Using an SPDT to change a Bi-colour LED (Resolved)

[Sibob]

Hi guys,

I've just put this together and it works great:



However, I thought it would be great to have a Bi-colour LED so that I know when it's in feedback mode as opposed to just true bypass mode.
How do I go about wiring that up?  , I've got the LED ready to go, and it works just on and off, but I can't get my brain into gear to get it to change colour via the SPDT?

Thanks
Si

[catfud]

Check this out for what looks like a sane approach if your LED is the bipolar sort of bicolour LED (if the bi-colour LED has two pins).

This is the kind of thing that *should* work (click on the little pic for the full-size version):

If it's the common anode/cathode kind of bicolour LED (in other words if the LED has three or more pins) it may need a different approach though.

Disclaimer: I've not tried this, happy to be corrected if it's off the mark.

[Sibob]

Thanks for the reply, appreciate it, however would that not just operate the two colours via the 3PDT?
I want the 3PDT to act as the on/off with one colour (standard), then whilst on, the SPDT switch to switch between colours when it switches functions.

Cheers
Si

[catfud]

Thanks for the reply, appreciate it, however would that not just operate the two colours via the 3PDT?

Yes, it would. I should have paid more attention to the question.

I want the 3PDT to act as the on/off with one colour (standard), then whilst on, the SPDT switch to switch between colours when it switches functions.

What sort of bicolour LED do you have?

[Sibob]

Looks very much like these:





Cheers
Si

[catfud]

Looks very much like these:
...

I've not played around with the common cathode type.

But if you had the bipolar (I've been playing with the bipolar LEDs which is why I'm focussing on these) substituting a DPDT where you have an SPDT should work:



I suspect that using the DPDT will give you the options for the common cathode type too, but tonight is too late for me to think on that one...

[Sibob]

Hmmm, so a DPDT might be necessary?!

Cheers
Si

[catfud]

Hmmm, so a DPDT might be necessary?!

I think it would help, given what you want to do.

I think something like this would work for that circuit, which isn't a million miles away from the bipolar wiring a few posts back:



(Disclaimer again: I've not tried it, but it looks like it would work to me)

[Sibob]

So I've been working to this diagram:



But I get no LED light whatsoever, let alone switching colours.
I've re-tested the LED in a test circuit and it works fine. I'm using a 2.2k resistor. The DPDT switches between true bypass and feedback no issue.

Any thoughts? I'm writing this from work, but I think I might redo the entire 3PDT to be sure.  What do I read on the 3PDT with a MultiMeter?

Si

[muddyfox]

What do I read on the 3PDT with a MultiMeter?

Only continuity, I'd say. One click of a 3pdt connects the middle row to the top row, another click connects the middle row to the bottom row.

Admittedly, I didn't even read the thread so this may not be what you are asking. 
I'm gonna go and read it now...

EDIT: I'm also at work but if you are certain you are using a common cathode bicolor, I'm not seeing why that setup wouldn't work...? Busted middle lug perhaps?

[Sibob]

Thanks, I'm now questioning whether it's a common cathode.  I had that in my head, however thinking back to when I was testing it last night, I think I had power to the middle leg and either of the outer legs to ground......which makes it common Anode?! I think I've had a brain-mush moment. 
How would the above wiring differ if it is common anode?

Cheers
Si

[muddyfox]

You'd just switch 9v and ground around. On your picture, 9V and CLR would go on the right (where there's ground now, middle led leg) and you would ground the middle (x)pdt lug (where there's 9V now).
Right now you are switching which led circuit gets the power and with what I wrote you'd be switching which circuit gets the ground.

[Sibob]

Thanks very much, appreciate your help. I'll be testing after my gig tonight and I'll report back!

Si

[Sibob]

All working, did turn out to be common anode. As soon as I swapped ground & 9v as you said, works perfectly

Thanks everyone for their input!

Si

[DutchMF]

To help in situations like this, I always check my LEDs with a DMM on the diode test setting. Put the red and black leads on the legs of the diode, if it lights up, the red lead is where 9V should go, and the black lead is where ground should go. If it doesn't light up, swap the black and red leads around. It should light up now, you're good to go! If it still doesn't light up it could be two things: a) your DMM is on the wrong setting, or b) LED is busted!

Paul