In this paper we present a modular software protocol for extending a variable dataspace within a microcontroller firmware system (MCU) that allows robotic sensor data to be streamed via the Robot Operating System (ROS) architecture. This protocol copies the data formatting structure inherent to ROS messages and implements a local DN bridge to allow for asynchronous bi-directional data transport over any communication channel. We implement a demonstration of this system on a mobile robot test bed to manage communications between the sensor data acquisition MCU and the primary control computer, and use this test case to measure the efficacy of the protocol through latency and packet loss, and tracking validation by comparison to other measurement systems on the robot.