Hacking the Organelle to work with expression pedal + feature request

Hi all,

Just bought an Organelle and was really excited to get cracking with it. I also bought this expression pedal http://www.m-audio.com/products/view/ex-p (cos it was the cheapest and i’m cheap) but found that it wouldn’t trigger any patches which used the footswitch input. I connected a monitor, mouse and keyboard so i could view the values generated on the Organelle. I found that r exp was receiving values between 0.050 and 0.555 which i don’t believe is enough to trigger the 1/0 toggle of r fs which is used in quite a few patches instead of aux. I didn’t really want to have to hack every patch i load on to work with my pedal so i decided to mod mother.pd and place it in the patches folder on the usb to override the one on the Organelle. Here’s what i did in case it’s useful for someone else.

How i fixed it

Firstly i took a backup of root/mother.pd so i could roll back any changes.

In mother.pd/messageIO/pd analog subpatch, i took the raw input from the device, multiplied it by 2 (you might have to experiment with this value and your pedal), subtracted to allow the values to get down to 0 then clipped the range to be between 0 and 1 and sent these values to s exp. I used an expr object to send either a 1 or 0 if the value from expr goes above / below 0.2 (again this is to taste, you can set the threshold to a value of your choice) and sent this to s fs.

In mother.pd/messageIO/pd footswitch i removed the connection to s fs as i’m sending this information from the other patch.

I now get the full range of 0 to 1 from r exp and a 1/0 from r fs.

Feature request

I don’t know about how the Organelle receives and process osc data so this may not be possible but could there be a footswitch calibration patch which essentially sends a value from one of the knobs to a multiplication box which processes the footswitch input values and displays those values to screen (0-1 and 1/0 so you can see they are working)?

This looks great, thanks for sharing! The foot pedal stuff is a pain cause there are so many varieties…

The only thing I would recommend is a [change] object between [expr if ($f1 > 0.2, 1, 0)] and [s fs]. The exp value is a continuous value, so this will prevent sending redundant 0s or 1s. You really only want a single 0 or 1 when the foot switch changes.

For the calibration patch I think you could implement this already. The patch could send a calibration value to the custom mother.pd. When you get the right value, hit the button and it saves this value in a file (in the Patches folder with mother.pd). mother.pd loads this file on startup. kinda cumbersome but possible… I was thinking of a similar approach to change the default MIDI channel number.

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Thanks for the tips, I’ll have a play about with the patch this weekend

How did this play out? I can’t get my expression pedal (bespeco vm18l) to work with the organelle only getting ouputs between .4 and .6 rather than 0 and 1, wondering if there is a list somewhere of compatible pedals or if this can be easily fixed in the mother patch.
edit: Okay, so I have tinkered with it in the way suggested above - albeit not really knowing what i was doing.
I tested it with h Rando, using it to switch the activate the additional sequencer loops - which is working well.
I needed to enter different values in my boxes as - they are as follows:

It works fine for h Rando and a couple others, but for some other patches such as granular freezer - it skips the freeze function on and off while its in its ‘1’ position. Any ideas why this might be @oweno?

@Wannop try @oweno suggestion

Sounds like is still toggling fs because it’s getting a constant stream of input

D’oh! Thanks - I will try that.