two spst controlled remotely using single trs jack?

[jcpst]

I’ve thought about this a few ways. I would love any feedback if I write something incorrect.

Use a pair of optocouplers. The tip and ring could control two LEDs independently while sharing a common ground on the cathode side. Then the collector and emitter hooks up to where each spst is. But would I introduce resistance from the phototransistor side?

I also know you can use a transistor as a switch, but not sure how to implement that correctly either.

Or am I just trying to be a fancy pants and this would be easier as two ts jacks?

 

[jwin615]

I think it would be easier switching relays.
And I would put ground on the top so you make it impossible to scrape hot across the ground point, resulting in reversed polarity for a split second.
Fun fact, the patient alert system on most GE MRIs is wired with trs power and the tip is hot. The alarm is triggered when a patient squeezes a squeeze bulb and it actuates a air pressure switch. Well, sometimes they get wonky and the alarm won't stop beeping so the techs just unplug the trs plug to power them off and it almost always kills the unit. I've replaced sooo many because they wired the tip hot.

 

[Robert]

Agreed, I'd use relays unless this was some specialized case where an LDR / opto would work better.

If you're wanting to design a drop-in system that can be used in various circuits without any re-engineering, relays would be best.

 

[jwin615]

Also, may want to keep trs ground isolated to the relay circuit. Let the circuit it's controlling have a separate, isolated ground

 

[jcpst]

Thank you both for the responses.

This is for two mods, just to make/break a connection momentarily

So I could, for instance, use 2 of the Basic Relay DPDT Switches or Intelligent Modules

Looking at the PCB images, if I wanted an spst momentary footswitch in the enclosure and the ability to connect a remote switch, would I have to go with the intelligent one?

 

[Bricksnbeatles]

Looking at the PCB images, if I wanted an spst momentary footswitch in the enclosure and the ability to connect a remote switch, would I have to go with the intelligent one?

At the very least, you could use the non-intelligent one if both the pedal’s remote jack and the remote foot switch use isolated jacks so the sleeve connection isn’t grounded

 

[jcpst]

So now I’m thinking I already have one intelligent DPDT board, I can just get another. Then I have the option to do momentary or latching on each one, and I have another pole for an LED.