Brane Interface is a technology startup working to develop a low cost, compact and non-invasive brain-computer interface using a single atomic layer of carbon called graphene. When a person thinks or moves the brain generates a magnetic field that can be sensed outside of the skull using a sensor called a magnetometer. Currently, the best performing magnetometer is a superconducting quantum interference device (SQUID) but this sensor requires an expensive liquid helium cooling system that weighs on the order of a ton. Because it is just one atom thick and can carry a relatively large current, graphene has the potential to make a room-temperature magnetometer that is as sensitive as a SQUID and yet is small enough to fit inside of an earbud. We believe we may have discovered the most compelling application of graphene to date.
Using our graphene-based magnetometer, Brane Interface plans to link a human brain with an external device such a smartphone by sensing the faint magnetic fields of human thought. Medical applications of the technology include assisting those who have been paralyzed to gain control over robotic limbs using only their thoughts. Consumer applications include enabling people to interact with their smartphone/computer using thought commands in place of touch or voice interfaces.
Brane Interface has built four prototypes to date. The first two prototypes use a polymer membrane as the main sense element and the most recent prototypes utilize a graphene membrane (the inspiration for “Brane”). Each successive prototype is at least one order of magnitude more sensitive than the prior prototype so we’re definitely making progress. We’ve filed multiple patents to protect our inventions.
After completing a computer model using Math-Cad software, we set out to make a proof-of-concept prototype of our magnetic field sensor.
We made the first part of our sensor out of acrylic using a laser cutter.
Using an array of ultraviolet lights and UV-cure epoxy, we applied an aluminum-polymer membrane to our acrylic structure.
Our completed first prototype showed that we could measure an external magnetic field by sending a current through our conductive membrane and measuring a change in capacitance with a multimeter.
We decided to make a much smaller prototype using photolithography.
Etching an array of conductive membranes.
Using a spin coater to apply photoresist.
A single conductive membrane post etch.
A simple photomask used to make the conductive membrane of our sensor.
A flexible printed circuit board used as the sensor’s source, drain, gate and capacitive stator.
A close up view of an etched conductive membrane using an optical microscope.
Our first attempt at making a “real” device using a single atomic layer of carbon.
Searching for graphene using a scanning electron microscope or “SEM.”
Graphene membrane array captured in SEM.
A small feature on a silicon wafer to test a graphene membrane.
Loading a copper-graphene sample into the SEM.
The basic operating principle of a graphene-based magnetic field sensor.
A SEM image of a small strip of graphene next to the edge of a business card. Graphene is really thin!
Searching through several copper-graphene samples to find the best ones.
Several copper-graphene “fly swatters” that are ready for transfer.
Aligning and transferring graphene to a silicon-oxide-metal device.
We met several really smart BCI researchers at our SXSW booth and learned a ton.
A CNBC reporter stopped by our booth and asked for an interview… a huge surprise.
Check it out here.
We still can’t believe Brane Interface won the 2019 SXSW Innovation Award in its category!
Now it’s time to make an improved graphene-based prototype.
Preparing a strip of copper foil for the tube furnace.
Annealing a strip of copper foil in the tube furnace.
Growing graphene on the surface of copper foil with heat, methane and hydrogen.
Applying photoresist to a copper-graphene substrate using a spin coater.
Exposing a photomask with UV light to create a pattern on the copper-graphene foil.
Viewing a copper “puck” suspended on a graphene membrane post etch.
Back in the lab over Thanksgiving break and searching for the best chip to use.
This 100 micron diameter silicon-oxide-metal device, combined with a graphene membrane, will make a very sensitive magnetometer.
It took a few years but our newest magnetometer prototype (shown inside the silver trough of our first magnetometer) should be about 500 million times more sensitive per unit size as our first attempt.
Our equation above shows the importance of current density and membrane thickness.
Only graphene has the current density required to measure the faint magnetic fields of human thought
Graphene is just one atom thick so it is much more sensitive than existing MEMS sensors.
I’m currently a student at Saint Andrew's High School in Austin, Texas. In addition to developing novel BCI and clean energy devices, I also love to read about Roman history and make short films. After college I think it would be fun to challenge tech’s “frightful five” with a series of BCI devices that offer a much more natural way to interface with the digital world. I also want to use the miraculous properties of graphene to lower the cost of clean energy devices.
info@braneinterface.com
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