Demedash Effects Incandenza Relay BypassVerified

From the post

Here is a contribution from Chris Stelloh that seem to be really useful. Chris says: This is an updated version of the Demedash Incandenza micro-controller free clickless relay true bypass switch. It takes up a bit more room than a simple 3pdt, but because of the friction-free operation of the SPST button, it will last WAY longer than that same traditional, mechanical 3pdt switch. I realize that most folks will not want to build an extra board where just a footswitch will do... but for those of us that DO, here's my drawing of a super-slick, silent, clickless relay that doesn't require any coding or microcontrollers. There are a few earlier versions of this circuit floating around the web, but this one has a very important update from Steve Demedash himself. The power filtering and 100 ohm resistor between the 555 and the relay is super important. I found that the power spike when engaging the flip flop was enough to mess with other circuitry that was close to the switch. For example: I had a dual circuit build with independent on/off switches and triggering one would sometimes trigger the other one unintentionally.

Anyway - here's a boring utility layout that has ended up being the thing I build the most, since I put these in just about any circuit that will permit it. This layout also allows you to omit the polarity protection diode for the main board and the status LED as well since those are both contained here on this switch daughterboard. The 5v DPDT relays you can use for this are not limited to just these three - however, these three are the smallest and most inexpensive I've found so far. Also - I don't like to use standing axial components or 3-row resistors but in the case of this board, I wanted to keep it as small as possible. Be sure and notice the anode of D3 connected to ground!