting the project on Hold for a couple of weeks, I think it's time to make a mount for the head unit. Whatever I do, the HU will be moved, and it has to attach to something. That mount is where we're headed next.

rdholtz · 04-21-2008, 05:37 AM

Moving the Head Unit

To make space for the screen -- whatever screen I end up with -- the head unit has to move. It goes to the bottom of the dash, in the space previously occupied by the cubbyhole, ashtray and lighter. There's just room for it. Here's the original dash, with the HU up on top, and then a closer shot showing the holes made by removing the HU above and the cubbyhole/ashtray/lighter unit below::

Click images to enlarge.

Finally, here's the dash with the HU moved down -- but not mounted to anything -- and the screen mockup in place, first from the driver's viewpoint, then looking in the passenger door:

Head Unit Mount

Now the challenge is to mount it this head unit. I want to use a system similar to the OEM support: two sheet metal brackets that are bolted into the sides of the HU, and then are bolted into the vehicle.

In the space where I want to put it, there's a solid fastening point on the left side, where the Phillips-head bolt attaches the dash to the dash sub-frame:

(That cable bundle is well behind the bolt, although this camera angle makes it look like it attaches there.)

That fastener only makes the left side work. Almost everything else in the area is part of the dash, which means it's only plastic. That's not the best support material for a relatively heavy unit. By pulling back the carpet on the right side, I see that, down at the floorboard level, there's a steel bracket held on by two Torx T40 socket-head fasteners:

If I can build a bracket that attaches to those two points, I'll have a total of three points to mount on, and that should be solid.

(If you're wondering what those black plastics things are in the last two pictures, they're ducts sending heat and a/c to the rear seats.)

Space in this location is relatively tight, and the bracket down the right side is going to be a long one. It may be wise to make the bracket that bolts into the right side of the HU separate from the part that extends down to the floor. That way, I can put the long lower right bracket in first, mount the side brackets on the HU, and bolt the HU in place.

That's the plan so far. Now I'll build some mockup brackets from cardboard, because it's so easy to work with. Then, when I have something that looks like it will support the HU -- and that I can get in and out of the dash -- I'll build them in light sheet metal, then 22-gauge steel. The light sheet metal isn't a necessary step, but it lets me test the theory in a material strong enough to do a test installation. If it works in that material, or if it works after some refining, the test piece is a rough template for the final steel part. Doing it in the light material lets me make mistakes that are easy to correct, and means the final part won't have suffered through extra bends and unbends, which weaken the material, and it won't look cobbled together. Even if it's hiding behind the bezel, I want it to look OEM and be at least OEM quality.

rdholtz · 04-22-2008, 06:03 AM

Head Unit Bracket Material

I'll make one change for this part of the project: instead of using low-carbon steel (LCS) like I did on the screen mount, I'm going to find some 20- or 22-gauge galvanized or stainless steel, to eliminate painting.

My favorite source for galvanized steel is old computer cases. If you have a computer store in your area, especially one that does repairs, you can probably get an old case from them, and likely for free. When the power supply blows on some computers, the replacement power supplies are so expensive that it can be cost-effective to simply sell a new case (that comes with a new power supply) and transfer the components. The shop winds up with an old case with a dead power supply, and that case is headed for the dumpster, because it has no significant value. Ask at such a shop -- especially if you're already a customer -- and you could walk away with a dead case that has lots of usable sheet metal in it. Take a couple of them if you can stash an extra.

You can also find galvanized sheet metal at hardware stores, Lowe's, and Home Depot. I use galvanized duct material for test pieces -- the interim "light sheet metal" phase I mentioned in the post above.

And an interesting source for long pieces is galvanized steel studs in the building materials section. The studs themselves are a relatively light gauge. For heavier gauge material, the galvanized steel stud drywall track is good, but I found that only the web portion works well. The flanges are apparently work-hardened in forming, and they don't like to bend.

The fall-back position is to just use LCS. It's cheap and easy to find at hardware stores and home centers. With my dash opened up, I see there's lots of LCS in unseen interior parts of the Scion -- the entire dash subframe is raw steel, and there's very little corrosion on it. It's common to use LCS in contemporary vehicles, and these parts seem to survive without corroding into rustheaps.

Painting LCS metal parts that are hidden is not a big deal, anyway: I give them a good rubbing with a Scotchbrite pad, wipe them down with acetone, and hit them with a coat or two of quick-dry acrylic rattle-can spray paint. They're ready to assemble and install in less than 30 minutes, although I usually let them dry overnight before doing anything else with them.

roflcopter · 04-22-2008, 10:41 AM

what about aluminum? its easy to bend and its non-corrosive. with the amount of metal actually needed, i cant imagine a sheet being too expensive. especially if purchased from a home depot or lowes.

rdholtz · 04-23-2008, 04:24 PM

Quote: Originally Posted by roflcopter

what about aluminum? its easy to bend and its non-corrosive. with the amount of metal actually needed, i cant imagine a sheet being too expensive. especially if purchased from a home depot or lowes.

I agree -- aluminum is very nice to work with. The finished product doesn't "rust", and, even if I were going to paint, aluminum would be great, because it takes very little preparation. Galvanized steel has to be washed well with phosphate. Aluminum is more expensive than steel, because we have to use a heavier gauge to get the same strength.

I happened onto a panel from a discarded computer, this time from a big server, and it doesn't appear to be galvanized steel, but rather "aluminized" steel. That means it's been hot-dip coated with aluminum-silicon alloy, and it has the no-rust benefits of aluminum with the strength benefits of steel. It's the best of both worlds.

There's enough steel for the head unit brackets and a bunch of other stuff in just one piece. Hidden or not, these parts won't need paint.

rdholtz · 04-25-2008, 04:46 PM

Steel Panels

Here's a picture of that steel cover panel I'll use for the head unit mounting system. It's painted dark gray on the outside (the streaks you see on the inside appear to be overspray from the powder coating operation). It needs to be cleaned, but I'll happily trade some cleanup time for the zero-cost price tag.

Along with the cover panel was a panel of perforated aluminized steel, also free. It was formerly the cover to a huge power supply. It would be terrific for the ends of my computer case, but I'm not going to take the completed case apart and redo it. It might be interesting to build a whole case out of this material. I hate to think what I'd pay for a perforated panel like this if I went to buy it. We'll need it for something . . . it can go into storage until then.

Click image to enlarge.

rdholtz · 04-26-2008, 07:54 PM

Revised Head Unit Mounting

As is typical of new designs, the head unit mounting has changed again. As I began to cut cardboard pieces to make these bracket mockups, I noticed that the left bracket would be pretty easy, so I decided to make that one first. I mocked up a cardboard piece to attach to the left side of the HU and go down to that big Phillips-head screw. That's when it dawned on me that a shift in the design would result in a better system. "Ahhhh!", I said out loud, "how 'bout a deck and rail system?"

That's what I'm building: a bolt-in system that will support the head unit separately from holding it in. The HU slides onto a support deck that holds it in position laterally and vertically. and tabs on the back of the HU bracket are fastened to the deck so it's held in place fore-and-aft. If the mount is solid, the heavy head unit will be, too.

The huge advantage to this system is that I can build the whole thing without the head unit in place, so the workspace is much roomier. It also means I only have to fasten one time to the Phillips and Torx fasteners, which are at odd angles and are hard to reach. Then the HU can be removed and reinstalled easily.

Cardboard Version

Cardboard is easy enough to work with, and it's a lot faster than metal when I'm just trying things to get some concept of fit. For most of this work, I'm not using corrugated cardboard, like boxes are made from. This is posterboard, about 1/16" -- 1.5mm -- thick. It only takes scissors or a knife for cutting and a Phillips-head screwdriver to make holes. I can do all that kind of work in the car, because the only mess is cardboard bits, so it's easy cleanup. If I need to extend a part, I can trim and try new pieces of cardboard until I get the fit I want, and then make a new one from a single piece. The biggest problem with cardboard is that it's just too flexible to provide very good accuracy. Still, it gets me into the ballpark, and lets me try things out until I get a concept that looks like it will work. The parts look rough in the pictures; I didn't try to make them pretty -- just functional.

Step one was to make a mock head unit for positioning, so I could see how high the deck should be and what angle to use for it. The cardboard mount can't support the actual HU, and it's no fun to try and support that heavy weight in position while I do fit checks, so this is a good substitute. I chopped down a Woot shipping box to the exact dimensions of the head unit. This the one place I used corrugated material, because it was handy. There's no top, and I cut one end open so I can see how it mates to other surfaces:

Click images to enlarge.

Then I made a cardboard deck to go under the HU, and added a cardboard leg to connect it to the Phillips-head screw. I bent the back edge up; that will provide strength, and the HU will slide back against it. I also extended the tab out under the deck to provide stiffness. I put temporary corners in the back to keep the back bend in position (they won't be necessary in the metal versions), and cut a hole for cooling to match the holes in the HU. Cutting the hole -- rather than just marking it -- lets me make sure everything will work together. In doing the fitting, I used the actual HU, not the mockup; the mockup is just for the in-dash fit checks.

Here are two views of the cardboard deck and its left leg. They're inverted in these shots:

Here's how the top of it looks:

Next I needed to support the deck on the right side, so I built a leg running up from those Torx T40 socket-head bolts. The bottom of the leg has tabs that the Torx fasteners go through. Next, I added a piece on the top where it would meet the deck; it took several tries to get the piece just the right shape. Finally, I added an extension to support the deck and provide more stiffness. Here's the original part, inverted so you can see the tabs more clearly:

Click images to enlarge.

Here's the opening in the dash with nothing in it, and then with the deck on its two legs. You can just barely see the legs sticking down from the front lip.

The pink area at the top of the left picture is apparently my finger. Oops.

That's it so far. Next I'll mock up the HU brackets.

rdholtz · 04-28-2008, 04:49 AM

Head Unit Brackets

The brackets that connect the HU to the deck bolt into the sides of the head unit, and each has a flange that extends under the HU. There's enough gap between the flange and the HU that the deck can just slide between them. The flanges lock the HU in place both laterally and vertically. Here are the brackets, then the brackets mounted on the HU (the HU is inverted here):

Click images to enlarge.

Making sure there's just the right gap between the flanges and the HU will be critical in making this system fit, so it will be one place I take plenty of time to make it exact. The gap should be very slightly larger than the thickness of the deck, for a nice, tight fit. The light metal version will be a bit loose because the deck material is thinner.

I'll put some tabs at the back of these brackets, then build tabs on the sides of the deck to match. After drilling matching holes in them, I'll put speednuts on the deck flanges. After installing the head unit, I'll attach the brackets with short sheet metal screws, and they'll hold the HU in position fore-and-aft.

Next I'll clean up the right leg design, and then I'll start on the light sheet metal version

rdholtz · 04-29-2008, 06:58 AM

Revising the Right Leg

This is a development process, and sometimes sleeping on an idea makes it come up cleaner. I wasn't very happy with the right leg design two posts above; it had too many bends and notches, the bottom tabs weren't big enough, and it looked weak. I had to live with the middle notch, but I cleaned it up and added some extra depth. Here's the progression of that leg (it's inverted in these shots):

Click images to enlarge.

The first picture shows the leg after a bunch of fitting and making something that worked from several pieces. I cut the second part after tracing the cobbled-up piece, so it would retain its shape -- the tape has too much "give" in it to stay aligned properly. In the last picture, I added some small pieces to it to make it stronger and add width at the bottom for the mounting tabs. I didn't make a new part. The additions were cut to fit and taped on because they aren't structural. The part is still a single thickness of cardboard, and easy to trace, so there's no need to make a "final" cardboard sample.

I'm still a little concerned about its strength at that thin section in the middle, but I'll build it as is and see how strong it feels.

Now it's time to start cutting sheet metal.

rdholtz · 04-30-2008, 07:44 AM

Making Metal Parts

The head unit is relatively heavy, and it's cantilevered out from the mount points, so these support parts have to be strong. In making them, I have to consider not just the normal load of the head unit sitting on them, but vertical acceleration loads -- such as the load I impose by going over a big unexpected bump (where I grew up, that was called a "Whoop-Dee-Do", unless it was really rough, when it was "Holy $#!^!").

The cardboard version of these parts gets me a pretty good fit, and it also lets me see where there may be weak areas. The steel I'm using -- both the light galvanized duct material and the final 22-gauge steel -- is still relatively thin, so I add strengthening flanges to keep the parts from deforming under load. Although the flanges may not always be necessary, a little extra metal is cheap insurance and it adds very little weight. It's better to over-engineer than get an unpleasant surprise. If I can make these parts strong in light sheet metal, they should work fine in the heavier steel.

I lay out the metal parts one of two ways: by tracing the cardboard shapes, or from a relatively formal sketch with all the dimensions. I trace the odd-shaped cardboard parts -- like the right leg -- and add material where I need flanges. I start at 1/2" flange width, but can reduce that amount if there's a fit problem. Where parts have very specific dimensions I have to maintain -- like the deck -- I do drawings. The deck has to fit precisely under the head unit, so, rather than tracing the cardboard deck, I simply make a drawing with all the necessary dimensions, and lay the part out from that, scratching the design into the metal, keeping it aligned with a steel ruler and a square.

The light sheet metal test parts can be cut with sheet metal shears, whereas the heavy sheet metal final parts get cut in the band saw because the material stays flatter; the shears tend to bend the parts. Both types of parts get bent on the little sheet metal bender and drilled on the drill press. I do a little edge finishing on the light parts, mostly to keep from cutting my hands up while I'm using them. For the final parts, I edge-finish several ways: on the grinder/buffer, with a rotary tool, and with hand files.

I do all the manufacturing work on the metal parts -- including trimming and filing -- outside the car to keep chips out of the carpet.

Radiusing Corners

One of the good tricks in working with sheet metal is to avoid cutting a hard inside corner. When two cuts come together, it's a good idea to drill a small hole at the meeting point before starting the cuts. The outside edge of the hole should be right at the cutting line. The result is a radiused corner, which is much less prone to fatigue cracking. If drilling isn't possible, then careful filing to produce the radius works well. Although outside corners don't develop fatigue cracks, I round off them off, too, but that's more to protect my skin and make the parts look OEM.

Choosing Fasteners

One extra concern in building these parts is the fastening process. Pop rivets are fine for most of the fastening I'll do here. But I don't want the rivets to be "bumps" on the deck where the head unit slides onto it, so I have some choices:

(1) find a way to place them so they don't get in the way
(2) countersink the holes and use "pop" rivets
(3) countersink the holes and use solid rivets
(4) countersink the holes and use short countersunk head bolts and either locking nuts or regular nuts with lock washers.

The countersunk solid rivets give the smoothest finish, but they're a pain to install. Real rivets take practice, and this is just a hidden part, so I'll do some testing with countersunk pop rivets. Where the parts will later be disassembled -- like the junction between the right leg and the deck -- I'll use bolts.

The fastening of the leg to the deck won't ever be permanent, even in the finished part. I made the leg as wide as possible for strength, and it takes some work just to get the leg alone up into the dash. If I assembled the leg to the deck before installation, I couldn't get it in. Since one of the goals in this installation is to be able to go back to stock, I'll use removable fasteners -- the countersunk head bolts -- at that joint.

rdholtz · 05-01-2008, 07:01 AM

Do I Really Need a Built-in DVD Unit?

I've been considering whether I should put a DVD unit in the dash. It would have to go on top of the head unit, because putting it below might create a conflict between the DVD tray and the shifter. While it would be simple to build a sheet metal case for it that attaches to the HU brackets, it would also mean redesigning the HU support system, because the HU would be about 3/8" lower. I'll have an audio DVD player in the HU, so it all came down to deciding whether I could imagine needing a PC DVD unit in the car so often that a portable unit wouldn't be sufficient.

Decision: no built-in unit.

I'd prefer to run a DVD unit -- even a portable one -- on IEEE 1394 (Firewire), because it's more reliable for high-power-draw devices. That means I need to get a portable case for the DVD unit. It also means I need to add a Firewire port to the PC, but there's space to do that using a low-profile PCI card. The card will require two more holes in the PC case, though, so Firewire and the DVD get added to the list of future enhancements.

That means I can keep right on going with the HU mount as planned.

rdholtz · 05-01-2008, 07:03 AM

Building the Deck

The first metal part I made is the deck. This is a part that's unlikely to change in the design, so I decided to go directly to the finished part, instead of doing the light metal part first. I've added a strengthening flange at the front, and I also added the mounting tabs I mentioned. Here's the drawing of the part, produced in Google Sketchup:

Click images to enlarge.

I normally use pencil sketches for the parts, not Sketchup drawings, but the output from a quick Sketchup drawing is a lot easier for you to read in this worklog.

The material for this part was previously the bottom paper tray panel from a dead fax machine. It's my favorite material -- stainless steel. Here are the cardboard mockup and the new metal deck:

I cut the cooling hole in the middle of the deck by drilling some holes and using a saber saw to cut the rough opening (it was a really rough opening -- the saber saw blade didn't like being asked to cut the stainless steel). Then I put the grinding bit on the Ryobi rotary tool, which is an 18V-battery-powered version of the Dremel. That got the opening pretty close to finished size. I did the final work with a hand file.

Where there are multiple bends to make on a part, as there were on this deck, I have to plan the order of the bending, or I may get the part to a point where it won't fit into the bender and I need to go to the vise. For small bends, that's okay, but the vise doesn't produce the clean, finished quality I like. For long bends, the bender is indispensable. On this piece, I bent the tab legs first, using the metal bender, and then I bent the tabs themselves in the vise. That gave me just enough room to bend the long back flange in the bender, and I finished with plenty of room to do the front flange the same way.

The brackets are next.