This Instructable is just a simple little device I came up with over the past couple days to alleviate a problem I have with my entertainment system: my projector only has one Component Video Input, but I have two devices that I wanted to connect to it, my HD Cable box, and my XBox 360.
I'm not going to cover the basics like soldering, or how to measure accurate holes in things, there are Instructables for all that just a click away!
Step 1: Gather the Parts...
From DigiKey, I purchased the switch and Component Video Jacks, and from Radio Shack, I bought the Project Enclosure.
CP-1446-ND - This is the part number for the Component Video Jacks. Component Video colors are Red, Green, and Blue. bit.ly/9xFmbG
EG2426-ND - This is the part number for the 3PDT Switch. 3PDT means Three-Pole, Double-Throw. This means the switch switches three things at once, with a center-off position. bit.ly/cvIgvt
270-1803 - This is the part number for the Project Enclosure from Radio Shack. This seemed about the smallest size enclosure that I could use and still make it convenient and easy to stuff all the coaxes in to. bit.ly/bnNBlN
Mounting screws - I've got a couple nitro-R/C cars, so digging up some small screws was easy. Don't have any? Tear something apart MAKEr style! Or, they should only be a few cents at your local hardware store.
Mini-Coax - I work in the electrical construction industry, so this was another easy thing to come by. However, in a pinch, cut up an old set of cheap RCA cables. Whether they be audio (Red/White), audio/video (Red/White/Yellow), whatever, that will work just fine. What you need is for the coax to be of the 75-ohm variety, which audio and video cables just happen to be! You could also use TV coax, though that would be much more difficult to work with.
Drill bits - Pictured are the drill bits I used. Use the recommended sizes for the jacks and switch that you get, sizing info should be on the data sheets that are available with the parts. Also, a Uni-bit is handy to do the final reaming out of the jack holes, really helps to clean up the holes.
Soldering Iron - I used a little Weller 23-watt pen iron. You really don't need anything serious here, these are just small wires and parts.
Solder - Just some fine 60/40 will work great. I suppose you could use silver solder if you wanted for a little stronger mechanical and electrical join, but it's really not necessary.
Screwdriver, wire cutters - These are pretty self explanatory, I should hope!
Vise Grips - I used these in lieu of a proper vise, worked fine for me to grab on to parts and hold them steady.
Step 2: Make Some Holes!
Find your center-line on the enclosure, mark it, and mark where you want the jacks and switch to go.
Since I got most of the parts from DigiKey, I was fortunate enough to have data sheets available that show me the dimensions of the parts, and the centers I need for drilling out holes.
Looking at the pictures, see the penciled in circles? Those are mounting holes inside the enclosure. Something to avoid, which I didn't! Ha!
Use the smallest drill bit first, to make pilot holes, then step it up to the bit you need to make the holes the size for the parts.
Use the Uni-bit to ream out the holes for the jacks, to make them smooth, and to slightly oversize them so the jack will mount flush inside the box, and to leave room for the cables you plug in to them.
Step 3: Test Fit and Secret Method!
See that little black stick in the screw hole for the jack? Yeah, that's my method for marking the holes for the mounting screws.
It's a pencil lead from an automatic pencil. I don't have a caliper, so measuring out very small tolerances must be done in an uber-low-tech fashion! Just stick the lead through the hole, and give it a twist, it will mark the hole just fine for drilling.
Use a drill bit just larger than the screws here to make your holes for them.
Step 4: Prepare and Solder the Coax to the Jacks
First, strip back the outer insulation of the coax. Use a nice set of wire strippers to make this really easy, or carefully use a razor knife.
Twist the braid up and bend it to the side.
Then back the white dielectric. Be really careful with the center conductor. Depending on the type of coax that you use, the center conductor will be really small, and very easy to break.
Next, make a "u-turn" in the center conductor right at the dielectric and wrap that around the center conductor on the jack. Trim off excess wire.
Then solder the braid to the contact that is for the shield on the jack, and trim that back as well.
Do this for all three jacks, on all three modules.
Step 5: Prepare and Solder Coax to the Switch
Strip back the jacket and dielectric on the coax as before.
Take the three center conductors from one group of jacks and solder just the centers to three tabs in a single row on the switch.
Take the next three center conductors and solder them to the tabs on the next row on the switch, being mindful that you are matching color with the previous row. IE: blue to blue, green to green, red to red.
Do the same for the third row with the third set of coax ends.
At this point, you should now have something somewhat similar to the second and third pictures. Or, a bloody mess!
One thing I forgot to take pictures of was that you need to solder all 9 shields together. I found it was easiest to solder three from a group together and then solder a small piece of wire between the three soldered groups.
Step 6: Stuffing Everything in to the Enclosure
So, there's not much to getting all the jacks and switch in to the box, except for take your time!
Again, the center conductors are really small, so they are naturally prone to breaking.
I found it was easiest to place the jacks in to the enclosure and screw them in, then very carefully and slowly bend the coaxes around and place the switch in it's mounting hole.
Really, nothing to it.
Step 7: Test It Out!
Sorry about the picture quality, was more concerned with proof-of-concept than image quality, shot at iso 1600 just to get it done.
XBox 360 on the left, HD cable box on the right.
Step 8: Let's Wrap This Up!
Be careful as you place the cover and screw it down, your wires might stick out of the enclosure a little, you need to push gently down on the cover as you put it on. Don't just shove it on there, you don't want to force the center conductor wires and break any of them!
So, the inputs are the top and bottom rows, and the output to display device is in the center.
I plan on labeling this up with my P-Touch, probably just something like "A", "B" and "output". No need to be anything fancy, it's not a display piece, just tucked behind my entertainment center.
As usual, a little bit of "cat" may help the process along, just beware of the cautions I have listed below in the picture...
If you have any questions, leave them in the comments, or message me!
Thanks for taking a look!