Optoisolator as speaker switchboard?
Ragtop
Posts: 406
I have one audio source (amp 8ohm) that I want to select which speakers are playing. I was hoping to use a 4 channel Optoisolator but not sure if the strange results I am getting are because it is not made for doing that or maybe my wiring.
I have each speakers common wire coming to the Optoisolator and then to ground, hoping to complete the circuit of only the speaker I want. Not sure if it matters if the speaker wire goes to the emitter or collector. the other one goes to ground.
I have a spin program that sets each prop pin to 1 in sequence (turning others off) as I press a button. This part works lighting LEDs with and without the optoisolator.
I just have two speakers going now, I have one emitter/collector pair that always stays connected and another that just pops.
Am I using the wrong tool for the job or something else?
I have each speakers common wire coming to the Optoisolator and then to ground, hoping to complete the circuit of only the speaker I want. Not sure if it matters if the speaker wire goes to the emitter or collector. the other one goes to ground.
I have a spin program that sets each prop pin to 1 in sequence (turning others off) as I press a button. This part works lighting LEDs with and without the optoisolator.
I just have two speakers going now, I have one emitter/collector pair that always stays connected and another that just pops.
Am I using the wrong tool for the job or something else?
Comments
Most assuredly, yes. You'd be much better off using dry-contact relays. An optoisolator is nowhere near capable of handling the power output required for driving speakers.
-Phil
-Phil
Even without the question of momentary hi-z at the output, the make-before-break switches/relays helps to eliminate loud pops on the switch turnovers, which (when the speaker is driven high enough) can damage the speaker.
-- Gordon
And mercury-wetted relays, which nevertheless are fairly rare now, except in dusty surplus stores.
-- Gordon
-Phil
Brand spakin' new Hg relays used every day at where I work. Hundreds of instrument cards sold that have them.
They're "sitll alive and well" as Johnny used to say.
Nice to hear someone besides me advocating their usage!
And "they ain't nuttin" wrong with dusty old surplus stores. You can get some fine parts and ideas from wandering through such goldmines!
The coil voltage rating should be one of the voltages you have available or can add such as 3.3V, 5V, or 12V.
The current and voltage rating of the contacts needs to be high enough to handle the current and voltage going to the speaker. This will depend on the power output of your amplifier.
It is a plug-in amp that is 35 watts. Been searching for amps, but all I know is the fuse is 2amps. Does that mean the speaker wire can carry 17.5 volts?
Ragtop: Don't tell me this is the same part you wanted to use, if so, we all owe you an apology! It's still not suitable for driving speakers, but it's a very unusual part that fits your description!
That's a photocell on one end with a lamp or LED on the other.
It's used for feedback [e.g. AGC] not "port over".
I think we may actually have more surplus stores in the San Diego area than you do in LA, Erco. Wasn't it you who single-handedly put the Industrial Liquidators in Lawndale out of business with your constant haggling??! (No, not really. After Earl died his son folded back the biz. His son's son-in-law is running the store in San Diego.)
Phil, While it would have been a distance from where you are in the penninsula, the Boeing store was one of the best in the world. I'm sure you've been there, so you know what I mean. I still shed a tear at its closing. I visited a few times when I lived (for a very short period in the late 70s) in the Magnolia area of Seattle. Super amazing.
-- Gordon
When I posted, I was actually thinking of Torrance Electronics. A gem of a store with many parts old & new. Many faded plastic bins and worn cardboard boxes chock full of dusty treasures. Highly recommended, and they discount for cash!
When I first moved out here from the Midwest, I visited Boeing Surplus almost monthly. (That was when there were no stoplights between here and the Winslow ferry, and I could get to Seattle in an hour and a half.) What a sm
Ah, haven't been there in years. Forgot about 'em, in fact. Thanks for the reminder. I'll have to drop by the next time I have money -- which means not for a while!
I think this makes LA at least one-up. The combination of TE in Torrance, All in Van Nuys -- and if you're willing to risk the neghborhood -- Apex in San Fernando, well...that's a hard trio to beat.
(Also, wasn't a real fire station in Torrance the filming location for "Station 51" in the old Emergency TV show? Or maybe it Carson. )
-- Gordon
*My* ideal surplus has electronic junk, but also plenty of hardware. I buy nuts and screws by the pound, 20-30 pound minimum. I still walk away only spending <$100. I love it. For at least the San Diego surplus outfits, the prices are thanks to Uncle Sam, and his penchant for buying stuff he doesn't need.
-- Gordon