Thanks to some information posted by a very intelligent user on here (NicolasG), I think I may want to take on a project of building my own AV switcher using the MAX4315 as my logic switch for all the inputs. My ideas so far are to use plug-in cards that would have the connectors for the items needed to be switched. This way, the card could be configured for whatever type of input was needing to be switched. For instance, if you are only needing component and digital coax you would plug in cards that only had those connectors. If you needed to add for some reason composite later, just change the input and outout cards for the upgrade. That way if you only need composite for one source, that's the only card (aside from the output) would need to be changed.

I want to have 8 inputs and one output with the ability to plug in a second output card if wanted. The way I have it figured though, both outputs would be the same.

Right now I can use latching relays to hold the source selected with a momentary switch, but would like to use transitors or some other electronic switch to hold the connection for the inputs once I learn a little more.

Ultimately, I want to have composite, component, L/R Audio, S-Video, Digital Coax and Toslink all available for switching. From what I understand, I can use the MAX4315 for each of the separate inputs (IE 3 for component, etc...) and I can use the Ax input lines on the MAX4315 to select the source using binary selection. What I don't know is how to set the lines? So I just use ground or +5v applied to the lines to get the result? I've got the binary part figured out - A0 and A1 selected would give me source number 3 with the first source counted as 0 or source 4 if you count the first source as 1, etc...

Also, I don't know where to get the TOSLINK connectors from or how to implement them.

I would also like to have a display and a remote for the unit as well, but these unfortunately are beyond what I am able to do at this time but I'm very willing to learn.

Any information that anyone can provide or any ideas that anyone would like to share would be appreciated. While I am new to this forum and new to designing circuits, I do have a small electronics background to base what I learn on. In other words, I know enough to be REALLY dangerous!!!! :D

If I am able to complete this to my satisfaction, I might work up a price and sell this, but honestly, for right now, this is to teach myself some new tricks. I haven't tried anything this ambitious in a few years and I've got the want to learn bug again!

Many thanks!

Sorry for not replying earlier, didnt know the thread had been created.

So yes, thats the simplest and most modular approach (what you described)

There is one main system where all the modules get fitted into.
To keep things a little simple, you limit the switching to one output, and say 8 inputs.

The main system (cant think of a better name) handles several things
- Provide Control logic of Address lines for control of inputs
- Accept/Receive IR + other types of signals to control switcher
- Display in some form which output is currently selected

The main one is the first, because these control the actual switching devices in the module to select the input line.

A simple microcontroller can solve this function, Im a PIC user, but Atmels will work as well. Something in the $1-3 range should do the trick.

I can wip up some code that based on input, controls the outputs (a simple serial-parallel ic such as the 595 will do the trick for controlling the address lines based on a single MCU line)This can be pondered upon and the best solution selected, why ?
Because theres different approaches
A. Each module has 8 lines that select the input, only 1 line high at a time
B. Each module has 3 lines that select the input, binary address
C. Each module has a MCU, and using a common data line we pass commands to the module.

B. Would possible be simplest, as most MUX's already use this type of control.


For switching analog audio, you can use 4050 line (4053/4052/4051).

For TOSLINK, im not quite sure, it would depend on the speed that this spec works at. If it is low, then we can get away with the same logic chips being used for analog audio (yes this can add interference as we convert light into electricity and back - so this will need to be properly designed to avoid as much interference as posible)

I have to look back at my joytech, but they are ether using relays or the 4053's to switch the Optic's. Most likely the 4053, as there is only 12 relays and 3 network switch (1 network = 4 lines)


So where to start, come up with the 'modules' and test them to make sure they are working properly.
Probably start with the easiest, the Analog audio which uses the 4053.
Then give the MAX component video switch a try, these are more hard since the IC's are small and wiring 16 wires to is hard, and can introduce static if not built on a PCB.

To control the address lines on these, and the max's. You can simply bring down to gnd, or bring up to 5v via a 10k resistor.