AMB Laboratories DIY Audio

[mcfrede]

I am currently adding bells and whistles to my Beta22 build and I was wondering if there is a way to get a standby indicator LED?
Basically, what I am trying to achieve is I want the Bulgin switch to light when the Sigma22 is in standby, and when I push it to turn on the Sigma22 (and Beta22) I would like the button LED to turn off and instead I will have a pattern of LED's on the front panel light up (that same pattern will also light up one the Beta22 so what I am trying to get is an aligned presentation of the units).
I guess I will have the most luck fiddling with the Epsilon24 if at all. Is there an "always-on" DC line that I can tap into or some other way involving only minor work and modifications?

[amb]

The ε24 is always powered, and has on onboard 7812 regulator.

[mcfrede]

Oh yeah, I got it that far, but how to make it turn off the LED when I turn on the Sigma22?

[amb]

Oh yeah, I got it that far, but how to make it turn off the LED when I turn on the Sigma22?

You'd have to invert the LED "logic" with extra circuitry.

[mcfrede]

Sorry to keep bothering you, but would you be kind and help me in the right direction?
Is there a normally closed relay I could use to break when I turn on the Sigma11 or should I go another way about it?

Sendt fra mobilen.

[linux-works]

you could use relays and those are the easiest and simplest. when the relay is clicked down, you would use the N.O. and common wires to have it *break* the circuit on those 2 contacts. that is one way to do an inverter.

[mcfrede]

you could use relays and those are the easiest and simplest. when the relay is clicked down, you would use the N.O. and common wires to have it *break* the circuit on those 2 contacts. that is one way to do an inverter.

I like easy and I like simple! Also, I like cheap, and having to buy a relay shouldn't stop the project. I might get back with a couple more questions about the wiring, but for now I will try to see if I can figure it out myself.

Thank you all for your help thus far!

[linux-works]

another simple idea: consider the led that has its minus lead tied to gnd. when you connect its plus lead to plus, it turns on. no surprise and as voltage goes 'high' the light goes on.

now, to invert it, simply swap the polarity of the led and tie its plus side to plus and leave it there. now, to turn the led on, touch its minus side to gnd. this is a form of inversion; you lowered the voltage to turn the led on.

meditate on that for a while and maybe there will be an 'aha! moment'

[mcfrede]

OK, I will play along.
From what you say, I should keep in mind that I can turn on the LED by placing my switch on either the + (plus) or - (minus) side.
This also means that I can turn off the LED by removing the connection to either + or -.
I reckon you want me to tie the LED + to the permanent 12V supply and start looking for a GND point that is "ON" in the Epsilon24's off state and "shut off" when the button is pressed.

[amb]

Don't connect the LED directly across the power supply and ground! You need the current limiting resistor.