Momentary hold soft switch

M

Morbidpale

Active member
I want to put a dpdt switch into a pedal with a soft switch. It only needs to he engaged while pushed in.

The relays i bought are for 4.5v but only engage with 5v. Go figure. So I stole 5v from the L7805>run to momentary switch>positive of coil. Also an led I may include but it's not needed.

It works. It can't be this easy right? Nothing is ever as easy as i think it should be. Please tell me what I dont know or confirm that for once it's just fine.

Drawing and relay sheet included.
 

Attachments

I'm not sure why (or how) to use a relay for this.


Looking at the delay's schematic...

I would just use a Momentary DPDT.

Run a wire from Lug1 of the REPEAT pot to Lug2 of the switch;
Run another wire from Lug1 of the TIME pot to Lug5 of the switch;
Switch-Lugs1&6 are wired to GND.

If I wanted to add an LED, just for fun, I'd use a Momentary 3DPT.
 
Thanks. I get how to do the normal 3pdt. The problem is the best ones I've found (ilovemyswitches) are still pretty stiff to engage.
So momentary/relay would be nicer. It does work i just wanted to know if I'm going to burn it out (x) latches from now without a diode/capacitor configuration somewhere or it really is this easy.
 
ICTRock said:
it seriously isn't any more complicated than using a DPDT momentary
Click to expand...

Yes, except my design can use the existing SPDT stomp switch, alleviating trying to find a 3PDT (my design can simultaneously actuate an LED indicator) with the right height throat to actuate the effect or true bypass. Plus, 3DPT typically require more downforce to actuate and are mechanically noisier.
 
andrewsrea said:
Yes, except my design can use the existing SPDT stomp switch, alleviating trying to find a 3PDT (my design can simultaneously actuate an LED indicator) with the right height throat to actuate the effect or true bypass. Plus, 3DPT typically require more downforce to actuate and are mechanically noisier.
Click to expand...

Very cool !

I see now how a Momentary-SPDT would work for this... LUG2>GND, the other lugs going to each POT's tab-1. Still no need for a relay and the SPDT should be easy enough to press, and if not...

2021_BFB_Slide_Mini_Colored_buttons BAREFOOTBUTTONS.png

So with the DPDT, you could have poleA work the switching and poleB activate the LED — or do you have a method of grounding the LED with the SPDT?
 
Feral Feline said:
So with the DPDT, you could have poleA work the switching and poleB activate the LED — or do you have a method of grounding the LED with the SPDT?
Click to expand...
I repurposed the stock SPDT of a Vox wah which has a very long thread neck to reach the treadle that no 3PDT that I could source could be found. The stock SPDT becomes in essence a SPST for grounding the relay coil and the LED indicator at teh same time. The common lug is sent to ground and the switched lug (pick one) is connected to the relay coil and LED cathode. I send the +5VDC (post 7805 regulator) to the relay and the LED via a 30 Ohm resistor, with the LED circuit in parallel with the relay coil.

The +9VDC goes to the stock wah circuit and also to the 7805 regulator for the switching.

The advantages of this relay-based true bypass design are:
- Improved reliability: You know the stock stomp switch will fit, work and be available when it wears out, versus buying a DPDT or 3PDT stomp
switch.
- Quiet switching: 3DPT stomp switches have three times the mechanical movement, take more pressure to actuate and are therefore,
louder. They also have true bypass pops, if you do not add strategically placed 1M resistors.
- Comparable cost: The cost of components (Terro board, 5VDC DPDT relay, resistors, LED, 22 gauge hook up wire, solder) is about the same as
the cost of a single 3PDT switch (less than $6).
- Indicator light: Wah's are notorious for remaining 'in-effect mode' when you think you've toed it off, then a quarter song later you realize it is
still engaged. The LED indicator helps verify that quicker.
- Comparable sourcing parts and build time: Some wahs can use easy to find DPDT or 3PDT stomp switches, but many cannot. I can build
(from scratch) and install this assembly in about 30 minutes (obviously your first time may likely have a learning curve and take longer). When
replacing the stock stomp switch with another, you sometimes need to make the hole bigger, often have to shim with washers and nuts to get
the height to actuate correct.


Enjoy!
 
That's awersum for the wah.

So for the OP's intended use in the delay, having to switch out GND for two pots (one has to be grounded while the other is not, according to the schematic posted) — you'd just use two relays:

RELAY1 connected to SW-LUG1
RELAY2 connected to SW-LUG3
GND connected via SW-LUG2 (common).


I've got some relay-switching in a couple of VFE-DIY builds, and maybe a couple others, and in addition have some PedalPCB RELAY-based switching PCBs (*as yet unbuilt) ...but really I've not plumbed the depths of DIY-RELAY at all yet.


The WAH solution seems like a no brainer to me. I'll have to source some of those VOX SPDT switches for my treadle-based projects.


For the OP's delay, given the schematic, I would forgo the LED and just use a momentary-SPDT, at least until I get more familiar/comfortable with relay-switching:

MR ECHO SPDT SLAM SWITCH.png
 
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