PCB mounted foot switch

[ostelarsen]

Hello.

Does anyone have any experience with soldering a 3PDT foot switch directly on the PCB inside a stompbox? (and of cause mounting the switch on the chassis).

My worries are that the 'click' might do something to the soldering connections over time (but if not, it would be a lot easier in this particular design).

Best regards! 

[MikeH]

Sometimes (and this is rare- I've never had it happen to me but I've read others posts stating this) a circuit can have 'microphonic' properties, so-to-speak.  And when the pcb is touching the switch you can get audible noise, clicks and pops, when switching it on and off.  This is fixed by insulating the pcb from the switch with some foam, or mounting it on standoffs, not touching the switch.  I imagine if that can happen, then having the circuit soldered directly to the switch might do the same.  That being said, tons and tons of DIY and commercial pedals solder the switches directly to pcbs and mount them that way. So in all likelihood, you could do so without any problems.

[Taylor]

If the switch is the only part that is mounted directly to the box and the PCB, I see no issue, other than that the board will rotate when the stomp switch nut comes loose and the user attempts to tighten it.

However, usually when people do this, they also mount the jacks and sometimes the pots to the PCB. IMO this is bad practice. If everything is aligned perfectly on all axes, and if all nuts are secured precisely, then there will be no problem, but in the real world, people don't drill perfectly, and these parts are stressed so the mechanical mounting cannot be depended on forever. All of these forces will stress the PCB and crack traces.

If you're building this just for yourself, go for it. You'll be around to repair it when (not if) it breaks. But if you're building a bunch of these (sounds like it, could be wrong) I would strongly recommend you go another way. Plugging/unplugging jacks will crack traces. Stomping the switch will crack traces. 3PDTs will fail, just a matter of fact. When they do, it'll be a much bigger pain to fix if the board is mounted to the switch. Repairs are time-consuming, so you have to do a cost-benefit analysis: if the time saved by mounting them this way is overwhelmed by the extra cost and time of doing the repairs, it's a false economy.

If you're designing something that you're going to build a lot of, IMO mount things to the board which don't receive much stress under normal use (pots, toggles), wire jacks and stomps offboard, and design out the 3PDT.

[trjones1]

and design out the 3PDT.

Any suggestions on alternatives?  I've heard Alpha dpdt stomps are rugged, but are they significantly better than 3pdts?  Relays?  Electronic switching?  I know there are a ton of posts on this topic, but I'm always looking for new opinions.

[Hides-His-Eyes]

and design out the 3PDT.

Any suggestions on alternatives?  I've heard Alpha dpdt stomps are rugged, but are they significantly better than 3pdts?  Relays?  Electronic switching?  I know there are a ton of posts on this topic, but I'm always looking for new opinions.

The feel of alpha DPDTs is just so much nicer. No idea if they're more reliable.

Millenium, relay or CMOS switching.

[caress]

If the switch is the only part that is mounted directly to the box and the PCB, I see no issue, other than that the board will rotate when the stomp switch nut comes loose and the user attempts to tighten it.

However, usually when people do this, they also mount the jacks and sometimes the pots to the PCB. IMO this is bad practice. If everything is aligned perfectly on all axes, and if all nuts are secured precisely, then there will be no problem, but in the real world, people don't drill perfectly, and these parts are stressed so the mechanical mounting cannot be depended on forever. All of these forces will stress the PCB and crack traces.

If you're building this just for yourself, go for it. You'll be around to repair it when (not if) it breaks. But if you're building a bunch of these (sounds like it, could be wrong) I would strongly recommend you go another way. Plugging/unplugging jacks will crack traces. Stomping the switch will crack traces. 3PDTs will fail, just a matter of fact. When they do, it'll be a much bigger pain to fix if the board is mounted to the switch. Repairs are time-consuming, so you have to do a cost-benefit analysis: if the time saved by mounting them this way is overwhelmed by the extra cost and time of doing the repairs, it's a false economy.

If you're designing something that you're going to build a lot of, IMO mount things to the board which don't receive much stress under normal use (pots, toggles), wire jacks and stomps offboard, and design out the 3PDT.

very good advice.

[smallbearelec]

Since I sell a wide variety of switching solutions, I have no "religious" bias. I did want to point out that you can now do "bypass-on-board" with a 4PDT tactile switch:

http://www.smallbearelec.com/Detail.bok?no=1095

and actuator:

http://www.smallbearelec.com/Detail.bok?no=32

Some people implement this with DPDT + LED Driver circuit, also.

[Taylor]

Steve, I'd be interested to see a mini-tutorial or even just a photograph showing how the actuator and PCB switches mate up in that setup. I'm having trouble envisioning how the spring stays registered on the plunger of the switch.

[trixdropd]

Steve, I'd be interested to see a mini-tutorial or even just a photograph showing how the actuator and PCB switches mate up in that setup. I'm having trouble envisioning how the spring stays registered on the plunger of the switch.

The spring goes right over the switch button. pretty simple. I am gonna utilize this setup soon.

[armstrom]

Sorry to dig up an old thread, but I'm also curious how this system works. Does anything need to be placed between the actuator and the switch? How to you prevent overzealous stomping from breaking the PCB? I would assume some sort of squishy rubber material could be used to transfer the force from the actuator to the switch while preventing direct physical contact between the two. Also, how does the height of the 4PDT switch compare with the various PCB mounted pots sold at smallbear? My goal is to have everything mounted on the pcb to speed up assembly time but I'm not 100% sure I can pull it off without datasheets and/or mechanical drawings of the various components.  Are these available?

These are the various pots I'm considering but without a drawing for the switch and the actuator I can't be sure which one will provide the proper height (if any!)
http://www.smallbearelec.com/Detail.bok?no=692
http://www.smallbearelec.com/Detail.bok?no=710
http://www.smallbearelec.com/Detail.bok?no=1139

Alpha seem to be pretty tight-lipped about datasheet (I can't even find any reference to the smaller 9mm pots on the alpha web site!) so it's tough to do the research myself. I would really like to avoid having to order all the different types just to see what fits

Thanks in advance!
-Matt