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Topic: Design issue - How to do? (Read 2 times) previous topic - next topic

Michael L

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?


Sep 03, 2011, 05:35 pm Last Edit: Sep 03, 2011, 05:37 pm by CrossRoads Reason: 1
So you want the outputs to mimic the inputs under those three sets of  conditions?
Code: [Select]

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

Or you need to have outputs = inputs as analog signals?
Your question needs to be more clear.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Michael L

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...


Sep 03, 2011, 05:42 pm Last Edit: Sep 03, 2011, 05:46 pm by Graynomad Reason: 1
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.
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 Gray aka the GRAYnomad www.robgray.com


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 Gray aka the GRAYnomad www.robgray.com

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