RERC 2005-2006 National RERC 2005-2006 National Student Design CompetitionStudent Design Competition

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.

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.

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.

Accessible Medication Dispensing DeviceAccessible Medication Dispensing DeviceDesign 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

Market AnalysisMarket Analysis

Design HistoryDesign History Prototype and ResultsPrototype and Results

ConclusionsConclusions

Products by E-pill: Med-Time ($230) MD.2 ($750) CompuMed ($1,000)

Lacking features: Pill information input No automatic sorting No auto pill-cutting Limited storage

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:

Final Design DetailsFinal Design Details

1. Conveyor Belt System: Baffles on the conveyor belt line pills in a single file to be

chopped one by one using a CCD array guided wire saw.

There was uncertainty in the process, and issues relating to integration with the current market’s diverse pill dimensions.

The cutting and dispensing design was overly complex with questionable reliability.

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.

2. Pill Tray Blade Array System: This design shifts the pill sorting burden to the user.

Each tray is molded to be pill-specific and replaceable.

An array of blades chops the entire tray simultaneously.

The user burden, blade array power needs, and mechanical complexity led to concept abandonment .

Our approach evolved significantly throughout the design process. The advantages and disadvantages of three previous conceptual designs are discussed and pictured below: This pill dispensing device was created for a

national design competition sponsored by the RERC. The competition rules are as follows:

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.

A 12 volt drill motor rotates a smooth shaft to shift a Rho’Lix® linear slider, thereby moving the pill/blade tray.

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.

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.

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.

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.

The majority of the enclosure and the pill tray is constructed from a polycarbonate material.

The Rho’Lix® linear slider and it’s shaft are set in ball bearings. The bearings are supported by the enclosure.

The drill chuck attaches to the shaft. The drill motor is held in place with the aide of PVC piping and pipe clamps.

The nail gun is housed in a support structure comprised of metal angles.

All of the circuitry is implemented on breadboards and connected via the USB controller to a laptop containing the control program.

Ultimately, this design uniquely solves a significant need in the market. The design stands out for several reasons:

The final design delicately balances the need for a safe, simple device and the need for a reliable, feasible product:

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:

Cost EstimateCost Estimate

Prototype and estimated mass produced product costs

Part Prototype CostMass-produced

equivalentMass Produced Cost

(Estimate)

Housing $300 ABS Plastic $20

Linear Motivator $130Threaded set screw

equivalent$20

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

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.

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 ConsiderationsSafety 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.