How-To: Make a solid-state A/V switcher

Ben's Solid State A/V Switcher. Comes in any color you'd like as long as it's black.

As you probably recall we recently had several articles on the Wii laptop which, of course, has Virtual Console game emulation. But what about people who'd prefer to have, say, every system they own hooked up all at once to one TV? Or a full-featured standalone DVD player and an Xbox 360, both using component video? This can become problematic input-wise, but not if you have a solid state A/V switcher!

While "solid state" may bring bring to mind electronics from the 60s (or, in some cases, yet-unreleased flash hard drives), but in this case it simply means the actual switching is done with circuitry, not mechanically. Ironically, the circuits are activated with a mechanical switch, but they could be controlled electronically if you were so inclined.

In this How-To we'll show you how to wire up your own A/V switcher which you can expand and use any way you'd like, for composite, S-Sideo, component, even VGA signals. Sure, you can buy a newer, really expensive TV's with multiple inputs (even component), but for those of us whose credit cards aren't quite up to that challenge, more inputs for less cash would be rather desirable. Let's get started!

For this project's example we'll be building a 3 input, single output composite video, left / right audio switcher. This will allow us to, say, switch between SNES, NES, and the God of War II adapter (aka PS2) using the single input on the back of the TV. Quality. We'll also explain how to wire up a VGA or S-Video port as well.

Parts list

Here's the electronics we'll need to build this project. Quantities are noted as they will vary depending on how many inputs we want.

Bus switch - Digi-Key part # 568-3619-5-ND. We'll need one of these for every input you wish to have. They're pretty cheap, about 56 cents each.
10k resistors - Digi-Key part # 10KQBK-ND. We'll need one of these for every input.
1k resistor - Digi-Key part # 1.0KQBK-ND. Just need one of these.
Pushbutton on/off switch - Digi-Key part # 519PB-ND, Radio Shack catalog # 275-1565. We'll need one per input. Any switch that can stay on or off will work, these are a couple good choices. The Digi-Key model is much cheaper of course.
7805 voltage regulator - Digi-Key part # 497-1443-5-ND, Radio Shack catalog # 276-1770. Converts the voltage from the power supply down to 5 volts for the circuitry. We just need one.
Heat Sink - Digi-Key part # 294-1108-ND, Radio Shack catalog # 276-1368. Sucks excess heat off the 7805 regulator. You can use a chunk of scrap aluminum if you wish, even a PC's expansion slot cover with a hole drilled in it, as this project isn't going to generate much heat. Again, just one is needed.
Project box - Radio Shack catalog # 270-1805. We grabbed a large one so we could add more ports in later on if we wish. Any plastic box will work, go nuts and be creative. I'll let you guess how many are needed.

Here's the Digi-Key part numbers of any jacks you might need. Get as many as you plan to use for inputs and the output.

Yellow RCA jacks - CP-1415-ND
Red RCA phono jacks - CP-1413-ND
White RCA phono jacks - CP-1414-ND
Blue RCA phono jacks - CP-1416-ND
Green RCA phono jacks - CP-1417-ND
S-Video jacks - CP-2440-ND (also called a mini-din)
VGA jacks - 215FE-ND (also called a d-sub 15)

Other things you'll need:

Thin wire - Such as ATA-33 hard drive wire. To connect the bus switches.
Low wattage soldering iron
Solder - As usual we suggest the thinnest stuff you can find.
An old wall-wart DC power supply - These usually range from 5-15 volts, 9 is very common. Any old supply should work, such as from a Zip drive, game console, cell phone adapters. Look for "DC output" on the label, as well as a mA rating of at least 200. This relates to how much current it can supply. You can also power this project with batteries if you wish, for whatever reason.
Power switch - For the entire switch box, "main power" you could say. Any small switch will work, or you can skip it and have the switcher be always-on.


Don't miss the bus

This project works using bus switch IC's (integrated circuits or "chips"), in this case, 8-bit switches. Each switch has 8 inputs and 8 outputs, actually arranged as a pair of 4's that can be switched on or off separately. By connecting multiple bus switches together and putting all of the outputs on the same line (or bus) we can build a multi-input, single-output switcher.

The term "bus" refers to a group of signals, typically in a computer, that carry data. For instance, in a 8-bit computer like the Commodore 64 the data bus consists of 8 traces that interconnect most everything on the board. For our project the bus will connect to all of the outputs of the bus switches and the output jacks. Each set of input jacks is connected to, get this, the inputs of a bus switch. Thus, whichever bus switch is enabled, that's the signal that gets outputted to the main bus and to the output jacks.

Wiring the bus switches

Here's the trickiest part of the project. Like most ICs these days, the bus switches are surface mount and thus are harder to solder manually than the DIP sockets from the olden days. We covered soldering like this back in How-To: consolize an arcade PCB but here's a recap:

The 20 pin bus switch integrated circuits

• Clamp the IC in something to hold it steady, such as a "Helping Hands" or vice.
• Put a very small amount of solder on each pin to prep it for the wires.
• Cut 2 sections of 8 wires each from the ribbon cable and strip a small bit of plastic off the ends.
• Tin a small bit of solder onto each exposed wire.
• Hold each wire to each pin and heat it to connect the pre-soldered parts together. For best results, start on the center wires and work your way out.

As with many of our How-To projects, making your own circuit board can be a big help. Now let's talk about how this bus switch works.

How to wire the bus switch in many different ways

Above is a drawing of the bus switch, with the pins relabeled to make them a bit more clear. There are actually 2 switches in this IC, labeled here as A and B. When the Enable pin (A or B) is pulled LOW (connected to GND) the appropriate inputs are connected to the outputs, ie, Input A-1 connects to Output A-1 and so forth. The line above "Enable" in the drawing means it is active low (activated when pulled low) When the enable pin is HIGH (connected to +5 volts) the inputs and outputs are disconnected.

Thus, one of these IC's could act as (2) 4 signal switches, such as composite and left and right audio, or S-Video (luma and chroma) and left and right audio. To use the switch with all 8 lines at once, simply wire Enable A and B together so they are both activated at the same time.

When a switch is turned off (or open, not engaged) the output pins are at high impedance, which basically means they're neither on nor off and won't affect whatever else is on the bus. This is what allows us to use multiple bus switches on the same bus and is similar to how a computer memory map works.

The following examples will show how the bus switch can be wired for a variety of video input types. We'll talk about hooking multiple bus switches together and the rest of the wiring (such as power, ground and the enable switches) later on. In every example "Bus Out" refers to the signals / pins that will connect to the main output jacks on your video switcher. So no matter how many inputs you have, all the Bus Out signals go to the same place. (That's why it's called a bus, and you're probably already sick of the word.)

This illustrates how to hook up two inputs, consisting of S-Video (Chroma and Luma) and stereo audio, to the IC with 1 ouput. The Bus Outputs (colored green) are connected together, this is because they are both on the output bus to the output jacks. To connect another 2 inputs, we'd simply use another bus switch and attach its bus outputs to the same place. All the bus outputs end up at the output jacks.

Note how the bus outputs are at opposite sides of the chip, thus they can be easily interconnected using a thin piece of wire between them under the IC.

Here's a slight variation of the first design, this time just using composite video (single wire). Note how some of the pins are unused since we're only using 3 inputs this time.

Above is a drawing of how you'd wire a component video signal, the kind with the red, green and blue cables, like a DVD player or Xbox 360. Note how we've only used 5 of the inputs so 3 go unused. Since we're using five inputs we can no longer "split" the IC -- it can only function as one input switch. Thus, both the ENABLE pins would be connected so the pair of 4-bit inputs switch on and off together. In this configuration each input will require its own super-elaborate 56 cent bus switch IC.

Why, here's a wiring diagram for VGA + stereo audio even! This one uses 7 signals so as with the last, you'll need to connect the ENABLES together and use one bus switch IC per input. Later on in this How-To we'll provide pinouts for the VGA adapter, in case you need them. You could even use one of the signals for a S/PDIF digital audio signal.

Building a switch box

Alright now that we've described how the bus switches are wired let's put together a switch box.

Here's the project box we're using for this example. It's a bit big but gives us plenty of room to work with and we can put more jacks and switches in it later on if we choose.

First we drill out some holes for the output jacks. We put ours on the end to set them apart from the input jacks. A 3/8-inch bit will make the correct sized holes for an RCA phono jack.

Secure the jacks in place with the metal ring and the nut - it's best to clasp the nut with pliers and twist the jack as tight as possible on the outside so it won't wiggle loose over time. Use some bits of wire to solder all of the jacks grounds together (the outer shell, the metal ring part) and attach a single long wire as well. This will connect to the power supply when we get to that point.

Install as many input jacks as you'd like the same way you installed the output jacks, we put ours on the top of the box. Drill holes for the switches as well. For the type of switches listed in "Parts" we drilled 2 small holes for the leads to go into the box and then glued the switch to the surface of the case. If you use a larger Radio Shack style pushbutton you'll need a bigger hole, around 1/2-inch. Make some small holes (3/16-inch works well) next to the pushbuttons for the indicator LEDs. More on wiring those in a bit...

The installed input jacks, from the inside. Plus the IC is hanging out there on the right, ready for action.

Now let's do some wiring on the input jacks, as well as the switches and LED's.

• Wire all of the input jacks grounds together. (Same for S-Video or VGA if you're using those.)
  
• Wire one terminal of each pushbutton switch to ground.
• On the left we see a spot called "+5". This is where the input voltage will be connected and we'll branch several things off it.
• Connect a 10k resistor between +5 and the unused terminal of each switch (this will become the "enable terminal"). The enable terminal connection is what we'll hook up to the enable pin of the bus switch to activate each input.
  
• Install your 3 LEDs (we used random junk ones we had laying around) and connect all of their positive (long) leads together. Connect a 1K resistor between this and +5 volts.
• Connect the ground lead of each LED to its corresponding Enable Terminal.

Here's what all this does: 5 volts runs through the 1k resistor and into the positive terminal of each LED. (We use a resistor to avoid buring out the LED). 5 volts also runs through the 10k resistors and into the negative terminal of each LED, thus it doesn't light. It's off.

When you click down a switch, the enable terminal gets connected to ground or is "pulled low" as mentioned during the wiring section. This puts ground into the negative terminal of the LED, thus it lights. The ground also goes into the enable pin of the IC (which, as mentioned above, will be connected to the enable terminal) and activates that switch.

The 10k resistor is used as a pull-up resistor, which keeps the terminal high (+5 volts) until it's pulled low by the switch, and the resistor itself keeps the ground from having a direct path back to the +5 volts, which of course, in the words of Egon Spengler, "would be bad".

Here's what the switcher should look like thus far.

Power supply

Next let's put in a power supply, using as cheap of parts as possible. As mentioned in the parts list you can use pretty much any old wall-wart DC power supply. Some, such as those for cell phones, output between 3.3 and 5 volts and thus you won't need a 7805 regulator as the power is already within the range of what the bus switch IC needs. However most adapters output at least 9 volts (even those labeled as outputting less) so you should always test the wires with a multimeter first to find the voltage.

Cut a small hole in the box for your power switch. I'm using a slide switch from a Super Nintendo, but any small switch will do.

The knotted power cord and the switch, which is of course secured with hot glue. Stock market tip -- build a time machine, go back to before we were born and put everything you've got into hot glue. Drill another hole and bring your power supply wires through and tie a knot so they can't slip back out. This also keeps the connecting from being torn loose if, perhaps, you trip over the cord while jumping out of the way of an errant Wii-mote. Using a multimeter, find the polarity of the wires. Connect the positive wire to a terminal on the switch.

• Screw the 7805 regulator to your heat sink and put it in the box however you see fit. The bus switches don't take that much power so there's not going to be much of a load (heat), so don't bother overdoing it.
  
• Connect the other terminal of the switch to the left pin of the 7805. This is the input.
  
• Twist another long wire (colored black if you have it) to the ground wire of the power supply. Solder both of these together to the center pin of the 7805.
• Solder another wire (red is nice) to the right pin of the 7805. This is the output, and it'll connect to the +5 volt spot we talked about when we wired the input jacks together.

Here's our project thus far. As you can see, we've connected the output of the 7805 regulator to the +5 volt spot near the inputs. We've also connected the ground from the regulator to both the output jacks and the input jacks. We're ready to attach the bus switches themselves.

Wiring the bus switches to the input jacks

The wiring of the bus switches themselves was covered earlier, so here we'll just show you how they are physically connected.

Above we see the first bus switch and its first connections to the input jacks. The Vcc pin goes to the +5 volt spot, ground goes to any ground, and Enable A goes to the first switch's enable terminal. From this angle, that's the switch on the right. Remember, each bus switch has (2) sets of 4 switches, so each of these works for 2 inputs.

Here's the first bus switch again but now with the first 2 inputs hooked up. The second enable pin on the IC, Enable B, has been hooked up to the middle switch.

Earlier we talked about an "output bus" and here it is -- a very elaborate piece of copper perfboard. Laid across the pads are some bits of wire, these are the output busses, video, left audio and right audio. Ribbon cable connects these to the output jacks. Doing it this way makes wiring a little easier as you have a long strip of a connection to connect all of the bus switch outputs too and won't have excess wires between the two halves of the case.

Here's the second bus switch attached to give us the 3rd switch we need. Therefore, in this example, the second switch inside the second bus switch (confused yet?) will be unused and thus a lot of wires go unconnected. It's best to connect the unused Enable pin (in this case B) to +5 volts, so it stays off even though we don't have a switch for it.

Enable A on the second bus switch goes to the leftmost pushbutton as seen above. The inputs of this bus switch connect to the leftmost set of jacks, and the output bus connections go to the same place as the first bus switch did. Remember, a bus is connected to everything.

Our switcher is now finished and we can cram everything inside the case and test it out. Before we get to the troubleshooting here's the pinouts of S-Video and VGA adapters if you plan to make a switcher using those.

Here's a pinout of a VGA port, in case your Google is broken and you have trouble finding one because there's no internet connection to your cave.

On the same token, a pinout of an S-Video port.

Troubleshooting

If the switcher doesn't work check the following...

LED indicators don't light up:

• Check that the LED polarity is correct - long lead is positive, short is negative.
• Check that the +5 volt and ground connections are connected to the 7805 regulator.
• Ensure that the selection switches have one terminal connected to ground.

Poor video / audio signal:

• Make sure the power supply and regulator is supplying +5 volts to the bus switches.
  
• Check for short-circuited connections on the inputs and output bus.
  
• Make sure all input and output jacks have their shells/shields connected to the main ground.
• Don't enable multiple inputs at once, and check that only the input device you want to use is on to avoid interference.

No video / audio signal:

• Using a multimeter set to voltage, see if +5 or ground (reads as 0) is getting to the enable pins.
• Check the wiring of the inputs and outputs on the bus switches.
• Make sure the bus switches have their Vcc (+5 volts) and ground connections made.
• Check that your test unit (game system, disc player) is on. As a last resort you know.

Conclusion

You now have the information required to build any type of custom A/V switcher you'd like. It's a great way to hook up multiple gaming system or to put more than one device into a TV's single component video jack. Have fun with it and see what you can come up with. Remember, since the switching is done with a TTL level input signal you can control the switches with other electronics such as timers, counters, PIC's and Basic Stamps. Now go forth and multiply!

[(Unverified) Posted Mar 13th 2007 4:38PM]

Composite Inputs???

This would have been cool back in 1983.

You guys heard of HDMI???

[(Unverified) Posted Mar 14th 2007 11:29AM]

Don't be such an ass, HDMI is pretty crazy. They are incredibly hard to mess with because of the amount of wires and connections.

However, a component switch would be neat.

[(Unverified) Posted Mar 14th 2007 11:29AM]

Look at the 4th Bus diagram it is for component.

[(Unverified) Posted Mar 14th 2007 11:29AM]

Couldn't you use this as a component switch (minus the audio), since RCA, Composite, and Component are all analog?

Standingfast

[(Unverified) Posted Mar 13th 2007 5:00PM]

Or Radio Shack/Best Buy. Maybe they don't have an HDMI switch, but they do have component and composit switches.

[(Unverified) Posted Mar 14th 2007 11:29AM]

This really looks like a fun project, low cost usable product and no tricky diodes or caps.

[(Unverified) Posted Mar 13th 2007 9:02PM]

Yep!

[(Unverified) Posted Mar 14th 2007 11:29AM]

I was going to buy something like this...but now I'll make it! Thanks for the great how-to!

[(Unverified) Posted Mar 16th 2007 10:14AM]

He used Hard drive cables. If he used the ground wire for each wire used for signal (assuming its a 80 wire IDE cable) and shielded wires, cross talk really wouldn't be a problem.

[(Unverified) Posted Mar 14th 2007 11:29AM]

Pretty cool, but what's the bandwidth? Needs at least 30Mhz for 480p component, preferably 50~60MHz or more for 720p or 1080i. That rats' nest of wires looks pretty susceptible to noise and/or cross-talk, too.

How about some specs? Did you test it on a scope yet?

[(Unverified) Posted Mar 14th 2007 11:29AM]

I'll be sticking with my Joytech control center thank you very much.
http://www.joytech.net

[(Unverified) Posted Mar 13th 2007 6:09PM]

Great project idea... unlike FranktheCrank, we don't all have amazig new fangled TVs or monitors to hook up to. I find the prices for s-video splitter boxes to be pretty high for really such a low function. I might have to give it a try. For my current old school TV in the bedroom, having it all output to coax would be needed as well.

[(Unverified) Posted Mar 13th 2007 9:02PM]

id rather use one with a mechanical switch if it meant not using a PS. geez, a PS for a fing switcher?

[(Unverified) Posted Mar 13th 2007 9:02PM]

There are advantages using a solid state method. The latency for one. Prevention of interconnections for two... there are others too...


Nice write up, engadget how-tos FTW! We want MOAR MOAR!!!! How about a new engadgethowto site? One new howto everyday or so that would kick some major ass! Hackaday is dead anyway and only links to DIY sites.

[(Unverified) Posted Mar 14th 2007 10:49AM]

signal quality is a good reason to use an electronic switch.

The mechanical method will potentially introduce noise, and for analog signals, that's a bad thing.

[(Unverified) Posted Mar 13th 2007 9:02PM]

This is pretty cool but I have no experience with stuff like this so it might as well be in Greek.

The cool thing about this is that while you can easily find pre-made composite and component switches it is pretty hard to find them with more than 5 to 6 inputs and if when you do they normally cost quite a bit more than this would. I had my eye on one that could do 6 composite or component or S-Video devices with stereo or optical digital audio and ethernet and an IR remote that was like $120. While this is nowhere close to that this could still be pretty useful and much cheaper.

[(Unverified) Posted Mar 13th 2007 9:02PM]

why do engadget and autoblog writers always have to use the phrase

"comes in any colour you'd like as long as it's ..."

??

its pretty lame.

[(Unverified) Posted Mar 13th 2007 9:02PM]

It's an old-school joke referencing the original Ford motorcar. Get over it, whippersnapper!

[(Unverified) Posted Mar 14th 2007 3:07PM]

I've never really built anything before, but this doesn't look all that hard.

I want an AV (and various other connections) switcher, but I'm not about to pay $100 for the number I need.

[(Unverified) Posted Mar 13th 2007 9:02PM]

lol FrankTheCrank, you're right. It's so 1983.

[(Unverified) Posted Mar 13th 2007 11:15PM]

How about adding an infrared receiver? That's the main drawback of the switches you buy, they're all manual.

[(Unverified) Posted Mar 13th 2007 9:07PM]

A person could add infrared, computer control, really anything you'd like. Since the switches use TTL logic, any sort of electronic device can control them. It's all about switching the pins high and low.

The hardest part of this project is soldering wires to the integrated circuits, everything else is pretty simple. Yes composite is crap, but this example can be used to make whatever kind of switch you'd like.

And sorry I haven't gotten more How-To's out lately, been working on slews of secret projects ;)

[(Unverified) Posted Mar 14th 2007 10:47AM]

Would this work for a component to vga setup?

[(Unverified) Posted Mar 14th 2007 10:47AM]

like to display a dvd player on a monitor? sort of. From what I understand, it will work so long as the monitor can deal with the frequency and resolution that the dvd player outputs. It can also be used for vga to component so long as the PC outputs a resolution and frequency that matches what the TV can understand. Component and VGA use the same wiring and basic signals, but how they are driven can be different enough to let blue smoke out so be very careful if you try this.

[(Unverified) Posted Mar 14th 2007 10:47AM]

Just realized we have the same name O_o
I did not reply to my self!

[(Unverified) Posted Mar 14th 2007 10:49AM]

Naturally the CBT3244AD bus switch is not available here in Australia, can anyone suggest an equivalent?

Cheers,

Scozza.

[(Unverified) Posted Apr 9th 2007 11:40AM]

Did anyone find where to buy this part in Aus? (CBT32244A)

[(Unverified) Posted Mar 14th 2007 10:49AM]

This would not work as a component dvd to vga setup..
there aremany different kinds of component video
VGA is of the RGBHV variety aka 5 wire, seperate wires for each colour and one for each horizontal sync and vertical sync.
DVD YPbPr component variety and has sync in one of the colour wires
Further types of component analogue video signals do not use R,G,B components but rather a colorless component, termed luma, combined with one or more color-carrying components, termed chroma, that give only color information. Both the S-Video component video output (two separate signals) and the Y'PbPr component video output (three separate signals) seen on DVD players are examples of this method.

So you have different colour information and sync.

[(Unverified) Posted Mar 14th 2007 10:49AM]

Awesome article! I'll have to keep those bus switch ICs in mind for an upcoming project. Do they come in a DIP package as well as surface mount?

[(Unverified) Posted Mar 14th 2007 10:49AM]

Now see how this was done properly... in 1997!... with an old apple :)

http://www.lyons42.com/PatchBoy/PatchBoy.html

[(Unverified) Posted Mar 14th 2007 9:29AM]

I did the total and with the shiping it end up at around 30$Us+tax and a switcher cost 29.99$Can+tax. Son on that point their is not a big economy... :S
But would it be possible to have HDMI or HDVI switcher or would the same chip would work?

[(Unverified) Posted Mar 14th 2007 4:39PM]

What's with the shifting around of the order of the comment posts? My post above about bandwidth was on the first page, and BEFORE my other post in this thread, yesterday. Now it's second to last(most recent)??? WTF? Weird...

[(Unverified) Posted Mar 14th 2007 4:39PM]

Simple solution to the color problem/comments.
1. Mark and drill all holes.
2. Spray paint the pre drilled case what ever color you wish.
3. follow the rest of the directions.

J

[(Unverified) Posted Mar 15th 2007 9:42AM]

Nice... not great, but Nice.

So where is the HDMI and Toslink version?

[(Unverified) Posted Mar 14th 2007 6:26PM]

i did this using a old printer a/b switch - took a while to figure out, but it is well worth it. i use mine all the time - http://computerguru365.blogspot.com/2006/02/diy-rca-switch-box-updated.html

[(Unverified) Posted Mar 15th 2007 2:35AM]

Ditto the request for an equivalent part number for that bus switch. I can't find a bus switch anywhere in NZ/Aust (well, DSE and Jaycar don't have it, so that's everywhere!)

[(Unverified) Posted Mar 15th 2007 2:35AM]

does anyone know if it would be possible to use this with Optical audio? Could I use a few of these TORX147FT-ND and one of these TOTX147FT-ND, and wire it up to one of the leftover inputs from component? my receiver only has 1 optical in and as long as I'm making it so I don't have to switch video inputs I might as well make it so I don't have to switch audio either. So does anyone know if that will work?

[(Unverified) Posted Mar 15th 2007 2:35AM]

"You now have the information required to build any type of custom A/V switcher you'd like."

I wish. I looked into implementing a *coax* switcher about a year ago. However, most of the EEs I talked to said that coaxial works very differently and that simply connecting up the conductors wouldn't work.

[(Unverified) Posted Mar 15th 2007 2:36AM]

...OR you could spend $20 and get this nicely made one... that includes 4 inputs, composite, s-video AND a remote control, to boot, see over here:

http://www.amazon.com/gp/product/B000286Q5I?ie=UTF8&tag=mnmsprst-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=B000286Q5I

[(Unverified) Posted Mar 15th 2007 2:36AM]

wouldn't mind one that could do optical audio, or at least digital audio...

[(Unverified) Posted Mar 15th 2007 2:36AM]

kool project.

[(Unverified) Posted Mar 15th 2007 2:36AM]

This is great. Those like Frank the crank just have no imagination. This project could easily be adapted to be a input switcher for a in car video system. This would be a nice control system to switch between DVD, a carputer and a video camera.

[(Unverified) Posted Mar 15th 2007 11:34AM]

I just daisy chain all my connections with y cables :D really component? s-video? oh yes you really notice a difference on a 1990 crt with 2 video inputs and a coax connection when its solid state. uh right, why you'd really care about quality on a pre-digital age screen is beyond me. I really can't even tell the dif between s-video and progressive really. spent the 20 bucks for the gamecube thingy and was really let down. maybe my screens to small to tell the difference, but really dvi vs vga now there is night and day. all this analog stuff must die! i listen to my ipod way more than my record player, it doesn't skip, i can listen to it while driving, and jogging. but really whats wrong with plugging and unplugging stuff you lazy haxores?

[(Unverified) Posted Apr 9th 2007 12:47PM]

My son switchs cables, it takes a toll on the connectors in time. DUH ! HOSER

[(Unverified) Posted Apr 9th 2007 2:55PM]

Ok thanks for only paying attention to the last part of my comment, I was also saying that a solidstate plug into wall socket device for this was totally useless! You could just use a lot of Y cables, sure you suffer some db loss but its not that important when the cables you are using for your videogame systems are only between 3 feet and 6 feet long. Over a longer distance they would need some type of repeater but I doubt anyone can notice a difference in screen quality if their AV switcher is solidstate vs a bunch of daisy chained or radios shack type no power requiring av switcher thingy, maybe in audio they can but then why not just buy a receiver so you can listen to your games in 5.1 and enjoy a bunch of plugs. I think its a waste of electricity to make a solidstate device like this.

[cdmayer Posted Mar 15th 2007 11:34AM]

this is good stuff! i'd like to build one of these just to say I did it :P also, a more simple version (with less buses) could be used to build a switcher for your stereo if you have a lot of input sources (too many for you amp anyway).

i would really like to see a way to convert an RCA signal to VGA, so that this box could be used with both RCA and VGA outputs.

all in all, great job!

[(Unverified) Posted Mar 15th 2007 11:34AM]

Alright so the tutorial says how to make a bus for three RCA inputs to a single RCA. I understand that. But it also mentions the implementation of VGA and vidoe composite input and it also has the diagrams for the connector,however i didn't find how to wire the red, green, blue, or the chroma and luma; to the single RCA output. Or would you have to add additional outputs for these inputs? Any suggestions? Besides this oversight, the tutorial seems great.

[(Unverified) Posted Mar 15th 2007 9:16AM]

Ok so I understand the part on how to make the bus for three RCA inputs to a single RCA output. However the tutorial mentions the implementation of VGA and video composite input and it also has the connector diagrams, but it never mentioned how to connect the red, blue, green,or luma and chroma to the single RCA output. Would I have to add additional outputs for the VGA and video composite inputs? Other than this oversight great tutorial.

[(Unverified) Posted Mar 15th 2007 9:03PM]

Awesome design!!!!!

[(Unverified) Posted Mar 19th 2007 10:21AM]

Does anyone know of an IC package that can generate the horizontal and vertical sync signals from the input vga pins?

[(Unverified) Posted Mar 16th 2007 10:14AM]

if you wanted multiple outputs, would making the switches just like the input work?

[(Unverified) Posted Mar 22nd 2007 10:54AM]

i assume this would work as a kvm switch right? im worried about the 5v coming off the usb would that be an issue? would it fry the chips? or how could that be handled without linking all the computers power together?

[(Unverified) Posted Mar 16th 2007 2:43PM]

You know, the usb power thing wouldn't be all that hard to do, and it would solve the 'problem' of the people saying that they don't like wallwarts.

[(Unverified) Posted Mar 18th 2007 5:09PM]

ok that switches line level signals fom the look of it, how hard would it be to modify it to switch speaker level outputs
should just take a few transistors on the outputs or something shouldnt it?

[(Unverified) Posted Mar 19th 2007 10:23AM]

Try this:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=85505&Row=696184&Site=US

I have one of these, was going to try and hook an arcade machine to a VGA monitor with it.

[(Unverified) Posted Mar 20th 2007 1:58PM]

@omega3387 You would have to add those outputs with the inputs. I don't believe this project converts inputs to different outputs.

[(Unverified) Posted Mar 24th 2007 10:19AM]

ok so how would i get around the usb power issue? if you link the power from one computer to another there will be a bang and i am not certain that the chips can handle 5v. .........ok i think it just hit me what about only linking the power from one comp but the data lines to all? would that be bad?

[(Unverified) Posted Apr 9th 2007 11:40AM]

Is there any way of making the switches so that when you push a second switch, The first one turns itself off automatically? so that there isn't two chanels ever running together?

Is this possible?

[(Unverified) Posted Apr 11th 2007 10:10AM]

just a guy-- use a rotary switch

gilbert-- this is a project with more uses than the one stated. to me its like the howto for an idea that i havnt had yet

[(Unverified) Posted Apr 16th 2007 8:00PM]

ditta again for were to find the bus switch in australia. can anyone tell us were to get it or some kind of equivilent for it?

[(Unverified) Posted Apr 28th 2007 4:21PM]

This is interesting, but aren't you feeding a bipolar source (audio) into a single supply device? The CBT3244A specs indicate a minimum input voltage of -1.2V and a minimum output voltage of -0.5V. There's a vague statement about how these can be exceeded if current rating are observed, but audio will easily exceed that -0.5V by quite a bit. I would think this would eventually fry the chip and I'm surprised you're not seeing nonlinearities in the negative half of the audio waveforms.