Most of expression pedals are stereo (TRS). More information can be found here:
Arturia controllers and synths are using the same standard as Clavia (Nord), CME, Emu, Kurzweil, M Audio, Oberheim®, Roland with the pot cursor soldered on the jack tip, the top of pot connected to the plug Ring, and the bottom of pot connected to the plug Sleeve.
Here are potentially compatible pedals (indicative list):
At Arturia's we particularly use the M-Audio EX-P
Important note: On our side, we do recommend using pedals with a resistance value in between 10KΩ and 25KΩ.
For your information, the lower the resistance value is, the lower the efficiency range is (which may leave a deadzone at the end of the pedal). However, it will react in a more linear way.
- Pedals under 10KΩ would be better to prevent any potential difficulties to reach the maximum 127 value.
- 10KΩ pedals will be working fine.
- 25KΩ should also be a good compromise between linearity and efficiency range.
We would also recommend avoiding using pedals over 25KΩ, such as the Yamaha FC-7 (50K +/- 30%), which will exceed these recommended values. It would be possible to reach the maximum 127 value, but only on a small section of the pedal.
Make sure to refer to your pedal's User Manual to find these specifications.