The Adam-EEG GitHub Repository hosts India’s first open-hardware 32-channel EEG and biopotential acquisition board.

Originally designed from scratch in 2015 by Soul Scientific, the repository provides a low-cost, open-source alternative to highly restrictive research-grade neuroimaging and Brain-Computer Interface (BCI) hardware. It is officially licensed under the permissive Apache License 2.0, giving developers the absolute freedom to build, modify, and even commercially distribute the hardware architecture.

Architectural Breakdown

• At the heart of the project is a multi-chip, parallel acquisition strategy engineered to deliver high performance without taking shortcuts on the overall channel density.
• The Analog Front End (AFE): The board integrates four Texas Instruments ADS1299 chips. The ADS1299 is an industry-standard, 24-bit, 8-channel simultaneous-sampling analog front end specifically optimized for biopotential measurements. By pooling four of these ICs together, the board handles 32 truly simultaneous EEG streams.
• Daisy-Chain SPI Routing: To capture all 32 channels without timing discrepancies or excessive trace clutter, the four front-end chips are daisy-chained across a single Serial Peripheral Interface (SPI) bus. This approach maintains synchronous sampling without needing a multiplexer (muxing) system that could inject latency or degrade signal integrity.
• Dual-Microcontroller Layout: The core engine is controlled by a dual-ATmega328 processing scheme. Splitting the workload across two microcontrollers helps balance computational overhead while managing high-throughput data streams efficiently.

Fully Untethered Standalone Logging

A defining feature documented in the repository is its capability for fully standalone, untethered operation. The board features integrated onboard microSD card logging. Because the microcontrollers write raw high-resolution biopotential data directly to local flash storage, researchers and hardware hackers can record data without keeping the board tethered to a host PC. This removes a significant constraint for ambulatory BCI prototypes or dynamic motion monitoring experiments.

What is Inside the Repository?

• The project source is highly accessible, keeping its primary hardware CAD assets fully transparent:
• CAD Source Files: The repository includes EEG_64_1.zip, containing the full original schematic (EEG_64.sch) and the detailed physical board layout (EEG_64_1.brd) designed in EAGLE 6.6.
• The ARM Sibling: For engineers looking for modern processing architectures, the creator's profile also links to a parallel repository, Altiumeeg. This variation keeps the identical 4× ADS1299 topology but upgrades the system to a single Atmel ATSAM3U4EA-AU (ARM Cortex-M3) controller laid out in Altium Designer.

Crucial Safety Notice

• Because this is an unshielded prototype design rather than a clinical medical instrument, the repository explicitly specifies strict guardrails. The board is intended exclusively for prototyping and research; it lacks official FDA/CE regulatory clearances or formal patient-isolation certification. Anyone fabricating the board is instructed to power the device solely using isolated, battery-backed supplies—never hook up a live subject to a machine connected to AC mains power.