156B Week 2
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Planning for the prototype production is of main concern at this point
Pedal layout has been selected after talking to the Sponsor
1 Pedal, and 2 Buttons with indication of direction and syringe selected
Speed control with potentiometer from Robot Kit and Arduino
Selection of Linear Actuator
Waiting for the shipment of Op-Amp
3D printing or Lasercamm of syringe and plunger holder
Accomplishments from Previous Week
Individual component analysis completed.
Purchased AD632 Op-amp needed for compatibility between pressure transducer (+/- signals) and arduino (0-5V)
Finished CAD of prototype of the syringe holder
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Have a linear actuator connected to an arduino and have a building block of programming finished.
Purchase a proper pedal
Have a preliminary prototype showing control of speed and syringe/plunger holder.
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
2nd Objective: sponsor requested that a notification system regarding which syringe was selected be incorporated into the project. (ex. a specific LED light for syringe A or a voice output saying "Syringe A"
2nd Objective: have an automatic valve switch. Therefore the operator would not need to switch the valve opening based on which syringe was selected
sponsor reiterated that prefers one pedal and two switch design
sponsor wants a pedal that has a good amount of user control and not one that is hypersensitive
communicated that a likely outcome of this project would be used for testing, specifically the pressures associated with Compartment syndrome
The system ready pedal design is a little bit awkward to use
The sensitivity of the pedal is crucial because you do not want to expel or aspirate at the wrong time
Aspiration should be brief and only move the plunger 1 cm at a time
Sponsor says that the operating room is relatively clean and there is little chance that liquid can get into the machine components
The footprint of the pedal should be large enough to be able to easily differentiate between the two
The pedal system should be constrained to at least the size of half a laptop, where as the syringe mechanism can be laptop sized
The pressure transducer and accompanying computer is calibrated to reference using air as the medium
The pressure of the operation will be useful for research purposes
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
USE BULLET POINTS
An encoder based pedal of some form is more reliable than a potentiometer based pedal because potentiometers are subjected to temperature effects
temperature can change the resistance of the potentiometer
encoders will be more useful in determine velocities
research Fly By Wire systems that are used in cars and airplanes
research thottle position sensors
Begin FMEA brainstorming to help in determining a design
Be wary that most linear actuators do not have a position sensor
Use the available pedal and linear actuator system to get ideas and try to mimic if needed
If trying to copy the available design, talk to Tom before purchasing parts because some materials are difficult to machine.
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
Risks and Areas of Concern
Buttons or switch selection on the pedal layout.
Buy a button or get a mechanical switch and design a case
Arduino and its power availability as well as a motor shield to incorporate a third motor
Controlling the valve for the selection of drug injection
Resources or Information Required but not Available
Power sources in Lab
Schedule
Describe upcoming milestone
Update Gantt chart.
Budget (list amount spent and amount remaining)
$32 for Pressure transducer circuit components
$1968 left in Budget
Progress on Report and Webpage
Once the final hardware is selected and purchased, we will display them on the webpage.