driver circuit for two latching relays?

[arjepsen]

Hey.
I'm about to build an amp, in which I'll be able to switch channels using a latching relay - both from a momentary switch on the front, and from a pedal (also momentary switch).
(I want to use the single coil latching relays that stay in place after power is turned off).
I found a nice driver circuit for it, that works off of the 5V winding of the power trafo. So far so good.


However, I realized I want to be able to switch something else too, so I need another relay. As for the pedal, that just means putting another momentary switch in there - no prob...
But I would hate to have to run two jack cables from the amp to that one pedal...


Anyone have a good suggestion for a circuit that can control both relays, but could be done using a simple stereo jack cable???


Regards
Anders

[shooter]

I want to be able to switch something else too

independent of the 1st thing, or at the same time?

[arjepsen]

independantly.
Here's a schematic of the amp, and the driver circuit I found for just one relay.
I'd like to be able to switch the gain shape through a foot switch also, but would reeeally like to only use one cable...


https://www.dropbox.com/s/yiaovf24a9xfqql/Suburbia%20v03.pdf?dl=0

[sluckey]

4 conductor cable is very common.

Any info on the latching relay. Does the relay mechanically latch or does it use a set of holding contacts to electrically latch?

[arjepsen]

You're right. I guess I could use a regular rj45 cable and connector.
But somehow I feel jack cables are more.... rugged... I just like them better.... :-)


The relay is Panasonic tq-2-l 5v

[PRR]

If it is an amplifier, why use latching relays at all?

Use latching switches (plain Fender footpedal) to work non-latching relays.

[arjepsen]

yeah, call me silly, but I have a few of these lying around, and feel a sudden surge of love for them.... or maybe just want to learn a bit more ;-)

[arjepsen]

Would this work?

[shooter]

It was a bad day at the beerbaitngas, sooooooo, I already got a good start  ;
it hurts my brain, but I think it'll float, I have like 40lbs of 'ol relays as an anchor, in case it does 

[arjepsen]

well... it doesnt. Breadboarded it, and it's not working.
Still trying to get my head around the original circuit....

[nandrewjackson]

Look into the uln2803 relay driver chip. It uses small signal input control signals to turn on/off relays, small motors, etc on it's output channels. This could help simplify your switching, and would be more easily expandable, i.e. less components than all of those transistors you're building up .


I've got a new build I'm using them in, to turn on/off LDRs (light dependent resistors. )

[nandrewjackson]

One chip can drive 8 separate relays

[nandrewjackson]

The uln2803 relay driver chip output follows its input, so if you use momentary foot switches, youll need a latching chip inbetween your footswitches and the uln2803 relay driver chip. Thatll be an "octal d-type latch chip".




My new circuit will be using 4 octal latch chips running to 3 uln2803 relay driver chips to control 19 separate LDRs in various combinations.