Lauriers Bypass Circuits

[jishnudg]

Having recently bought a bag of latching SPST footswitches, I was keen to try out the latching 4066+4049 examples here -

http://members.shaw.ca/roma/switching.html

However, I found an older entry in the forum, which talks of possible issues -

http://www.diystompboxes.com/smfforum/index.php?topic=38171.0;wap2

some of which (the pop at higher volumes) may/may not have been resolved. I'd like to redraw Lauriers circuit, incorporating all the improvements/mods that one may add to it, so we can have one more foolproof way of bypassing (pun intended) 3pdt footswitches....any help/comments on this?

Also, how can the circuit here - http://members.shaw.ca/roma/switching-2.html  be converted into one that uses a latching SPST?

Regards,
J.

[armdnrdy]

You have read through R.G.s Geofex on switching and the millennium bypass right?

Also, look up Wicked switches for 4066 bypass examples.

[duck_arse]

if you're building the circuit "bypass circuit using cd4016/4066 ( dpdt )", don't short pins 9-16 together, or to ground. you can pull the inputs high or low, doesn't matter, but leave the outputs unfettered.

as for the spst ..... not spdt at least?

[jishnudg]

@ duck_arse    -   Nope, they're these weird 'made in Japan' latching SPST switches...ought to work with the Laurier circuits,though, right?

@ armdnry   -    thanks for the Wicked Switches link!

[duck_arse]

they will work where he has a spst shown. I think they might be made workable in some of the momentary positions if a cap (integrator?) is added. I'd have to play with that to see if or not.

and down the bottom of the page, Laurier has also tied the output of a 4011 to V+, another no-no.

[armdnrdy]

I was working out the details of a frequency counter that Laurier has on his site, when I came across discrepancies between the schematic and the board layout.

I contacted Laurier, and he acknowledged that there was indeed a mistake with the schematic.
He replied that no one else had reported a problem with the build.

Bottom line:
There are mistakes on his circuits!
Proceed with caution! 

[jishnudg]

Thanks, armdnrdy ! I think I found what I'm looking for here http://www.thetonegod.com/tech/switches/Wicked_Switch_Toggle_NAND.gif   Really amazing article!

[jishnudg]

Here's a small layout for the same - - copied it from the layout in the Downloads section of TTGs site, but just added the DPDT switch.

https://drive.google.com/file/d/0BwMVia471c4SQ1NWV2tDZFRLeTg/edit?usp=sharing

[duck_arse]

http://www.thetonegod.com/tech/switches/Wicked_Switch_Toggle_NAND.gif =

403 Forbidden

Server configuration does not allow access to this page.

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so

I know he's a god and everything, but there's not a pin # to be seen on that page.

the switch on your excellent layout is only to indicate the working, yes? it is not actually wired, is it?

[armdnrdy]

I know he's a god and everything, but there's not a pin # to be seen on that page.

I would imagine the reason for no pin numbers is because it really doesn't matter which gate or switch you use or in which order.  (just like a quad op amp)

I believe the pin numbers for a design would be dictated by the layout. One would have to refer to the data sheet to keep things straight.

[jishnudg]

Yep it's just to show how this circuit produces the equivalent of a DPDT...

[The Tone God]

Hello,

Direct image link to the site is forbidden. You can link to the full page.

The switching elements can be moved with the reciprocating control input for layout convenience. That is why the pin numbers are not specified in the diagrams. Honestly the layouts were an after thought anyways. I added them to help people out.

I can't tell you how many times people have asked me about that Laurier circuits. I really wish he either updated or take down those layouts. Or atleast put up a warning. I have had people burn out ICs with his layout. Sigh.

I hope this helps.

Andrew

[duck_arse]

ahhh, for a minute there, I thought I was going to get a smite-ing. how come we can't link to the img, but we can post it? (or am I gonna get smote?)

[The Tone God]

ahhh, for a minute there, I thought I was going to get a smite-ing. how come we can't link to the img, but we can post it? (or am I gonna get smote?)

Its standard practice these days as it keeps people from leaching our bandwidth. It is still a better idea to link to the article because if there are any changes it would show up where as if we change the image it come up broken.

I save the smite button for other things like BS mojo claims.

Andrew

[jishnudg]

I'm sorry, Andrew  - - I'll keep that in mind - - thank you so much for these great switching circuits, though

[The Tone God]

I'm sorry, Andrew  - - I'll keep that in mind - - thank you so much for these great switching circuits, though

No need to apologize. All is good and I'm glad you enjoyed the article.

Andrew

[jishnudg]

Andrew, do you think you could, at some point in the future, expand on that article to talk about how we can use the same chips and principles to get 4PDTs, sequential switching etc?