ninjaNIRS – A Wearable fNIRS System

ninjaNIRS is a modular and wearable fNIRS system that will ultimately support up to 128 optodes, each with a dual wavelength source and photo-diode detector. The system shown above has 8 of these combined source and detector optodes. The motivation, concept, components and initial performance characterization of the ninjaNIRS system are described in a poster we presented at SPIE Photonics West in 2019.

Early Adopters

As of October 2019, we are running our first studies with this system at Boston University. Contact David Boas at Boston University if you would like to be an early adopter of this ninjaNIRS system and provide feedback to us on its further development. We are able to give away the first several of these systems with 8 combined optodes, the control board, and the ninjaGUI acquisition software. To be considered, please send us a proposal that is less than 1 page and describes what initial measurements you will perform with the system, the paper it will lead to, the academic contribution that will be made by the paper, and the prior experience you have that raises confidence that you will succeed as an early adopter of this system.

Hardware Resources

Schematics are available for the optode main board, the optode connector board, and the control board. Contact Bernhard Zimmermann or David Boas at Boston University if you would like access to the circuit diagrams and firmware.

Optode packages: We have designed 3D printed housing for the optodes.  The optode circuit boards are packaged in nylon 3D printed. Optical waveguides are used to efficiently deliver the light from and into the optodes. The waveguide diameter is 3mm to optimize light throughput and minimize patient discomfort and ability to reach through the hair. A length of 3mm from the optode surface was chosen. We utilized 3mm core diameter plastic optical fiber that we manually polished to increase transmission efficiency.

ninjaCap: We design the placement of the optodes on the head cap using the atlasViewer software package. We then 3D print the cap with the optode holders in the design locations using the flexible 3D print material called ninjaFlex. Please contact David Boas if you would like to have your custom cap 3D printed.

Software Resources

The ninjaGUI data acquisition software is available on github here. It is designed to be flexible enough to operate different fNIRS systems. Presently, it is able to operate the TechEn CW6 system in addition to ninjaNIRS.

Contributors

  • Bernhard Zimmermann, Lead engineer of ninjaNIRS
  • Antonio Ortega Martinez, ninjaGUI software developer and designer of the optode packaging
  • Alexander von L├╝hmann, ninjaNIRS and ninjaCap developer
  • Nathan Perkins, ninjaCap developer
  • Cameron Snow, ninjaCap developer
  • David Boas, System designer

Archive

Our January 2017 prototype to test noise level and dynamic range is described here.