156B Week 4
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Prototype is completed and ready for testing.
Report writing has started for the 1st draft of final report.
Looking at maintained foot switches
Ready to purchase lead screw and motor to drive syringe
Accomplishments from Previous Week
Prototype is functional and working with a potentiometer adjusting its speed.
Built a circuit with the prototype and a momentary button to reverse the direction of the motor.
Momentary button is controlling direction of the motor
Programmed LED's to indicate selection of syringe and direction
Syringe holder currently under fabrication in machine shop
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Meet with the sponsor and have a new refined update in our FMEA (everyone).
Complete most of the introductory part of the report and template (everyone).
Finalize and purchase the linear actuator and encoder (Ethan and Kevin).
Build a prototype of the foot pedal interface with purchased pedal (Oscar and Thomas).
Use purchased parts to finish pressure transducer circuit and begin getting feedback (Shawn).
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
After seeing the system work in its most rudimentary form, some auditory signal, such as noise from the motor, will be helpful in knowing that the syringe is working.
Compared to the model shown, a finer lead screw pitch would be preferable to be able to control finer motions
The model found in Shawn has a pedal add-on, but it only operates in Start-Stop mode.
Be sure that the flange does not move out of place.
The commercial potential of the system is still uncertain because the department must evaluate the advantage of pursing a legal action to make this product.
There exist a patent for a similar project that is not in production.
Each syringe system could use its own individual pair of LED's to show the direction it is set to.
This can be placed on the syringe holding fixture or on the base of the structure
Momentary switches like the one demo to change the direction are not intuitive
The housing on the pressure transducer should be flexible enough to fit the phone jack
Similar to the syringe device found by Shawn, a knob to disengage the lead screw to be able to move the plunger holder to fit a particular syringe would be nice.
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Good Presentation
Nice hardware progress!
Good CAD and justifications
I am concerned about over constraints
binding may occur
could you reduce over constraints
moment can occur
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
Leadscrew design should use a ball screw and utilize a smaller thread size
Vibration might be an issue in the syringe actuation
Will the buttons be protected in anyway?
An overall emergency shut off would be a good idea
Have you thought about a timing belt/pulley system?
To help with safety concerns can you have a display in view of the doctor that shows direction and syringe selected. This would be more clear over LEDs
Add another pressure transducer to ensure safety in case other one fails.
Rugged circuits for motor driver shield fro arduino
Use ball screws and a high turn/inch
Make pedal more of a __/ design rather than just / so weight of foot doesn't cause unwanted motion
Risks and Areas of Concern
Having trouble finding large maintained foot switches, might go with pedal switches which are relatively cheap.
Resources or Information Required but not Available
Encoder programming
Schedule
Write programing code for pedal when it arrives and incorporate into existing prototype
Write programing code for encoder and incorporate into existing prototype
Update Gantt chart.
Budget (list amount spent and amount remaining)
$32 for Pressure transducer circuit components
$12 for steel rod, springs, and bearings
$100 for pedal
$1856 left in Budget
Progress on Report and Webpage
Working on completing the required deliverables.