Transcript Design Day Poster - Research

Accessible Medication Dispensing Device
Design By: Kevin Kirby, Daniel Pierre, Nicole Riddle, Ben Roberts, Jordan Smith, and Zac Wingard
Supervised By: Dr. Franz Baudenbacher and Dr. Paul King, Department of Biomedical Engineering
Vanderbilt University - Nashville, Tennessee
RERC 2005-2006 National
Student Design Competition
This pill dispensing device was created for a
national design competition sponsored by the RERC.
The competition rules are as follows:
 Problem: A wide range of medication storage and dispensing systems are available that can
dispense drugs only to a specific patient, and that can reduce medication errors.
 Aim: A moderately priced and dependable device that is easy to use and safe.
Design History
Our approach evolved significantly throughout the design process. The
advantages and disadvantages of three previous conceptual designs are discussed
and pictured below:
 Baffles on the conveyor belt line pills in a single file to be
chopped one by one using a CCD array guided wire saw.
 The Rho’Lix® linear slider and it’s shaft are set in ball
bearings. The bearings are supported by the enclosure.
 There was uncertainty in the process, and issues relating to
integration with the current market’s diverse pill dimensions.
 The drill chuck attaches to the shaft. The drill motor is held
in place with the aide of PVC piping and pipe clamps.
 The cutting and dispensing design was overly complex with
questionable reliability.
 The nail gun is housed in a support structure comprised of
metal angles.
2. Pill Tray Blade Array System:
 This design shifts the pill sorting burden to the user.
 An array of blades chops the entire tray simultaneously.
 The user burden, blade array power needs, and
mechanical complexity led to concept abandonment .
3. Blister Pack System:
 Pills of all shapes and sizes are uniformly packaged in
environmentally sealed, evenly spaced blister packs.
 It is mechanically simple to sort, cut, and dispense.
 The design requires supporting technology, specifically an
implementation of a universal blister pack, so it was
abandoned.
Final Design Details
Products by E-pill:
 Med-Time ($230)
Lacking features:
 MD.2 ($750)
 CompuMed ($1,000)  Pill information input
The final design delicately balances the need for a safe, simple device and the
need for a reliable, feasible product:
 No automatic sorting
 No auto pill-cutting
 Limited storage
Electrical Design:
 The tray positioning system consists of a USB controller connected to a
laptop, which controls the motors-actuator positioning system through
a series of electrical relays.
 The modified nail gun is controlled in the same manner.
The process of taking pills from multiple prescriptions can be repetitive and
confusing, especially to the elderly and the disabled. This is of prime concern to
pharmaceutical companies, as this is the very market they are targeting. A
device that combines multiple medication sorting with pill cutting and scheduled
dispensing would obviously be very beneficial to this demographic.
Safety Considerations
A myriad of safety concerns exist, including:
Improper pill dispensing – number or type
Pill cutting failure
Pill residue
Exposed razor blades on the pill tray
Solenoid misfiring – trauma / electrical hazard
As such, this device is only suitable for caregiver operation, in its current state.
Many more ergonomic and safety measures would have to be instituted in order
for this device to be operated by the users specified in the design competition.
 All of the circuitry is implemented on breadboards and
connected via the USB controller to a laptop containing the
control program.
 Each tray is molded to be pill-specific and replaceable.
 Clients: A wide range of hypothetical clients are specified by the competition. They all have
various ailments that can make using a device like this difficult.
There is already an existing market for this product, and it is about to get
bigger. Some health insurance companies are now offering price incentives to
customers who buy doubly large pills and halve them to save money. Any device
that can cut pills easily will be valuable, especially to the elderly and the disabled.
Some competing products from a current player in the market are discussed below:
A prototype was created that proves in concept the functionality of this design. A
commercially available version of this product would need to account for several
practical considerations:
 The majority of the enclosure and the pill tray is
constructed from a polycarbonate material.
1. Conveyor Belt System:
 Specifications: The dispensing device must be able to slice pills/tablets into halves. Ideally, it will
interpret a container’s bar code, and have the ability to track and schedule medication doses. The
device should be appropriate for use in a client’s home or in a clinical setting.
Market Analysis
Prototype and Results
 Each pill slot on a tray is referenced to a unique 4-bit binary encoding
adjacent to each slot.
 The 4-bit number will be read either by a photodiode array or a surface
height sensor, and then passed through the USB controller.
 A USB barcode scanner assists with loading the pills and scheduling
them properly.
Mechanical Design:
 Troughs assist the user to manually load pills into pill-dimension-specific trays.
 Polyurethane tabs support pills in the pill tray.
 The pill tray and blade tray are attached together for design simplicity.
Cost Estimate
The following table shows a comparison between the prototype cost per
medication versus a mass-produced equivalent. A unit dispensing between 8-10
medications could be produced for under $1000.
Prototype and estimated mass produced product costs
Mass-produced
Mass Produced Cost
Part
Prototype Cost
equivalent
(Estimate)
Housing
$300
ABS Plastic
$20
Threaded set screw
Linear Motivator
$130
$20
equivalent
Motor
$50
DC Motor
$10
USB Interface
$70
IC Equivalent
$10
Solenoid
$15
Generic
$10
Tray/ Blade Tray
$50
ABS Plastic
$5
Total per Medication
Unit
$615
$75
Conclusions
 A 12 volt drill motor rotates a smooth shaft to shift a Rho’Lix® linear slider, thereby moving the
pill/blade tray.
Ultimately, this design uniquely solves a significant need in the market. The
design stands out for several reasons:
 A modified nail gun is used to dispense the pill, chopping it on the blade if halves are to be
dispensed, or popping it out whole if no blade tray is attached.
 The device is a new, novel design that allows for convenient scheduling, pill loading and
medication dispensing.
 The pill tray, with conveniently slanted walls, enables even visually disabled users to load pills into
the device.
 The blade array allows pills to be automatically chopped and dispensed in halves.
 The barcode scanner insures that pills have not expired or been recalled, as well as alerting users
when they need to refill their prescription.
 This is the first step in a modular, expandable device that can hold and dispense an unlimited
number of pills in a compact space.