Flip "on" status of LED?

[PRR]

> Why not go for a latching relay?

I think it "is" a latching relay? Bi-polar, not two-coil. It is only driven by a capacitor, no DC. Or am I reading wrong?

I _DO_ agree with adopting an already-made plan rather than forging your own path through the jungle. (Especially when offered for easy adoption, as R.G. has done.) "Inventing" can be fun and educational, sure. But don't burn a PCB until after the whole process of verification, including breadboard (even the dubious bits like those grounded outputs) and possible bench-racing on forums. R.G.'s plan uses a different relay but has been peer-reviewed for years.

[amz-fx]

> Why not go for a latching relay?

I think it "is" a latching relay? Bi-polar, not two-coil. It is only driven by a capacitor, no DC. Or am I reading wrong?

Yes, latching... here is a brief description of the basic idea:

https://www.electroschematics.com/6546/low-current-relay/

Best regards, Jack

[Rixen]

1 x low power 5v regulator
2 x power supply decoupling caps
1 x 8 pin ATtiny micro
2 x schottky flyback protection diodes

+ your existing LED, dropper resistor and (now 5V ) relay

selection of relay for a coil current <20mA.

works out around half the parts count, and lots less pins/nodes.

Bonus= ability to switch between momentary and latching operation if you choose to add that.

[lars-musik]

works out around half the parts count, and lots less pins/nodes.

Hey Rixen,

I'd be interested in your solution, the one I had a closer look at was this:

https://www.coda-effects.com/2016/04/relay-bypass-conception-and-relay.html

and I must say it seems like a fine piece of art but for my personal use a little over the top.

So if you have a reay-to-go solution with the above low parts count without drawbacks I'd gladly take it.

[Rixen]

the design I have is for two relays to enable multiple switching modes of two effects loops from one momentary switch input. ie press once for loop A, second time for loop B, third time back to bypass... another mode is press once to latch loop A, pressing again momentarily engages loop B as well (think volume boost), and a short tap sets it back to bypass

The principles will be the same, give me a moment to find and post the schematic...

[Rixen]

..and schematic for one with two relays, two loops. Note that the switch input signal is a hall effect sensor, but a mechanical contact would work too.. some reason it has been cut off the image LHS. Just pulls PB2 low. R1/R2 set the mode by analogue volatge on PA2. Ignore the red lines.

a single relay version would be much simpler (and the code also).

I came up with this because people kept asking if I could do a dual pedal enclosure- sadly not without investing $100k for additional diecast tooling. I haven't quite got to bringing the option to market (work & life can get busy) and the fact that I've already got an improved non mechanical yet true bypass design using photorelays on the cards...