Team Vision for System-Level Design PhaseDuring the System Level Design phase, our team broke down the two major sensor systems, the major communications systems, possible power systems, and the possible data manipulation procedures. Through our analysis of these subsystems, team Magna Modus determined that the best way to approach design was by conceptualizing a main model that the team feels best fit engineering requirements feasibly while also compiling a list of possible alternate parts to modify that main design. In addition to hardware data acquisition, we must transmit that data wireless to be displayed in real time on some readable monitor. We began with a morphological chart and considered which possible solutions best fit our needs. We then selected which combinations of these concepts fulfilled each requirement. From there, we further narrowed solutions to come to our model design as well as several alternate possibilities. If such a time comes where our design must be altered due to any restrictions, we will keep the alternate systems in mind.
Functional DecompositionFunctional Decomposition
Transformation DiagramTransformation Diagram
Concept DevelopmentIn developing our system level concept, team Magna Modus began with a functional decomposition of our device. Which had 7 steps. Each of these steps correlated with a system, and at the lowest level two systems were needed. We would need to capture two data types, collect that data, transmit data, filter data, correlate data, and display that data in real time and store that data. We then created a morphological chart with 8 sub functions as housing was included in this chart. We developed our solution, and then assessed it for feasibility and requirement fulfillment.
Feasibility: Prototyping, Analysis, SimulationThe system architecture we plan to use is a sleeve housing an Arduino Uno with HC-15 Bluetooth reciever/transmitter, battery system, EMG electrodes, and two IMU motion sensors. These systems are all compatable with one another, and when data is collected from the sensors the bluetooth header on the microcontroller will transmit data to a computer set up to recieve that data. The data will then be filtered and correlated using software, then that software will display the output in real time. The most sensitive design criteria include the limited battery life this system will have in its worst case, and the sheer amount of data that we are to analyze with this device.
- We are considering full current draw of 132 mA for this system to meet our engineering requirement of 8 hours battery life. We would like to achieve anywhere from 4 to 8 hours battery life with an extra battery on backup being charged. This will ensure that the device can survive an 8 hour workday with only one battery swap.
- We are also considering approximately 16 channels of data from our device. This will be 6 from each IMU as well as 4 from the EMG sensors. This amount of data will be hard to display in real time, and we will therefore need to display only the most relevant data.
We believe that it is feasible to reach each engineering requirement, but feel there must be modifications to the Battery Life and Real Time Display requirements. Operating this device for 8 hours straight on max load would require quite a heavy battery system, and to display each of the 16 strings of data simultaneously would require serious computing power that would break our budget.
Design ParametersControl Testing will be required to determine many parameters and targets, but the few we know now are:
- Weight: < 0.75 lbs
- Battery life: 4-8 h
- Display Delay: <300 ms
Morphological Chart and Concept SelectionMorphological Chart
Concept SelectionOur concept development sessions lead to our design of a sleeve powered by a lithium notebook battery with a switching power buffer to feed into an Arduino Uno powering four Myoware Electrodes, and two IMUs. The data collected on these devices will then be communicated via Bluetooth to a PC running our filtering and correlation software displaying in real time on it's monitor.
We decided on this based on the design's:
- Low Weight
- Power Consumption Limitations
- Low Cost
- Wireless data transfer ability
- Ease of Use
Systems ArchitectureThe data architecture of our system will flow from sensors to the Microcontroller. This will transmit to a computer via Bluetooth. This computer will run our software and display our data while saving to a .csv file.
The hardware architecture will be separated into two main components. this will consist of the wearable device and the PC with our software.