During the past year, several people have started to create modifications of the Ultracortex design to adapt it to their needs. Features like Cameras, Pupil trackers, and headphones are needed for those projects, and would ideally be integrated into a custom design. To help facilitate this we’ve created a system of accessory mounting points for the new M4. Now, to add functionality, we offer a specially designed CAD template containing the frame curves, mounting points, and construction planes. Aside from being much easier to modify than the model of the full frame, this also allows a modular approach so the headset can be adapted without re-printing the whole headset, reducing labor and shortening time between design iterations.
The reason we’ve put the time into developing this is because OpenBCI has received requests for CAD files (solid models) of the Ultracortex in addition to the printable STLs. While we plan to make all development files available, the design was created in several pieces of software and merged together for printing, so no single “source file” exists for the entire headset. The accessory templates and other essential files are being packaged into an M4 “Dev Kit”, which will contain all the most essential files for creating new versions and accessories.
The mounting system consists of eight clusters of mounting points that are integrated into the frame. Accessories can then be attached using self-tapping screws. The holes are 3.5mm diameter, so we suggest a #6 screw. The mounting holes for each cluster are co-planar, so it will be easier to design flat plates using the provided hole patterns, and fabricate them using 2D methods such as laser cutting in addition to 3D printing. Finally, the mounting hole patterns are consistent between frame sizes, so accessories can be shared between frame sizes when mounted to one cluster of mounting holes.
Here is a slightly over-the-top demo of the accessory mounting system: A super-HD dashboard camera records 1st person video (to an SD card), while 4x USB power-pack/flashlights provide illumination and 5V power. With the addition of these accessories, this modified M4 can provide more than a full day of high-resolution video, with up to 16 channels of bio data and accelerometer data via the OpenBCI board. The dashboard camera also has GPS, and the coordinates and velocity are embedded in the video as a subtitle track. This example shows how many other sensors and sources of data can be combined with bio data recording to add important context.
OpenBCI will be offering a selection of new accessories for M4 as they are developed. Let us know if you have a request for a particular M4 accessory, or any other features for the mounting points or CAD templates. We look forward to seeing what you create!