This paper reports on the design, fabrication, and testing of a 3-axis acceleration switch intended to serve as an early warning for traumatic brain injury (TBI). Mild TBI (colloquially termed “concussion”) resulting from rapid acceleration of the skull has been rising in the public consciousness with recently increasing awareness of the dangers and long-term health risks associated with it. The sensor described here is an array of acceleration switches designed to cover the range of acceleration associated with TBI, and to do so with no external power draw until an acceleration event within this range occurs.