# Whammy Style Pedal with Arachnid



## spindlebox (Apr 11, 2021)

I am trying to build a very simple pedal, using a volume pedal treadle that will go up and down 12 semitones; a member of my Guitar Pedal Builders group recommended the Arachnid with a modification.  I have a Roland expression pedal I'm not using and am thinking of putting the PCB in there.  This is what he said:

"Could use and FV-1 based "Arachnid" platform build from PedalPCB and acquire the different 'pitch' patches. Then add an express input jack to supplant one of the octave control pots. Or just rip out the guts of that expression pedal and build the Arachnid right into it with the treadle pot activating one of the 'Octave' controls.

Wondering if anyone has done anything like this with this particular PCB, and if you have any suggestions or mod schematics you could share?

Thanks in advance!!


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## DGWVI (Apr 11, 2021)

Here's a kinda crappy video showing the Pythagoras with Clock Module and Expression control of Pitch 1




I used the diagram from the wiki to add the expression input


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## Robert (Apr 11, 2021)

Pay attention to the sound quality in the video above when the pitch is shifted up.     

The FV-1 doesn't do "pristine" octave up, it will always have that slight vibrato effect caused by the two samples being crossfaded.... with that said it's most likely the best / closest thing to "Whammy" you'll find in a DIY project at the moment.


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## spindlebox (Apr 11, 2021)

Robert said:


> Pay attention to the sound quality in the video above when the pitch is shifted up.
> 
> The FV-1 doesn't do "pristine" octave up, it will always have that slight vibrato effect caused by the two samples being crossfaded.... with that said it's most likely the best / closest thing to "Whammy" you'll find in a DIY project at the moment.


That's great!!  That's better than what I'm experiencing now.  Do you have any recommendations on that particular mod?


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## spindlebox (Apr 11, 2021)

DGWVI said:


> Here's a kinda crappy video showing the Pythagoras with Clock Module and Expression control of Pitch 1
> 
> 
> 
> ...


Thank you for that!!  I'm new to this site do you have a link for the WIKI?


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## Robert (Apr 11, 2021)

Expression Control Wiring - PedalPCB Wiki
					






					wiki.pedalpcb.com


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## spindlebox (Apr 12, 2021)

Robert said:


> Pay attention to the sound quality in the video above when the pitch is shifted up.
> 
> The FV-1 doesn't do "pristine" octave up, it will always have that slight vibrato effect caused by the two samples being crossfaded.... with that said it's most likely the best / closest thing to "Whammy" you'll find in a DIY project at the moment.


I just noticed that is the Pythagoras?  Not the Arachnid?  

Also, it says it needs an EEPROM?  I looked at the build documentation and it doesn't appear to suggest any particular one.  I'm unfamiliar with these.  Is there a particular type I need to search for at Tayda for instance?


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## phi1 (Apr 12, 2021)

Pythagorus and arachnid are the same except for the # of patches (3 vs 8).

for several of the fv-1 builds here, all the code that makes the effect is stored in the eeprom chip. So the you can swap out the eeprom chip and get a whole new set of effects. The eeprom builder page has a whole list of the available patches you can load into an eeprom chip.


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## spindlebox (Apr 12, 2021)

phi1 said:


> Pythagorus and arachnid are the same except for the # of patches (3 vs 8).
> 
> for several of the fv-1 builds here, all the code that makes the effect is stored in the eeprom chip. So the you can swap out the eeprom chip and get a whole new set of effects. The eeprom builder page has a whole list of the available patches you can load into an eeprom chip.


thank you for your reply!  So I can get the EEPROM chip on Pedal PCB?


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## spindlebox (Apr 12, 2021)

Never mind!  I just saw the builder page.  WOW.  I had NO idea this was even a thing!!  Still pretty new to pedal building.  Mind blowing.  THANK YOU ALL!!!


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