System Architecture

NinjaNIRS 2022 is the latest model of the ninjaNIRS set of systems and implements the capability of whole head fNIRS array coverage with high density optode placement and simultaneous EEG measurements. Optode count for the system has been increased to 56 sources and 144 detectors with 8 independent IMUs with a specialized source optode that can be directly mounted on an EEG electrode. This site provides all technical documents for the parts we have created for this system including a harness mounting system for subjects to wear the system preserving range of motion. All files necessary to reproduce this fNIRS device can be found on our GitHub but direct links to individual items in the system are provided in the sections below.

Control Unit Documentation

A new control unit has been developed to allow for an increased module count appropriate for whole-head, high-density fNIRS array coverage. The current firmware for the system now allows for up to 56 source, 144 detector, and 8 IMU modules using expansion cards connected to the control unit interface backplanes. Communication with the system can be done either directly using a USB connection to the researcher’s computer or wirelessly through an internally mounted Raspberry Pi Zero 2 module. All production documentation is included below.

Control Board: Schematic PDF, GitHub Folder

Source Backplane:

Detector Backplane:


Battery Box:


Optode and IMU Documentation

The ninjaNIRS 2022 system was designed to be compatible with both our own open source optode modules available for users to create themselves or with commercially available optode modules made for the NIRx NIRSport 2 imaging system. A specialized source module is also available that can be mounted on top of active wet electrodes for the LiveAmp 8/16/32/64 EEG system created by Brain Vision. All documents needed to recreate the open source optode modules are provided below.

Source Optodes


Interface Cards: GitHub Folder, Schematic PDF

Splitter Board: GitHub Folder, Schematic PDF

Detector Optodes


Interface Cards: GitHub Folder, Schematic PDF

Splitter Board: GitHub Folder, Schematic PDF


Splitter Board


This system was designed with the intention of allowing for experiments in a naturalistic environment including studies outside of a lab environment and to facilitate this, a harness has been created for subjects to wear the system in as unobstructive way as possible. This harness is a modified baby carrier purchased from Amazon and instructions on how to modify it for use as well as all materials purchased below. Due to the toughness of the materials used it is advised to use heavy duty needles on any sewing machine used to make the harness.

Harness Alteration Instructions PDF