Making wah in sewing machine pedal?

[bancika]

Hi,
I'll probably get in possession sewing machine pedal I'd like to turn into optical wah ala Morley. Can someone give me more information about doing it, I saw some posts here (from oldrocker among others) but image links were dead. Which LED/LDR do I need, how to make light barrier that should move and (un)cover LED, how to make it switchless, any ideas at all are welcome
Tnx in advance

[oldrocker]

Well it really depends on what type of sewing machine pedal you have.  The mechanisms can vary a lot.  I also used the Colorsound Wah but other twin T wah circuits will work as well.  I used a 200k LDR I believe from RS.  Other values may work too.  My LED is yellow.  Experiment and see what works best.  Mine is spring loaded toe back so in this position the LDR is blocked by the lever.  As I push toe down the lever uncovers the LDR.  I put shrink tubing on the LED open on one end to direct the light beam so stray light doesn't effect the LDR in toe back position.  I put some pictures below to hopefully show you what I did in more detail.
http://www.logmonster.com/images/full/?pic=cswah_1162439148-422-14160.jpg
http://www.logmonster.com/images/full/?pic=Sewingped_1162536480-422-14165.jpg
http://www.logmonster.com/images/full/?pic=sew3_1170083831-422-14681.jpg
http://www.logmonster.com/images/full/?pic=sew2_1170098589-422-14680.jpg
http://www.logmonster.com/images/full/?pic=sew1_1170016758-422-14679.jpg
http://www.logmonster.com/images/full/?pic=d007d_1160300734-422-13888.jpg
http://www.logmonster.com/images/full/?pic=DS0010ns_1162432918-422-14161.jpg

[Paul Marossy]

Wow oldrocker, that's pretty impressive how you made all that work in there.  Pretty clever solution for the LDR thingie.

[oldrocker]

Thanks Paul,  It seems to work good although I'm sure not as nice as Wah experts like yourself would prefer.  I've been trying to get my Vox 847 wah to work the same way but the circuit just seems to difficult to convert.  Oh well I still have to track down another sewing machine pedal first.  I would like to redo the wire mounting inside the pedal and clean it up a little but other than that it's fine.  I brought it out the other day for my wifes brother to check out.  He laughed at first but after hearing me jam on it he thought it was a great idea for a wah mechanism.

[JonFrum]

I see sewing machines at the thrift store all the time. Last week I saw a pedal alone, so I'm sure they're out there for small money. I would have picked it up, but I'm not far enough along building pedals to get too tricky.

[oldrocker]

I have been checking around at thrift stores near where I live but they didn't have any yet.  You should pick it up next time you're there it's really pretty easy to do.  It's a lot easier than building an actual wah treadle mechanism but not as nice looking for sure.  As you can see by the schem.  the circuit I used is really pretty simple.
Sorry about linking the pics but for some reason I'm not able to post photos directly to the threads.  I'm sure why but they all stopped working one day.

[Paul Marossy]

Sorry about linking the pics but for some reason I'm not able to post photos directly to the threads.  I'm sure why but they all stopped working one day.

Probably bandwidth control...

[bancika]

Thanks guys, really appreciate it!
One thing I don't quite understand. Is your level moving up and down like you move your foot or back and forth, cause it seems like second one from pics. Second, Do you have enough gradual sweep cause it looks like it will block LED completely or uncover it completely very fast
And finally, how did you do bypass?
Thanks and sorry if I'm too curious
Cheers

[oldrocker]

Yes you're right that the lever does work that way.  Even though it uncovers the LDR quick and not gradually it has a fairly decent control sweep.  Keep in mind this is just the way I did it.  You might be able to come up with a more gradual actuator but I'm not sure how you'd do that with such a limited mechanism in most sewing machine pedal designs.  I suppose to get more sweep I could move the LDR to the other side of the lever and cut a very small horizontal V shape into the lever to get a more gradual control.  Hey, I just might do that. 
I didn't install the bypass yet.  Lack of room for it with the battery.  If I go with a PS the switch would be mounted  were the battery is and be actuated when the pedal is pushed all the way down.  So as you can see I'm still kind of working on it.  A DIYers work is never done.

[Paul Marossy]

My honest opinion is that the best use for an old sewing machine pedal is to use it for an unusual pedal enclosure or maybe for an amp footswitch. It's really hard to do a good wah in one of those things, IMO. Oldrocker did a fine job, however. 

[bancika]

Yes you're right that the lever does work that way.  Even though it uncovers the LDR quick and not gradually it has a fairly decent control sweep.  Keep in mind this is just the way I did it.  You might be able to come up with a more gradual actuator but I'm not sure how you'd do that with such a limited mechanism in most sewing machine pedal designs.  I suppose to get more sweep I could move the LDR to the other side of the lever and cut a very small horizontal V shape into the lever to get a more gradual control.  Hey, I just might do that. 
I didn't install the bypass yet.  Lack of room for it with the battery.  If I go with a PS the switch would be mounted  were the battery is and be actuated when the pedal is pushed all the way down.  So as you can see I'm still kind of working on it.  A DIYers work is never done.

yes, V lever shape is what I had in mind. It would be cool to come up with bypass mechanism that works when you put foot on pedal (even without pressing it) or something similar