QUESTIONS? Call Our Gear Experts | 484-291-4327

Pedalbrainz Left Brain

Continue Shopping or Checkout



The Left Brain is a light-controlled expression pedal that interfaces with effects offering expression control.

Controllable patterns of light result in the virtual turning of knobs when used in-conjunction with the available properties of a compatible effect pedal.

Over 50 Modez of controllable expression, an expression pattern loop recorder, and a host of other features to harness the potention waiting in your effects pedals.


v2 - Arduino Upgrade - The Arduino QTPY replaces the Gemma M0 from v1 for even more creative computer controlled opportunities. With open-source software and full programmability, the Left Brain can be adopted and expanded to allow for any controllable patterns of light you can imagine.

v2 - LED Backlit Knobs - The Left Brain now features addressable LEDs behind each knob in v2. With light no longer confined to the inside of the enclosure, additional feedback can be provided about the different Modez through light. With the newly expanded Arduino capabilities there are now 5 total addressable LEDS (2 internal, 3 external) which can be configured to either modulate the expression or provide illumination through the knobs. Additional consideration has been made to allow for the scaling of the knob lights through software so you can choose how bright they are on the outside.


v2 - Buttons - Two buttons replace the complicated dance of knob turning from v1 and makes changing between new Modez and Banks of Modez easy. This also means the ability to create utility and special Modez.


v2 - Voltage Regulator - Leveraging standard 9v center-negative effect pedal power means stepping down to 5v to power the Arduino and LEDs in the Left Brain. While the voltage divider used in v1 worked great to power the Gemma M0, the addition of LEDs behind the knobs in v2 has increased the need for stable 5v power. The left brain now uses a 1117 5v Voltage Regulator that is surface mounted on the expression board.


v2 - Surface Mount Resistors - Each of the models in the Pedal Brainz Series can be easily adapted to provide different resistance to ensure maximum compatibility across the specifications of different effect pedals. This is achieved through a matrix of resistors that can be switched between (10k, 25k, 100k) in-conjunction with the scale knob, bringing flexibility and creativity. While the through hole resistors of v1 allowed for greater modding flexibility, v2 uses tiny surface mount resistors that make production faster.


3 Control Knobs:
Adjust the properties of light patterns and expression. (See Banks/ Modez below for property details)

2 Buttons:
Single-click to Increase or Decrease Mode number.
Double-click to Increase or Decrease Bank number.
***Bank change always begins with Mode 1 of new Bank***

Expression Type Switch (EXP / EYE):
Choose between manual expression (EXP) or engage the internal photocell (EYE) to add light-based control.

Scale Knob:
Variable control of the Maximum expression value.

Range Switch ( Least | / Less || / Full ||| ):
Adjusts the Maximum range of the Scale Knob.

Tip Direction (TR / RT):
Swaps the direction of expression between Tip-Ring (TR) and Ring-Tip (RT) for greater compatability across effects.

TRS 1/4" Jack:
Requires TRS (Tip, Ring, Sleeve) between Pedal Brain and effect.

DC Jack:
Tip Negative, Sleeve Positive.

USB-C Jack (Internal):
For accessing the internal Adafruit QTPY platform.

    Brand: Pedalbrainz


    More Great Gear