Table of Contents
Step 1. Clarify The Problem
As the objective of this motion tracking project is to provide the foundation for a fully portable motion tracking system, we must consider the daily abuse this system may take from its users. Users may accidentally drop the system, bump into obstacles, or expose it to unexpected forces.
The innards of any motion tracking system will most likely be extremely sensitive to said forces. Hence, some form of enclosures should be present, which does all of the following:
- Protects the sensors and microcontroller from external forces
- Does not hinder our efforts to be "wearable" without extreme user discomfort
- Interfaces with P10011's human interface device
- Is sufficiently sanitary
- Does not interfere with the sensor accuracy
Step 2. Search Externally
- Biomedical Engineering Society
- FDA has tons of restrictions
- It appears that products for physical therapy devices usually fall under the Consumer Product Safety Commission (CPSC)
- Sara has expressed that we don't need to directly concern ourselves with FDA regulations and such, however, it appears that many enclosures on the market are designed for medical applications- may be a good idea to kill 2 birds with 1 stone
Sensor Enclosures Used on the Market
- Some already in use motion tracking devices are strapped on the subject externally.
- The same company has a body suit that covers all the sensors (very much like a under Armor like suit).
- The sensors themselves are usually enclosed in a box like structure.
- Sensor enclosures on the market come in various sizes based on the chip set inside. For our project the smaller the better. With smaller sensors and enclosures it will create less discomfort for the patient.
- Another aspect to look at is the application of the sensor to the patient. Like previously mentioned most current models use straps. But Dr. G. asked us to apply the sensor directly to the skin of the patient with some sort of addheisive.
Step 3. Search Internally
Most motion tracking devices developed by prior RIT MSD projects were not designed for portable usage, and hence do not have a focus on enclosures.
P08006, however, developed a portable motion tracking system for Nazareth. Upon inspection of P08006's enclosures, it appears that they are simple plastic housings dremmeled or cut to fit P08006's components. P08006's cases are significantly bulky, and would definitely be unsatisfactory for a lumbar application.
P08006 published a document titled "Attachment Methods," which states that the model number for their enclosures was "ABS UL 94 HB, M3 Screws" A picture of the enclosure is shown below:
Step 4. Explore Systematically
Specifications of Interest:
- Sensor Width/Length (desired 1x1)
- Sensor Thickness (desired 1/2)
- Sensor Weight
- Diameter of Wires
- Microcontroller Dimensions
- Microcontroller Weight