Transforming the Keychron x Logitech Q1 RGB Wireless Keyboard: A Journey to Improve Battery Supply and Wireless Signals

The Transformation Journey of the Keychron Q1: From Single-Mode to Three-Mode Keyboard"

When the Keychron Q1 was initially launched in China, plans were underway to transform it into a three-mode keyboard model by adding the Youlian module. However, the limited space in the Q1's bottom case posed a challenge in accommodating a battery for power supply and also lacked an outlet for wireless signals. Consequently, the renovation plan had to be put on hold temporarily.

Inspiration struck when I came across station B's mid-frame transformation plan for the Q1. Intrigued, I purchased a set of middle frames for research purposes. The transformation yielded promising results, with improved quality and an unaffected appearance. Not only did this solution allow for the addition of a battery beneath the bottom case, but it also resolved the wireless signal issue. Coincidentally, while studying the Logitech G913 solution, I decided to incorporate it into the Q1 transformation project.

The middle frame was a mere 2mm thick, resolving resonance and leakage issues between the upper and lower shells. It offered over a day of RGB usage and demanded a battery capacity greater than 1500mAh. Ultimately, a 3mm thick battery with a capacity of 2500mAh was selected. This necessitated the middle frame to be at least 4mm thick, with the PCB requiring a 3mm raise.

Once the middle frame was assembled using an acrylic solution, the bottom light function could also be added simultaneously. To achieve a translucent effect, a sandblasting process was used on the side of the cutting edge. After fitting the PCB at the bottom and placing the battery, there was ample room for movement within the positioning board, successfully completing the middle frame transformation.

Simultaneously, the PCB transformation proved to be a challenging endeavor. Logitech G913 and TKL keyboards boasted numerous independent buttons and indicators, while the original main control board of the Q1 was too large to accommodate the PCB. After careful consideration, I decided on a transformation based on the G913 without the Fn function. This allowed for more flexibility in key development, facilitating the transplantation of the main control.

The G913 main control employed the nRF52840 solution, a powerful single-chip that met the requirements for three modes. However, it utilized aQFN pads, featuring a total of 73 pins in a compact 7 * 7mm size. Logitech utilized all pins, which necessitated routing the inner layer pins on a 4-layer board with 3/3mil wiring to meet PCB production and SMT processes.

By creating a 4-layer main control board and reserving only the core functions, all other circuit parts were shifted to the larger board to ensure a sufficiently small main control board. After investing countless hours, the main control board was finally completed, measuring 16.8 * 14mm—perfectly fitting the gap between the four buttons on the right and the arrow keys.

Keeping all functions and indicators intact presented a challenge during the scheme modification process. The G913 featured independent buttons and indicators for various functions such as M1-M3/MR (onboard configurations), 2.4G/BT/Game/Light control, etc. After several rounds of modification, the addition of an independent Fn key enabled the retention of all functions and indicators.

The key scheme reserved all function buttons except for playback control, which could be customized through the G key. The indicator light scheme implemented the Fn layering logic, enabling the RGB light to switch to a function indicator light upon pressing Fn. The knob scheme matched the Q1, serving as volume +/- function keys with a press-to-mute feature, multiplexed with position and Insert. Moreover, the power scheme employed ultra-low power chip solutions, ensuring efficient power saving and supporting 5V, 1.5A charging.

The RGB scheme made lighting adjustments to ensure the desired effect. The four buttons on the right side of the Q1 used the light positions of the last track/Num Lock/7/4 on the G913. With some tricks, optimal dynamic effects could be achieved. Additionally, ten RGB bottom lights were added on the left and right sides of the keyboard.

Switching relied on the original Mac/Win configuration toggle switch of the Q1, with Win representing On and Mac representing Off. A new USB small board was redesigned, fixing bugs from the previous Q1 small board and utilizing the FPC snap-on cable for easier installation. Moreover, the USB input featured ESD protection, while power supply protection relied on TI's power management chip, providing anti-reverse, short circuit, and battery overheat protection.

Completing the PCB layout, manufacturing the board, and conducting tests took an extensive amount of time, culminating in the testing of lighting effects, function tests, power consumption tests, and signal tests. Throughout these tests, the Q1 transformation showcased performance similar to that of the G913, with a significantly improved battery life due to the larger battery capacity.

The signal test utilized an IPEX4 PCB antenna with a gain of 5dBi, positioned in the upper right corner of the keyboard. In an environment with significant wireless interference, the Q1 performed admirably, remaining connected for two consecutive days without any disruptions. Further adjustments to the RF are expected to enhance the signal performance.

Despite the v0.1 version of the transformation having some logical errors, such as incorrect connections for the Game mode and battery indicator pins, and the knob orientation, the overall finished product is highly satisfying. The aluminum alloy/Gasket/full key without punching/RGB/hot-swappable/wireless three-mode keyboard meets all expectations in terms of appearance and functionality. It is worth noting that the Keychron Q1 embodies the essence of a high-specification, mass-produced keyboard.

The v0.1 version's issues will be resolved in the upcoming v0.2 version, which will introduce new functions such as additional bottom lights and button customization. As the transformation journey continues, the Keychron Q1 evolves into a versatile and high-performance keyboard that caters to discerning users seeking an exceptional typing experience.