Rochester Institute of Technologyedge.rit.edu/edge/P09321/public/Week10MSDII/Technical... · Web viewGiven an extra quarter to work on the project, some of the limitations in customer

Multi-Disciplinary Senior Design ConferenceKate Gleason College of Engineering

Rochester Institute of TechnologyRochester, New York 14623

Project Number: P09321

AUTOMATED MEDICINE DISPENSER

Justin Zagorski (ISE)/Project Lead

Rebecca Jaiven (EE)/Lead Engineer

Michael Boquard (CE)/Team Member

Dan Phillips (EE)/Faculty Guide

Ed Hanzlik (ME)/Faculty Advisor

ABSTRACT

The purpose of this project was to design a secure, automated pill-dispensing system utilizing previously existing technology developed by PJSolutions, Inc. This proof of concept was to provide two individuals with a 7-day supply of six medications taken twice a day. The project aimed to simplify the distribution of medication in a way conventional dispensers do not, by providing a set schedule and a secure environment. The proposed design integrated a laptop for development and user interface and a fingerprint scanner for user verification. The primary user will be able to approach the machine and access medication based on a predetermined schedule by a pharmacist. The final product is an aluminum housing that drops cylinders, via Nitinol latches, containing the medication. The cylinders fall down a ramp and stop at the bottom to allow easy retrieval. The housing includes a place to return empty cylinders. In this paper, the design, fabrication, control, and testing processes and results will be described in detail.

Matthew Jones (ME)/Team Member

Felix Feliz (ME)/Team Member

Shuaib Mansoori (EE)/Team Member

John Veenstra (PJSolutions)/Sponsor

NOMENCLATURE

360° Security™ - The ROM will keep a log monitor unit interaction. This includes loading, medication access, delivery, and set up.

ADC - Analog to Digital Converter

AHA – American Heart Association

API - Application Programming Interface

C# - Programming Language

EEPROM - Electrically Erasable Programmable Read-Only Memory

FIFO - First In First Out

FPGA - Field Programmable Gate Array

GUI - Graphical User Interface

I2C - Inter-Integrated Circuit

I/O - Input/output

Mb - Megabit



PCB - Printed Circuit Board

SmartCartridge™ - The entire medication dispenser

SPI - Serial Peripheral Interface

VHDL - VHSIC Hardware Description Language

VHSIC - Very High Speed Integrated Circuits

INTRODUCTION

A significant problem in treating illnesses today is patients' failure to take prescription medications correctly, regardless of patient age. According to the AHA, “ten percent of all hospital and twenty-three percent of all nursing home admissions are due to patients failing to take prescription medications correctly. At any given time, regardless of age group, up to fifty-nine percent of people taking five or more medications are taking them improperly.”

The current medication distribution system is ineffectively designed, if one exists at all. For home systems it is completely reliant on the patient to take their own medication. The systems available currently are the 7-day pill sorters or the pill bottles themselves, but the timing is completely up to the patient, or caregiver, to remember. Along with this is a complete lack of security; unless the storage areas are locked, the medication is accessible by anyone.

Automated sorters and dispensers exist for the home but are unreliable, bulky, or expensive.

The existing systems in hospitals and nursing homes are very insecure. These systems consist of cabinets of medication and rely on an honor system for retrieving the proper medication for a patient. The nurse takes medication and puts a note inside listing what and how much medication they took. This system has no security or reliability, and it is up to the nurse or caregiver to have knowledge of medication, assume the system is organized and

labeled correctly, and remember when to give which patients the correct medications and dosage.

This automated medication dispenser was designed to keep medication in a safe and secure location and allow only patients to have access to their own medication. The medication is dispensed after biometric access is granted to the user scanning their fingerprint. The system then checks for a matching patient and if it is time for their dose. The system is filled by pharmacists so the correct medication and dosage are in correct locations determined by a computer program.

NEEDS

The goal of this redesign was to provide a proof of concept for a new medical dispensing system at PJSolution’s request. This request centered on improving methods used to keep medicine secure and make sure it is dispensed in a timely manner as per a patient’s prescription.

The product incorporated 360° Security™ and a SmartCartridge™. It contained a laptop, interfaced with a USB, and was user-friendly. It properly dispensed medication, had biometric access, and was mobile.

SPECIFICATIONS

The original prototype provided was designed to dispense tool bits in a machine shop. The specifications were to make this more secure, more mobile, and easier to use. A further design requirement was to use Nitinol fiber latches to dispense based on their weight, strength, and compact design. The design was to have a GUI for easy use, and incorporate reliable biometric access through a fingerprint scanner connected to the laptop. The design was also required to be safe to use and ergonomically sound.

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The previous design offered no security; with the improved user design it incorporated security features that only allowed access to the medications theough the biometric scanner. The circuitry was to be within the SmartCartridge™ and on the same board as the Nitinol latches. It also required the incorporation of different levels of user access for the different types of individuals interacting with the device.

The prototype provided was large and bulky and the re-design was asked to be mobile in size, volume and weight. Lastly the device was required to be affordable for use in the home environment.

The patient interaction process is shown in Figure 1A while the user setup is shown in figured 1B.

Figure 1B: User Setup

The proposed implementation into the supply chain will be as followed:

o The pharmacist would fill the unit with the patients’ prescriptions.

o The SmartCartridge™ will be transported by specified delivery personnel to the place of residence of the patient.

o The SmartCartridge™ is then installed in the patients’ home by connecting it via USB and

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Computer

SmartCartridge™

Biometric Scanner

User Approaches the dispenser

User places finger on finger print reader

Correct nitinol latch is actuated and medicine

falls with the use of gravity

Medicine cylinder rolls down the dispensing

ramp

User takes medicineDeposit empty medicine cylinder into return slot

at the rear of the dispenser



ensuring all software is installed and working properly.

o When it is in the correct time window for the patient to take medication, they scan their fingerprint and it is dispensed.

o The user puts the empty cylinder into the return area provided by the SmartCartridge™.

o When patient requires a refill, the SmartCartridge™ is ejected from the system and taken by a transporter back to the pharmacy where it is refilled by a pharmacist.

MECHANICAL DESIGN

Housing

Figure 2 below shows the final concept design for the unit.

Figure 2: Concept SmartCartridge™ Design

It was decided that the housing would be fabricated out of 6061 .09” Aluminum. The unit has collapsible legs with 180° hinges for support and allows the unit to be condensed for ease of mobility. The unit will contain a ramp with a stopping area at the end which will let the dropped medication roll to a stop when dispensed. The dispensing of a cylinder is shown below in Figures 3A and 3B.

Figure 3A

Figure 3B

The housing contains a developed area for the return of the empty cylinders when the pills are taken. This area contains a latched lid for ease of access by the person responsible for refilling and a slot for the patient to insert the empty cylinders.

The inside of the housing contains the circuitry as well as the boards holding the cylinders and Nitinol latches. These boards are supported by rails attached to the inside walls of the housing. A removable lid encases the inside securely, and fastened using spanner screws, which require a special tool to be able to unscrew, increasing security.

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Cylinder Holders

Dispense Ramp

Empty Return Area

Collapsible Legs

USB/Power Input

Figure 1A: Primary Patient Interaction



Fabrication

The housing was assembled using bends in the aluminum and then the removable pieces fastened together using spanner screws. The remainder of the housing was riveted together.

The legs are attached with 180° hinges to allow the legs to stop and support the weight of the device. They collapse along with the ramp to allow for increased mobility, this is shown in Figure 4 below. The ramp is also attached via hinges to be collapsible and sits at an angle to allow the cylinders to drop and roll down to the bottom where a bend in the aluminum will stop it.

Figure 4: Collapsed transport view

Nitinol Latches

Figure 5 below shows a drawing of the Nitinol latches used for dispensing the cylinders when triggered.

Figure 5: Nitinol Latches

The cylinder sits on the Nitinol latches as shown in Figure 5 and when triggered by the correct electrical current the Nitinol contracts a spring and releases the cylinder which will then fall via gravity down the ramp.

SOFTWARE/FIRMWARE

UTILIZATION OF FPGA

Software-Hardware Interaction

Communication between the computer and the SmartCartridge™ was imperative to this project. All information pertaining to the use of this device had to be stored on the EEPROM and feedback information and history lookup had to be communicated to the computer. This offered a challenge not only in selecting the device to be used but also in proper communication.

Development Board

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C yl i n d e r

C yl i n d e r



Communication between the computer and the FPGA was done through USB. The USB carries information regarding usage to the FPGA which writes it to the EEPROM, as well as the dispensing commands, and history checking. Programming a standalone USB microcontroller would be time-consuming and expensive. The Opal Kelly XEM3001 development board, as shown in Figure 6, was selected for this project because it provided its own USB microcontroller, an extensive API, full VHDL support, and ease of programmability.

Figure 6: Top View of Opal Kelly XEM3001 Development Board

The XEM3001 also provided nearly 80 I/O pins, two programmable clock pins, and multiple ground and 3.3V pins. The clock, ground, and power pins were useful for writing to the EEPROM.

EEPROM

The requirements for the 360º Security™ were that all actions performed on the SmartCartridge™ had to be recorded and stored on the SmartCartridge™ itself. This meant each cartridge will have a running record of where it has been, what it has dispensed, and who has interacted with it. This required a large capacity in order to store all of the information. However, size alone could not determine which product was to be picked. Any device on an embedded system has to have a protocol built-in to communicate with the master; the two ways are serial and parallel. Parallel communication would be

asynchronous and each address bit would have its own wire as well as each data bit. However, for large EEPROMs, this would mean that the EEPROM would take up many I/O pins on the FPGA. It was determined that serial would be a better solution. A serial communication is clock based, with just a single input for data in and address in, and a separate signal for data out. Instead of a large footprint of over 20 pins, serial only needs a footprint of 8 pins. The final decision to be made is what kind of serial communication protocol that would be used. There are two predominant ways that devices can communicate serially, SPI and I2C. The difference is how an embedded slave device would be selected by the master device. In I2C, the device would be selected by address while in SPI a wire would connect the two and the signal, whether it was active-high or active-low, would select the device. I2C is better for systems that had multiple slave devices. However, for this application there was only one device so SPI was selected. The Spansion 8Mb (S25FL008A) EEPROM was selected to be used as the main record holder for the system.

FPGA EEPROM Implementation

Due to the volume of information that would be transferred between the computer and the EEPROM over the FPGA, two FIFOs would be created using CoreGen from Xilinx. One would be for computer-to-EEPROM communication and the other would be for the opposite direction. Each FIFO would have two clocks, one for reading and one for writing. This was because the communication between the computer and the FPGA would be governed by the USB clock which runs at 48MHz, and the clock for the FPGA to EEPROM communication would run slower, around 5Mhz.

Fingerprint Scanner

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Due to the high-security measures necessary to ensure proper medication dispense, a fingerprint scanner was required by the customer to be used by patients when it comes time for their dose of medications. Fingerprint scanners come in a wide range of programmability, reliability, availability and price. For this application, a fingerprint scanner with all the libraries for integration into a system was necessary, and at a reasonable price. It must also be commercially available, have a reasonable false-positive reading, and be able to distinguish up to five different fingerprints. The fingerprint scanner selected was the Digital Persona U.are.U 4500 fingerprint reader.

User Interface

Since the interface between the computer and the SmartCartridge™ would be functioning on a Windows computer, a clean and easy to use GUI had to be developed. Due to restrictions on what languages could be used, it was determined that C# would be used as the language of choice. The APIs provided by both Digital Persona and Opal Kelly interfaced easily with C# and communication protocols were determined.

ELECTRICAL

Source and Sink Drivers

The existing schematic was provided by PJSolutions, with latched-input bipolar CMOS high-current and high-voltage drivers. While MOSFETs would provide more heat resistance, they were difficult to find to fit within the specifications needed, thus making them unfeasible for the time table of this project. The existing drivers were chosen based on their availability, price, and reliability. To properly dispense, the Nitinol actuators required the drivers to provide 7V at 700mA for a 1200 ms pulse.

To provide increased functionality, the schematic was separated into four parts – the source board, source component board, sink board, and sink component board. The source board contained the traces for the sourced current, as well as the zener diodes to prevent crosstalk. The source component board is attached to the source board and the FPGA. It contains the ROM, constant current controller, and source drivers. The FPGA is used to select which row to source current through. The sink board had the sink traces that were attached to the Nitinol latches, and sunk 700mA of current. The sink component board attached to the sink board and contained the FPGA connection and sink drivers. The FPGA was used to select which column to sink. The connection grid is shown in Figure 7. Improvements in component selection were done by updating obsolete components from the existing prototype.

Figure 7: Dispensing Array

The overall electrical flow is shown in Figure 8.

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Figure 8: Electrical Flow

The current comes from a wall wart to supply power to the 7V voltage regulator. The 7V regulator supplied the constant current controller which powers the drivers for the Nitinol array which is sunk by the column sinks. The sinks are powered by 5V.

The FPGA, fingerprint scanner, and EEPROM are all powered by the USB which is connected to a computer.

Sensors

Sensors were proposed for this project and investigated. The OPB745 retroreflective was decided to be optimal because of its reliability, small size, and simple concept. Physically being mounted they took up too much space on the board, caused concern in the traces laid and resistors being laid appropriately. Thus they were not implemented in the final design, but tested in prototyping.

TESTING

The software and programming will be tested by installing it onto multiple computers to make sure it runs properly with both Windows XP and Vista. The biometric and different user accesses will be tested using multiple subjects. They will be asked to access

the medication to see if it properly dispenses or rejects the dispensing if need be. Then another test to make sure all users have the correct access to their respective levels will be performed.

The mechanical portion will be tested solely on a pass/fail basis. Size and weight requirements will be checked. The security will also be tested and ensure that medication cannot be accessed by force.

Lastly, the human factors and safety portions will be tested. Ease of use and safety for all ages groups will be tested.

CONCLUSION

Upon completion of testing it was concluded that the circuitry worked as intended. However, the resistance of the Nitinol latches is still unknown and the assembly of the latches proved difficulty in conductivity. It is characterized around 5Ω, but there is a wide tolerance.

There is a functional GUI which is very user friendly and easy to use and all firmware performs as intended. Including the different levels of user access and saving all data to the ROM.

The fingerprint scanner was successful in the sense that it works upon startup and recognized ten different users who set up as patients and accessed the system.

RECOMMENDATIONS

Given an extra quarter to work on the project, some of the limitations in customer specifications would have been resolved.

One of the changes would include further testing of the Nitinol to learn more about their resistance and the assembly problems they posed.

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Another change would be to add the sensors which appeared in the original concept design but had to be cut due to time and space constraints. More time would allow a redesign to accommodate these to detect whether or not a dispense occurred.

The use of MOSFETSs over BJTs in the future is also recommended. MOSFETs are heat independent, more power efficient, and would overall improve the reliability of the sources.

Lastly, interfacing the system with a network would be very helpful. This can be added to help tell someone automatically if a failed dispense happened or there was unauthorized access.

ACKNOWLEDGEMENTS

Special thanks and acknowledgements go out to everyone who put time and effort towards making the automated medicine dispenser happen. In particular we would like to thank Richard Bentley for all his help with the PCB designs and layouts. Thanks to TCS Industries Inc., for supplying us the aluminum and cutting it for us at no charge. Thanks to Ken Snyder for assisting with the soldering of electrical components. And finally, the team would like to thank all the professors at RIT who contributed ideas and helped our design: Dr. Phillips, Dr. Bowman, Professor Hanzlik, and Professor Cliver.

REFERENCES

American Heart Association, http://www.americanheart.org/presenter.jhtml?identifier=107

Horowitz, Paul & Hill, Winfield, “The Art of Electronics” 1989 Cambridge University Press

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http://www.americanheart.org/presenter.jhtml?identifier=107

http://www.americanheart.org/presenter.jhtml?identifier=107

Documents

Rochester Institute of Technologyedge.rit.edu/edge/P09321/public/Week10MSDII/Technical... · Web viewGiven an extra quarter to work on the project, some of the limitations in customer