Customized PCB – LARCH

LARCH was one of the first installations I created, designed to explore the boundaries of composition and scale. However, early on, we identified limitations in the system’s technical capabilities, particularly within the master cabinet that controlled the entire installation. This cabinet’s limited output became a bottleneck, prompting us to rethink the design.

To overcome this, we embarked on an intensive process of brainstorming and sketching, ultimately leading to the development of a custom-built PCB (Printed Circuit Board) tailored specifically for LARCH.

The design process required careful consideration of several factors. The existing aesthetic design of LARCH had to remain intact, and the technical components needed to be as compact as possible to be seamlessly integrated into the wooden blocks that form the installation.

The resulting PCB, developed alongside custom code, preserves and enhances the randomness central to LARCH’s functionality. This 12V circuit, using a 5-pin DMX protocol, not only powers the LEDs but also communicates with them. The PCB executes pre-programmed instructions, ensuring an organic and dynamic interplay of light and sequence.

The system operates through a randomized process: all PCBs within the circuit are assigned random time intervals. The PCB with the shortest interval activates first, selecting a storyline from its program library. It becomes the “leader” of the circuit, playing the selected sequence, while all other PCBs synchronize and follow. Once the program concludes, all PCBs reset, and the cycle repeats.

This custom solution ensures that LARCH maintains its characteristic unpredictability while operating with precision and efficiency.

LARCH Electronics: Powering Creativity with Precision

At the core of LARCH’s electronics is the ch32x035, a modern 32-bit RISC-V MCU running at 48MHz/5V, similar in functionality to an Arduino. This advanced microcontroller efficiently controls WS2812 LEDs through timer-DMA and simultaneously manages DMX communication via UART-interrupt.

One of the standout features of this MCU is its ability to operate on 5V, unlike most modern 32-bit microcontrollers, which are limited to 3.3V. This makes it ideal for interfacing with hardware such as NeoPixels, DMX transceivers, and MIDI devices, without requiring level shifters or additional voltage rails.

The software is written in C, utilising the manufacturer’s hardware abstraction layer (noneOS) for optimal performance. While the MCU itself cannot generate true random numbers, it cleverly simulates randomness by seeding its unique identifier alongside a read from an ADC line. This ensures that the LARCH units “communicate” in a way that appears genuinely random, creating a captivating and dynamic interplay when the installations “speak” to each other.