Tap Tempo Pedal Build for the GCP

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
sheldonheardmusic
Posts: 5
Joined: Thu Oct 31, 2019 1:14 pm

Re: Tap Tempo Pedal Build for the GCP

Post by sheldonheardmusic » Tue Jul 28, 2020 6:04 am

Hoping to add to this thread and maybe get a little light shedded on my issue. I'm trying to build a tap tempo for my Strymon Timeline that lives in a rack and this seemed to be an awesome solution... however with the latching switch I have the tap pedal on P2, set to my TL and sending a CC# 81 which is Strymons tap button. When I try and tap in a tempo the TL gets all confused and most of the time switches to LOOPER. Is this because its a latching switch? Any ideas?

phawinp
Posts: 1
Joined: Sat Mar 06, 2021 8:00 am

Re: Tap Tempo Pedal Build for the GCP

Post by phawinp » Sat Mar 06, 2021 9:54 am

I've managed to build a tap tempo switch using a SPST momentary switch and 2 resistors.
At first I tried debouncing the switch, didn't go well for me :lol:

It's basically a fixed expression pedal with no pot.

Here's the clip:
https://youtu.be/01PSXCqs13o

Here's the wiring diagram:
Image

Mess around with the resistors, start with R1 = R2 and then decrease or increase the R1 value until it gives you CC Value 64.
You do have to measure the resistor values.

** CC value 64 works for me, it might not work for your gear. **
*** If you have another expression pedal that you wanna use, be sure to plug it in to an EXP port.
It affects the CC value of the other port somehow. ***

I end up with R1=9.33 kOhm and R2=9.75 kOhm.
Theoretically, if R2=9.75 kOhm then I think R1 should be around 9.45 kOhm but this is the closest I have.

This works fine sending MIDI CC to my Atomic Amplifire (tap tempo, turning things on/off).
No switch bounce problem at all.

JohnClark
Posts: 7494
Joined: Tue May 05, 2009 2:33 pm
Location: The Lab

Re: Tap Tempo Pedal Build for the GCP

Post by JohnClark » Tue Mar 09, 2021 4:23 pm

phawinp wrote:
Sat Mar 06, 2021 9:54 am
I've managed to build a tap tempo switch using a SPST momentary switch and 2 resistors.
At first I tried debouncing the switch, didn't go well for me :lol:

It's basically a fixed expression pedal with no pot.

Here's the clip:
https://youtu.be/01PSXCqs13o

Here's the wiring diagram:
Image

Mess around with the resistors, start with R1 = R2 and then decrease or increase the R1 value until it gives you CC Value 64.
You do have to measure the resistor values.

** CC value 64 works for me, it might not work for your gear. **
*** If you have another expression pedal that you wanna use, be sure to plug it in to an EXP port.
It affects the CC value of the other port somehow. ***

I end up with R1=9.33 kOhm and R2=9.75 kOhm.
Theoretically, if R2=9.75 kOhm then I think R1 should be around 9.45 kOhm but this is the closest I have.

This works fine sending MIDI CC to my Atomic Amplifire (tap tempo, turning things on/off).
No switch bounce problem at all.
Great Idea!

Many MIDI devices do use any value between 0-63 and 64-127 as a toggle, and some will filter the bounce better than others. For instance, some devices won't attempt to respond again until the data value crosses the 63/64 threshold when the function is a sort of toggle like on/off or tap tempo. However some MIDI devices will count a Tap as ANY value seen making any attempt to de-bounce this setup an exercise in futility.
Glad you happened to be using a device that filters the data values!
------------------====Cheers!====------------------
Image
---------==Voodoo Lab Magician & Tech==---------

Johnny Luke
Posts: 1
Joined: Mon Jul 26, 2021 4:09 pm

Re: Tap Tempo Pedal Build for the GCP

Post by Johnny Luke » Mon Jul 26, 2021 4:42 pm

Hi guys, how are you? :)

Not to open another topic, I preferred to ask this one, since it talks about footswitch

I have a GCP and a GCX and use it to control a TC Gmajor 2, but I would like to use the GCP pedal inputs to have two more footswitches (I won't use any of the pedal inputs as tap tempo, I want to use them for turn effect blocks on and off, to change univibe speed, things like that ;) )

Now my question:

As John Clark said in some previous posts, GCP pedal inputs accept latch switches, would it work to use Boss FS6 to turn my Gmajor's effects on and off? :?:

I mention the Boss FS6 as an example because it has the option to choose whether the footswitch will work in latching or momentary besides having two footswitchs

If Boss FS6 doesn't work, what would be the best choice from well-known brands on the market?

I thank the friends who can take my doubts, the forum is fantastic :D

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