BioMED - Biomedical Engineering and Design
Project 29: Modular Medical Electronics - Actigraph and Localization Modules
Quick Project Overview
This is a project to build modules for a human biometric monitoring medical device. The modules we're designing and building consist of the Actigraph Module and the Localization Module. Together these modules are the ILAM; the Indoor Localization and Activity Monitor. The ILAM can measure and track activity levels and coarse movements of humans via room to room localization. See the detailed project overview below for an in-depth explanation.
1 Project Timeline
2 Background Research
3 System Requirements and Desired Features
4 Design Solutions
5 Top Level Block Design-Entire Group
-5.1 GUI-Samuel House
-5.2 MCU-Sean Connell
-5.3 Data Filtering - Ian Milligan
-5.4 Power Filtering-Sean Connell
-5.5 RFID Interface-Ian Milligan
-5.6 IMU-Samuel House
7 Testing Evidence
8 Expo Materials
9 Final Video Presentation
Detailed Project Overview
This project aims to build an indoor localization and activity monitor for medical use with humans, the ILAM. The ILAM is a module that interfaces with a main unit created by the IEME Group at OSU. The module will consist of a IMU and a RFID reader. The IMU (Inertial Measurement Unit) will gather activity information while the RFID reader (Radio Frequency Identification) will collect. The IMU portion of this device consists of a three-axis accelerometer, a three-axis gyroscope and a three-axis magnetometer. The magnetometer is employed to help correct drift errors in the gyroscopes. By combining the information from these three subunits, the IMU can detect attitude and heading information as well as the accelerations along each axis. With the correct models and various filtering types, integration will provide us with velocity which will again be integrated to give position change. Any of these values, acceleration, velocity, or position change can be useful in determining activity levels of the human wearing the device. As all the raw data will be collected, other information can be derived with later processing is desired. For instance with the raw data one could perform dead reckoning to determine the path traveled by the person wearing the device. In order to gather absolute location information we will make use of fiducials for position updates. A fiducial is any image, object, or radiation source that has a known location; it's a way-point. As the individual moves about their home they will pass near fiducial way-points. The fiducials will be placed in common static locations, light switch plate covers, hand rails, door frames, etc. By equipping the module with a RFID reader, the fiducials can be made using very small and inexpensive RFID tags. This adds the benefit of each location having a unique identification number associated with it. With the identification number comes location and the absolute position is known. Two types of RFID tags can be used, passive tags and/or active tags. A passive tag receives the energy to transmit its ID from the reader itself, allowing it to be placed and forgotten but also increasing the energy usage of the reader. An active tag is powered and transmits its ID without requiring the reader to supply it, saving the reader power but requiring either a wired power source or intermittent battery replacement. The combination of the IMU and the RFID reader gives us the Indoor Localization and Activity Monitor, the ILAM.
A module like the ILAM would allow doctors to track the long term activity levels of patients in their care. This is very important diagnostic information for elderly patients. As the percentage of the population in the older age bracket continues to grow, enabling the medical industry to care for these patients is crucial to keeping health care on track. This ballooning age bracket is a problem in both the US and even more so in southeast Asia. The need for these devices is growing and the technologies to implement them are now mature enough to enable development of these low power medical devices.
BioMED Team Members