Design issue - How to do?

I need some input on a design I'm working on. I need to do the following with the least amount of components, as space is an issue:

I have 3 input pins A, B and C. Two output pins 1 and 2.
And I need to achieve these three combinations:
A to 1 and B to 2
C to 1 and B to 2
A to 1 and C to 2

It needs to be controlled by an Arduino. I have been looking at NPN and PNP transistors, but it will require to many conponents.

Any thoughts?

So you want the outputs to mimic the inputs under those three sets of conditions?
Example

switch (ABCselect){
Case 1: 
digitalWrite (output1, digitalRead(inputA));
digitalWrite (output2, digitalRead(inputB));
break;
Case 2:
digitalWrite (output1, digitalRead(inputC));
digitalWrite (output2, digitalRead(inputB));
break;
Case 3:
digitalWrite (output1, digitalRead(inputA));
digitalWrite (output2, digitalRead(inputC));
break;
}

Or you need to have outputs = inputs as analog signals?
Your question needs to be more clear.

Your question needs to be more clear.

Yes. I just thought of that. Imagine a DPDT relay. I need something like it but a Double Pole Triple Throw instead. A, B and C is 16v, 10v and Ground. I need it routed to the outputs, 1 and 2, using the Arduino to do the controlling.

Better? Otherwise, I think I can draw it.. Not sure, though...

You can use transmission gates like the 4066, they will work with digital or analogue but as Crossroads says, need more info.

Voltage levels.
Current levels.
Analogue/digital.
Speed of signals.
Speed of changing from one setup to another.

and probably some other stuff I haven't thought of.

EDIT: Crossed there, you need 4 SPST relays.

A only ever goes to 1 (SPST)
B only ever goes to 2 (SPST)
C can go to either (2 x SPST)


Rob

Another question, how important is it that another combination is NOT selected?

You can control the relays with 4 Arduino outputs but if it's a big problem say for A to be connected to 2 then I may add some logic because it's easy to stuff up the programming.


Rob

4 Simple 5V/low coil current relays could be controlled by arduino outputs like this:
Be sure to have software open relays before closing others.

I already thought of the solution with four relays (or even two DPDT), but I have space issues - But perhaps, some of you can find some small relays?

You could use solid state relays (like the CPC1014N), they come in a 4x4mm package but only 400mA capacity.

That's why I asked the questions above.


Rob

Is SUBMiniature small enough for you?
http://www.mpja.com/prodinfo.asp?number=18474+RL
Takes up the space of a 16 pin DIP

http://www.components.omron.com/components/web/pdflib.nsf/0/51A3390695AC774885257201007DD58D/$file/G6L_0310.pdf
Found these at Digikey, even smaller.
Search for relay, Signal, filter your way down: in stock, thru hole, non-latching, 4.5V coil
Lot of options.