Wah heel bypass Idea

[RobotZombie23]

I just finished putting together my Tear Jerker wah pedal. It sounds amazing!

I want to make a spring return bypass setup so when the spring pushes the heel all the way back it pushes a button to tell the PedalPCB Basic Relay Bypass (non-latching) to bypass the wah. And when the button is unpressed it engages the wah. Kinda like NickC's Tear Joker but without the extra switch. I was thinking of removing the 3pdt foot switch all together too.

Does this sound doable? Does anyone see any problems with trying this?

Using this as a normally closed button:

 

[jimilee]

Your ideas are spot on. I would use a spring like this https://a.co/d/hbIgX2h

 

[Feral Feline]

Looking forward to seeing your implementation.

Hoping I can beg/borrow/steal it, too.


I've always hated that (most) wahs' have to go high (toe down) to engage them; I've always felt they should be "neutral" when engaging and return to neutral when disengaging them.




Here's another idea:

Employ a Hall-effect sensor for the switch, that way there's nothing physical that can get bent/broken/damaged.

 

[Robert]

Employ a Hall-effect sensor for the switch, that way there's nothing physical that can get bent/broken/damaged.

Or use a dual-gang pot where the additional gang generates a threshold voltage to trigger the relay at toe-up.

You could theoretically trigger switching at any point in the sweep of the treadle.


I wonder if a Z**X "probe" style copper plate under the rubber tread would work? (Not for the actual sweep, just to detect a foot on the treadle)

 

[RobotZombie23]

Here's another idea:

Employ a Hall-effect sensor for the switch, that way there's nothing physical that can get bent/broken/damaged.

This lead me to find Reed Switches. I was racking my brain to find out how I was going to mount these mouse button switches because it looks like there's too much throw in the red buttons above. I guess I'll see what I can come up with between the 3 and send back what doesn't work. I like Robert's dual-gang and copper plate ideas too. I use a zprobe for my cnc but it's not obvious to me how to make that normally closed. I was going to wait for a sale (Valentines?)to get the Basic Relay board because there's other boards I got my eye on but I might just have to try this sooner rather than later.

 

[Robert]

I was going to wait for a sale (Valentines?)

There will be a second "Black Friday" sale this weekend since Canada missed out because of the strike.

 

[RobotZombie23]

I'm trying to figure out how to mount the Relay Bypass pcb inside the wah case. It would be nice if the pcb had a screw hole.
It's not ideal but what if I taped the bottom and hot glued or JB weld the pcb to the side of the enclosure?
Or something like this? a 3d printer would be handy to make something like that.
Any Ideas on how to accomplish this?

also after some testing it looks like a reed switch might just work through the enclosure. I'm going to put the magnet in the heel and have the switch inside the enclosure

 

[Robert]

Can you attach the bypass PCB to the wah PCB with rigid pinheaders?

 

[RobotZombie23]

Can you attach the bypass PCB to the wah PCB with rigid pinheaders?

no, stuff will be in the way

 

[RobotZombie23]

I should be getting my components for the Relay Bypass soon. I want to confirm my wiring is OK. I'm jumping r100 and the led and sending the power to the sw and gnd lugs then to the relay bypass. This seems cleaner than tapping the bottom of the board for power. I just want to be sure it won't fry anything.



also I got my reed switch working... for now, we'll see. It's kind finicky

 

[RobotZombie23]

Reed Switch testing

 

[RobotZombie23]

I got my Relay Bypass all soldered up. It doesn't seem to be working correctly. It seems to be acting as latching not non-latching. This is the relay I used. It says non-latching. But when I hooked it up to a regular momentary button. It should turn on when I push and hold the button and turn off when I let go right? Right now it turns on and stays on when I let go and turns off if I push the button again. What the hell?

 

[Bricksnbeatles]

I got my Relay Bypass all soldered up. It doesn't seem to be working correctly. It seems to be acting as latching not non-latching. This is the relay I used. It says non-latching. But when I hooked it up to a regular momentary button. It should turn on when I push and hold the button and turn off when I let go right? Right now it turns on and stays on when I let go and turns off if I push the button again. What the hell?

latching vs non-latching only refers to the type of relay in this case. Both the latching and non-latching relay bypass boards are functionally identical in terms of behavior— it’s just a matter of the relay used and the current draw (latching relays are more expensive, but the board only draws current when switching, Non-latching are a bit cheaper and the board draws constant current iirc).

@Robert is there a simple hack to the 555 section of the non-latching board to make it a momentary-on behavior? Technically, wouldn’t it be doable with just a 5v regulator and a momentary switch and not need any of the other parts if that’s all you’re trying to achieve?

 

[Stickman393]

Hmmm. As I was reading through this I suspected that this might be the case.

The non-latching nature of the relay references the fact that it will only stay in the non-normal condition for as long as the coil is energized.

A latching relay will switch positions and stay in that position until energized again.

That is to say: the PPCB relay boards require a new "rising edge" control signal in order to switch contact positions in the relay.

That means, basically, that you have to tap once to engage, and another time to disengage. Remember, these are made for stompboxes with normally open momentary switches.

You're using a normally open reed switch and activating the switch with a magnet, yeah? Basically, that means that you want the effect disengaged with the switch in the "on" position, and the effect engaged with the switch in the "off" position.

This is relatively easy to hack, honestly. You'd just need to route the relay coil voltage through the reed switch. Use the in/out jacks on your common terminals, use the normally open contacts as your "bypass", and use the normally closed contacts as your effect send/return.

This is going to be backwards from how the PPCB board works IIRC. I have a crybaby 105Q that uses a similar sort of setup, though it uses a short-throw tactile switch that is mounted directly to the board. It also has an adjustable time delay. Sort of a "delay on break" control that holds the effect in bypass until a specified time elapses.

Which...honestly, it may be a good idea to figure out some way to incorporate a slight time delay (milliseconds to nanoseconds). Just to prevent rapid-cycling of the relay coil and chattering the contacts. The 555 could probably handle this task.

There may be a simpler way of modifying the board, though. Robert may be able to provide some guidance for modifying it to "effect on" with the switch engaged and "effect off" with the switch disengaged.

 

[RobotZombie23]

That means, basically, that you have to tap once to engage, and another time to disengage.

It would have been nice if someone told me this on my original question.

 

[Stickman393]

It would have been nice if someone told me this on my original question.

I mean, sure, but these are technical questions, and folks don't always 100% catch all the ramifications of a specific application.

But now, you've learned something about how these things work. You tried something out, it didn't quite work, and now you know more. You're also on the path to finding a solution that *will* work.

That's part of the process. At least in this instance nothing is broken, it just isn't working the way you expected.

You're on the right path, and folks here aren't trying to mislead you. Had I seen this earlier I woulda said something, but alas, that's not the way it turned out.

So, ya know, chin up, guy.

 

[RobotZombie23]

You're using a normally open reed switch and activating the switch with a magnet, yeah?

no, I'm using a NC reed switch.

This is relatively easy to hack, honestly. You'd just need to route the relay coil voltage through the reed switch. Use the in/out jacks on your common terminals, use the normally open contacts as your "bypass", and use the normally closed contacts as your effect send/return.

please dumb this down for me. I get the routing the power through the switch but how would I route the bypass/effects?

 

[RobotZombie23]

I'm thinking I might be able to make it work the way I want If I remove and jump some components? Is it the 555 or the transistors? what does the latching? I can mess with it when I got time. I am really a noob at all this still. Learning as I go really

 

[Paul.Ruby]

This will all work but need an alternative programming of the ATtiny to use a latching switch instead of momentary switch. My code has this as an option if you want to try your hand at programming. I strongly suggest doing so because the ability to program opens up infinite possibilities...

My code and "getting started" info is on google drive:

PCB - Google Drive

drive.google.com

This is the build switch that will select the type of foot switch. Set this to "true" and the relay will just follow the reed switch position.


Also, one and only one target must be set "true." By default, it's set for the sparkfun programmer during code debug. When ready to program for the PedalPCB, change line 36 to "true" instead of line 33.

 

[RobotZombie23]

This will all work but need an alternative programming of the ATtiny to use a latching switch instead of momentary switch. My code has this as an option if you want to try your hand at programming. I strongly suggest doing so because the ability to program opens up infinite possibilities...

The ATtiny is a microchip? it's not part of this circuit. I was trying for a more simple solution. I'm not against coding. I've done some coding hacks in Linux. but I'd like to get what I have working

After staring at the schematic for the Basic Relay Bypass (Non-Latching) and the ne555 wiki for a while I'm still trying to figure out what holds the relay on. A flip/flop in the ne555? or the 78l09 is toggling high/low power to the ne555 when the button is pressed? Anyone care to explain the schematic to me?