Maybe you've got a few HD devices around and only one component video input on your HDTV. We've even got component out on our dear old laserdisc player. So we were rooting around in our box of parts and realized that we could make our own component video switch. HDTV switches are ungodly expensive, but KVM have gotten dirt cheap; in today's How-to we'll show you how to turn one into a component video switch.
Today's How-To is pretty easy. We'll have to make some component to VGA cables up, and trick the switch into thinking that there's a computer on each input. Our inspiration came from the VGA from Cat5 writeup
. We decided to extend the simple VGA to component video converter idea into our DIY component video switch. The mod should work as long as the switch doesn't do ANY video processing. You can also use the setup to switch between VGA and component input sources - but it will only work outputting component video. The VGA to component trick combines some signals to work, they can't be easily split apart to turn component back into a VGA signal.
Before all the videophiles freak out about the cables, this was built as a proof of concept. A better build would use quality cable components, etc. Feel free to point out your favorite high quality cable components in the comments.
The concept is simple. We'll build some RCA component to HD15 VGA cables for inputs and a HD15 to component cable for the output. We know that the Cybex can switch between VGA video sources. The premise behind our build depends on the Cybex passing component video signals in place of the VGA. Since it doesn't do any processing, it doesn't care what it's passing through.
We only need some basic tools for today's How-To. Wire strippers, soldering iron, cutters and a sharp knife. Oh, and grab a multi-meter with continuity testing. Most digital meters include one that beeps when they sense a completed circuit.
We'll have to add a 5 volt power source and some jumper wires to the keyboard connectors to make each input line active for the Cybex to switch to it. Our switch uses male HD15 D-Sub connectors for each input.
When a source is available the Cybex indicates it by lighting up the bottom LED. In reality, it looks for 5 volts on the keyboard connector. We need to trick it into thinking that our component sources are available. We could chop some keyboard connectors or we can do a little soldering.
Opening the case is easy, we just remove two screws from the bottom.
To get the Cybex to think that there's a source, we need to supply 5 volts to this pin. We can steal 5 volts from the power input or supply it from a keyboard port. It's up to you. Just jumper 5v to this pin of the keyboard connector for each input you want to use.
For our build we dug up some cheap male to male cables. We'll cut each one in half. For three inputs and an output, two cables will suffice.
This is why the cable geeks will hate this. We used some $.49 rca cables from Parts Express
to make our component ends. They're dirt cheap, and perfect for our test build.
Grab your knife and carefully slit the outside sheath. If you go too deep, you'll cut some of the wires you need.
Strip each of the leads so we can identify the wires we'll need.
Grab your meter and identify the wires you need. A helper or a set of alligator clips will make the job much easier. Check out the VGA pinout at pinouts.ru
and the component to VGA adapter pinout at the VGA over Cat5 writeup
. (We've simply used the colors of the normal connectors to designate the wires below.)
Simple VGA to RGB pinout:
- HD15 pin1 -- Red Signal
- HD15 pin 6 -- Red Shield
- HD15 pin 2 -- Green
- HD15 pin 7 -- Green Shield
- HD15 pin 3 -- Blue Signal
- HD15 pin 8 -- Blue Ground
Once you've identifed your wires, you can get soldering. We used our alligator clip helping hands to hold things steady. Before soldering each one, we double checked the pin outs with our meter.
As we soldered each pair, we marked the connectors with a Sharpie.
After everything is built, all of the connections need to be insulated. For a permanent build, we prefer heat shrink tubing. For our test setup, we grabbed the electrical tape and got busy.
That's it. They Cybex is modified, and the cables are built. Oh, and it worked. Enjoy your new found component switching freedom!
By the way: you can buy a commercial video switch for about $100, so keep an eye on what you spend building this project. We had all the parts in our junk box, so it only cost a few inches of solder and some crappy cables. (And we just had to try it.) Double check EVERYTHING before hooking it up, and you should be just fine. If you'd like this to be remote controlled, a PIC controller could be built to recieve IR commands and either input the keyboard shortcuts or simulate button presses. Let us know if you build your own!