Levinson Keyboard - 40% Split Ortholinear (Let's Split) - PCB Kit

The Levinson an improved version Let's Split and adds LED backlight and 2u key support. Supports MX/Alps/Choc switches.

There are two different types of Levinson PCBs currently available:

• Levinson Rev. 3 PCB Kit (this item): More DIY involved, where you have to solder on diodes/resistors/Pro Micro yourself
• Nyquist/Levinson Rev. 3 (see Nyquist product page): Less DIY involved. Already has everything except switches soldered to it. Bottom row can be broken off to convert the Nyquist to a Levinson layout.

The PCB Kit for Rev. 3 includes the following:

• 2 Levinson PCBs (1 left half, 1 right half)
• 2 Push buttons for reset
• 2 TRRS jacks
• 48 1N4148 through-hole diodes
• 2 4.7kΩ resistors for I2C
• 2 MOSFETS and resistors for LED support

Layout

Each half of the board is a 4x6 matrix, but there is the option to have a 2u key in the innermost corners in place of 2 1u keys. The spot for the 2u has holes for Cherry PCB mounted stabilizers. This layout needs 48 keycaps.

The Name

Continuing the theme of prominent people in signal processing and digital communications, the board is called the Levinson, after the Levinson-Durbin recursion algorithm. There also happens to be the Split Levinson recursion as well, which fits nicely into the world of split keyboards.

Firmware

The Levinson uses QMK for its firmware, and the code for it has been merged into the main codebase. You can find it here: QMK - Levinson directory.

Case

Cases and plates can be purchase here: Levinson/Let's Split Plates and Cases.

The case files for a sandwich-style case are still under development.

The kerf setting was set to 0.15mm for use with Lasergist and Ponoko.

Items needed for build

• 24 Diodes per PCB (through-hole (included with this item) and SMD diodes supported)
• 2 Arduino Pro Micro or Elite-C (you can mix and match)
• 2 Push buttons (included with this item)
• Optional - 2 4.7kΩ resistors if using I2C
• Switches - Alps or MX-compatible
• Case/Plates
• 2 TRRS Jacks (included with this item)
• TRRS cable
• Micro USB cable
• Optional - 2u PCB mount MX stabilizer if using 2u keys
• Optional - LED support components (included with this item)
• 2 AO3416 MOSFETs
• 2 4.7kΩ resistors
• Optional - LEDs and 470Ω resistors

Build Guide: Levinson Rev. 3 Build Guide

Default Keymapping:

The default keymapping that the board is pre-programmed with can be found here: Default Keymaps