Medication Dispensing Device
RERC ACCESSIBLE MEDICAL DEVICE
OPTIMAL DESIGN
Team 6
Kevin Villani,
Eva-Marie Suarez,
Jacquelyn Masse
November 11, 2005
Outline
I.
Introduction
II.
Design
1. Basic Components and Locations
2. Vacuum Fan Requirements
3. Robotic Arm
i. Servo Operating Theory and Circuits
ii. Vacuum retrieval assembly
4. Pill Capture and Cutter
5. Storage assembly
6. PDA and LabVIEW
7. Barcode Scanner
8. Dispensing Assembly
9. Pathway of the Pill
III.
Budget
IV.
Appendix
1. USB 6008/6009 Device Block Diagram
INTRODUCTION
With individuals taking a growing number of different drugs, the market
has developed several ways of making medications easier to handle. Products
range from simple containers to store pill dosages per day, hand held pill cutting
tools, and medication reminder alarms to more expensive, complex devices.
Many of these devices can be problematic for people with poor eyesight, limited
fine motor skills or mobility, Parkinson’s Disease, or other physical ailments. The
lack of existing products on the market to suit such clientele gives rise to the
need for an automated medical device that will administer medication to the
patient in an accurate, dependable manner.
The device will be cost-efficient and reliable. It must remain accessible
and easy to use for individuals who lack fine motor control, are vision impaired,
or are limited by unsupported vertical access. The size and portability should be
suitable for residential or clinical settings. Automation will be the device’s most
distinguishing feature. It will mechanically regulate medication of 1, ½, or ¼ pills
of various sizes and shapes and will manage many different medications at once.
Ideally, the device will have alarms to signify the time medication needs to be
taken or refilled. Information regarding dosage amounts, times, and expiration
dates will be internally stored and a tracking system will record a history of
dosages dispensed.
DESIGN
Basic Components and Locations
Air Control Valve (6012)
Servo motor
Arm
Rotating plate (retrieves
cut pieces)
110°
95.5°
Cutter Assembly
Base
Arm travel arc
Vertically translating
vacuum port
Dispensing tray/Funnel
Retrieval location
Storage
Sliding plate(removed
during loading)
Funnel
Figure 1
Components are located within the case, located to allow for ease of
access and ease of replacement. Above is a component breakdown of major
assemblies within the device.
Vacuum Fan Requirements
Based on the maximum pill weight and the minimum pill thickness a
vacuum requirement is identified. This requirement provides the differential
pressure across the medication to ensure the medication can be removed from
the storage module and delivered to the rejection
P = F/A
assembly. By using simple pressure and weight
F =mg
definitions a relationship for the required differential
A= πr2
pressure is attained. By measuring several over-the
Therefore,
counter and prescription medications a minimum
P= mg/ πr2
thickness was found to be 4 mm, while the maximum
(Equations)
mass was approximately 1000mg. Substituting these
values into the equation below a net pressure difference required was found to
be 6.4kPa. In more traditional units of vacuum this corresponds to 1.94 in Hg.
Keeping in mind that traditional vacuum systems draw a vacuum of 27 to 29 in
Hg. Centrifugal fans systems are evaluated in meters of water, the range of
operating head is 0.5 to 1.5 meters of water. The corresponding required
differential pressure is 0.0622 meters of water, well within expected operating
head.
To satisfy this requirement we have selected a fan impeller from a dirt
devil 6000 series battery vacuum. The vacuum sells on-line for approximately
$55 however, the impeller is also available for sell for $4.95.
Using a centrifugal fan impeller has several advantages over other
vacuum generating options. First the price centrifugal fans are lower. Secondly, a
centrifugal fan reaches shut off head. This shutoff head prevents drawing too
high of a vacuum while still maintaining the fan in operation. This means that for
our application there is a requirement that a pill be held by the vacuum tube and
moved. By reaching shutoff head the pump will continue to spill however moving
no air unless air slips into the system either from leakage by the pill or across the
pump. Third this pump weighs less and is far easier to construct than other
vacuum assemblies.
The vacuum fan assembly will be driven by 120 VAC power source Fan
and system characteristic curves are used to determine the flow rates and
pressures within closed systems. By measuring the differential pressure across
the fan at various speeds and volumetric flow rates, a graphical representation of
the fan operating characteristics can be achieved. Coupling this operating
characteristic curve and a system operating curve; specific system flow rates and
operating pressures can be determined by the points of intersection between the
various curves, commonly referred to as “fan laws”.
System operating curve
Pump characteristic and system operating curves
Figure 2
Robotic Arm
The major transport method employed by this device is the use of a
robotic arm. The robotic arm was chosen not only for the “bells and whistle”
quality it possesses but also because it has a wide margin of versatility, one to
one control over medication through process, allows for verification of medication
at point of retrieval. The Robotic arm is used to move medication from storage to
the cutting assembly and from storage to dispensing. Several additional actions
are required from the arm as part of cutting sequences and loading sequences.
The Robotic arm will be constructed of high density polyethylene due to its
strength and chemical resistance. This arm has two axis of motion. The first is a
horizontal swing arm with a range of 180 degrees limited to 95.5 degrees for this
application. The orientation of the swing arm allows for the placement of the
vacuum assembly above any assembly located along the swing arm arc. Control
of the swing arm is via a servo motor and the PDA running LabVIEW through a
data acquisition box(DAQ). This servo motor requires a command wire besides
a ground and positive 6V power supply. The command wire requires the use of
one analog channel from the DAQ box. Operating the servo motor requires the
following knowledge.
Servo Operating Theory and Circuits-A servo
is a geared microprocessor controlled DC motor.
Generally servos sweep over a 180 degree arc.
However, removing the stops within the servo and
changing the programming allows for operation at arcs
greater than 180 degrees. The servo controls of the
robotic arm require only 90 degrees of rotation. A
probable candidate for the servo required is Parallax 6
volt servo pictured to the left. The operating circuit for
this servo is in Appendix I. Basic servo theory is
Figure 3. Servo
centered on changing the pulse width of the control
motor(Parallax)
signal. This change in pulse width corresponds to a
position of the servo motor. A 1.0
ms pulse rotates the shaft all the
way counter-clockwise. A 1.5 ms
pulse puts the rotor at neutral (0
degrees), and a 2.0 ms pulse will
position the shaft all the way
clockwise. The pulse is sent to
the servo at a frequency of
approximately 50 Hz. The
relationship between the pulse
width and the rotor position can
Figure 4 (Lyxnmotion)
be seen in the picture above.
The second axis of movement for the robotic arm involves the rotation of
the vacuum tube and retainer about its axis. This allows the vacuum tube to drip
into storage containers and to gently place medication on subunits. Control over
this action is given to the servo motor controller slaved to the PDA through the
DAQ box on a single analog channel. The arm and second axis (containing the
Arm
External view
Base
Vacuum servo
Arm servo
Vacuum control
valve
Vacuum supply
Vacuum pick up
tube
Internal components
Figure 5 Robotic arm
vacuum assembly) can be seen in the component breakdown illustration below.
Further the action of the robotic arm unit is pictured below:
Vacuum Retrieval Assembly-This assembly is tasked with the retrieval
of pills from the storage module for delivery to the pill capture and cutting station
at dispensing set points. The assembly is made of five components; pill retrieval
vacuum tubing, supply tubing, servo motor and the proportioning valve. A
vacuum is drawn on unit through the proportioning valve setting up a pressure
differential across the medication. This pressure differential holds the medication
Action in horizontal
direction
Top view
Axis
Vacuum assembly
Arm
Vacuum action
Side view
Retrieval angle
axis
45.0°
arm
Medication storage
90.0°
Robotic Arm
Action
Swing angle
(vaccuum supply not
included for simplicity)
Figure 6
Base
in place for transport to the pill capture and cutting station. Pressure is passed
back through the proportioning valve allowing a discharge pressure to release
the medication from the pick up tube. The type of device was chosen to reduce
the possibility of drawing multiple medications in a single pass. This single event
can then be related more accurately to pill retrieval numbers.
From the discussion of vacuum fan requirements the area of the pill
pickup tube is approximately 1.26e-5 m2 or a circle with a 4mm diameter. The
proportioning valve is located at the rear of the robotic arm and controls flow into
an out of the pill pick up tubing. The vacuum pick up tube and retainer is rotated
into position by a servo motor, approximately a 45˚ change in retainer position.
The proportion valve is a Burkett (6012) 3-way valve operating with the
following technical requirements. When deenergized the valve is positioned to
relieve pressure to atmosphere. When energized to valve positions to permit
vacuum pressure to be felt in pick up tube. The required operating voltage is
24V DC±10% or 24V AC. Maximum operating temperature is 130F at a
maximum viscosity of 21 cSt. The response times for this valve are opening 7-10
ms and closing 7-12 ms (DC).
Pill Capture and Cutter
Design limitations of design 1 are directly answered with the secondary
design of the pill capture and cutting device. This design removes the need for
the user to load the pill manually while still retaining as high accuracy as
segmenting the medication dosage. As seen in research pills and tablets do not
need to be cut along a score line to remain consistently segmented correctly. In
fact personal research was conducted to cut tablets lengthwise with high
accuracy. With this in mind the secondary design approach to pill capture and
cutting is centered about geometry. Assuming all pills or tablets that shall be cut
have a point of symmetry about them the capture swing arm shaped as an arc is
capable of placing the point of contact between the pill and the swing arm about
this center of symmetry. In the same motion align the cutter along this center of
symmetry. This orientation allows a pill to be segmented in half, by repeating the
process ¼ segments are achieved.
To examine the operation of this device a closer look into the geometry of
the argument is needed. By looking at the complete circle and taking into account
the changes in the x direction of the circle, a cosine wave form can be produced.
The portion of this waveform of interest is from 0-90 degrees. Where 90 degrees
is the minimum pill size relates to the maximum negative adjustment of the cutter
assembly. Conversely, 0 degrees relates to the maximum pill size and zero cutter
adjustment. By mechanically and continuously sampling the x position of the arc
a direct connection is made to the adjustment of the cutter assembly.
In this device the arc and cutter assembly are not linked but rather in
contact with one another. The set up of the cutter assembly places the blade of
the cutter at the center point of the arc and the “feeler” side of the cutter in
contact with the arc. A plumb line is drawn from the innermost portion of the
contact of the arc and cutter assembly. This plumb line extends a length slightly
larger then the magnitude of the cutter adjustment. With each smaller pill the arc
is rotated by torsion spring tension against a slight axial spin tension thereby
positioning the pill to the center point. Concurrently the underside to the arc acted
against the cutter “feeler” and spring tension (of cutter assembly) to reposition
the cutter assembly. Note from previous discussion the changes in the x-direction
of the arc are translated one for one to the cutter assembly. With this set up any
symmetrical medication can be centered across the cutter blade providing
accurate non-approximated center points.
Secondary stage
Primary stage
Cutter
Swing arm
Figure 7
While the positioning capability of this sub unit are key, this sub-unit
contains or supports the major differentiating function of the overall device as
well as provides a far superior design to design one. The functions of this
assembly are to accept, capture, cut and deliver medication. Capture and cutting
have already been covered in a preliminary seems. To evaluate the function of
this sub assembly a complete sequence of operation should by addressed to
understand the interconnection of devices. The assembly consists of a stepper
motor, three ball bearing linear tracks, worm gear and pinion, torsion spring, two
axial springs (one for the swing arm and one for the cutter assembly), base,
cutter arm, stage, and sliding secondary stage.
The base unit carries the weight of all components. The three ball bearing
linear tracks are mounted parallel across the base perpendicular to the cutter
arm. The main stage is mounted to the top two ball bearing linear tracks and is
coupled to the worm gear shaft via treaded couplings. This permits the stage to
project out from the base is the direction of the linear tracks by action of the
Figure 8 Cutter Operation cycle
pinion gears coupled to the stepper motor. Noting the accuracy of the linear
movement of the stage is not associated with the accuracy of the cuts. Rather
the gearing is designed for higher rates of projection and retraction. Most
important to this actuator is the ability to satisfy cutting conditions. Those
conditions are that the stage is fully retracted and the arc is in contact with the
cutter “feeler”. The base is also used to attach the cutter arm as well as routing
power lines.
The main stage contains the swing arm and secondary stage. The action
of the secondary stage is to slide open perpendicular to the motion of the main
stage providing a means for removal of segmented medication. The action is
provided through the main worm gear energy by coupling that energy to a slotted
groove located at a hyper-extended region of the main stage. The hyperextended range is at a distance equal to the maximum opening range of the
secondary stage past to point of acceptance of medication. The most crucial
component in the design is the swing arm. Balancing the load of three springs
allows for the alignment of the cutter. To begin in the closed position the swing
arm is at approximately 80 degrees (maximum negative adjustment). This
position reduces the opening axial spring deformation while loading the cutter
spring. The main stage is projected outward to the medication acceptance point
where the opening spring force builds (assisted by the cutter spring) to open the
swing arm against the torsion spring tension. At the medication acceptance
located the swing arm is in the minimum adjustment position, providing the
maximum area for deposition of the medication. After deposition of the
medication the main stage is retracted. Now the torsion spring overcomes the
opening spring and cutter spring tension due to the relaxed nature of the opening
spring. This positions the medication and forces the cutter into position. At the
fully retracted position the cutter is engaged after conditions met. The cutter is
Servo
Blade
Cutter Arm
Tablet
Swing arm
Torsion spring
Secondary stage
Tracks
Figure 9 Cutter Side View
operated through the use of a servo motor in contact with the cutter arm.
Rotating of the servo forces the cutter arm shut against torsion spring tension in
order to put force on the tablet. The blade is shaped as to pass by the retention
arm and in between the swing arm. This cutter will not cut completely through the
pill. Penetration of approximately 1/3 of the tablet thickness is required to cause a
cut segmentation (determined experimentally with the use of a commercially
available pill cutter.) Below is illustration of the cutter component breakdown and
operation. At this time the main stage is again projected past the acceptance
region to the dispensing region. To prevent damage to the opening spring a
secondary spring with a spring constant lowered than the elastic region of the
primary opening spring begins to give way. At this point the swing arm is
balanced in the open position allowing the medication to be forced against the
swing arm and off the secondary stage. The pills fall into an intermediate storage
bin which rotates to a position outside the stage assembly. This rotations position
another identical storage bin below the secondary stage. This operation is
preformed to prevent confusion of segment sizes during subsequent
segmentation (¼ segmentation) as well as facilitation for transport to the rejection
assembly. The secondary stage movement is provided by a channel and pin
assembly. The pin engages the channel just past the acceptance region and
provides the anchor point for the stage to slide outward using the primary stepper
motor energy.
Storage Assembly
The storage assembly consists of a of a storage reel segmented into
twelve containers, a storage reel cover, fill cover and stepper motor. The storage
reel is designed based on a fishing tackle holder. The compartments within the
storage reel are designed such that the outer edge of each compartment is
deeper then the inner portion. Inner and outer depths are connected by a
continual ramp. This allows the medication stored within the compartment to fall
by gravity to the lowest position as medication is withdrawn. A reference slot, in
blue, will provide the PDA with a reference position so that compartments can
accurately be determined. Possibly the use of a limit switch will provide sufficient
control over the outer edges of the primary compartment allowing the PDA to
have an indication of storage reel position for reference. Rotation of the storage
reel is controlled via a stepper motor mounted to the outer edge of the storage
reel. During storage reel rotation the storage reel cover remains stationary. The
reel cover contains two openings, one for withdrawal of medication by the arm
and one for filling storage locations. To cover the fill location during operations a
user operated fill cover is positioned over the fill location sliding out from below
the fill funnel when needed.
Control of the stepper motor is accomplished through the use of a stepper
motor controller slaved to the PDA through the DAQ. This requires the use of 3-4
four digital pins of the DAQ. Compartments are determined as a number of turns
from the reference slot, this allows the PIC controller to retain positive control
over the position of the compartment relative to opening. A potential draw back to
this type of control is in the case of power loss. The stepper motor position will be
Guide pin channel
Secondary Stage Motion
(View from below)
Change in distance of
secondary stage
Secondary stage motion
Guide pin
Main stage motion
Figure 10 Secondary Stage motion
unknown. To combat this situation the PDA will return the storage reel to the
reference position and then reposition the reel to the proper opening. The
storage assembly is pictured below showing the component exploded view on
top and a typical rotation of the unit below.
Reference slot(blue)
Stepper motor
Axis
Funnel
Storage reel cover
Reference slot(blue)
Storage reel
Storage
Assembly
Retrieval location
Fill cover (user operated)
Fill location
Funnel
Figure 11 Storage Assembly
PDA and LabVIEW
Using a PDA has many advantages. The dominating advantage is the
storage capabilities. By incorporating a PDA into the dispensing device, a large
amount of information can be stored without the risk of losing it if power outages
occur. A data acquisition box will control the cutter and robotic arm however; the
PDA allows a separate program to control the calendar, clock, timers, data
storage, and initiation of the device’s actions.
The program for the device will be written in LabVIEW. It will act as the
computational link between the data stored in Excel (also stored on the PDA) and
the data acquisition device. It will track the number of pills dispensed and
remaining and will control the timing of the alarms for expiration date and
dispensing. The alarm and displays will output through the existing PDA screen
and speaker.
Since the keys on the PDA are very small, a separate keyboard will be
connected to the system for the users to access when turning off the alarm or
entering pill information. A barcode scanner also needs to be integrated into the
system. These two items will be inputs into a USB hub that then directs the
information through a USB port to the PDA, where the information will be stored
and dealt with by LabVIEW and Excel. We can use TRENDnet's TU-400E, a
highly integrated 4-port USB hub. It consists of one upstream and four
downstream ports. It is compact, light-weight, requires no external power, and
only costs $6.78.
Figure 11: 4-port USB Hub
The PDA chosen for this design is the Tungsten E2, made by Palm. It has
non-volatile memory which means that the data will be safe even if the PDA runs
completely out of battery power. Only palmOne models and the import Sharp
Zaurus line of Linux PDAs are the only PDAs on the market to use 100% nonvolatile memory. This feature is especially important because of the complicated
process of storing and programming the dosage times and the need to keep a
history of the pills dispensed. The Palm includes a calendar that we may
incorporate into our timing and alarm functions. It saves energy by entering a
sleeping mode, but will wake up to beep or vibrate. The PDA is also affordable at
$150.
Figure 12: Tungsten E2 Palm PDA
In order for the PDA to communicate with the motors, a data acquisition unit is
required that will be connected to the PDA via a USB hub. Using 12 digital I/O
lines, 8 analog input lines, 2 analog output lines and full speed USB interface the
DAQ made by National Instruments (model number NI USB-6008) has plenty of
capability for our needs. Nine of the digital input/output lines will be used to
control the motors. The motors that control the cutter, temporary storage stage,
robotic arm, and storage tray consist of two stepper motors and three servo
motors. Three of these lines will control the function of the three servo motors;
the other 6 lines will control the function of each of the stepper motors, 3 lines for
each motor to control the output enable, direction, and speed. The digital output
from the data acquisition device will be connected to each of the motors via a
buffer circuit that will protect the data acquisition device as well alter the signal to
meet the signal requirements of each of the motors. The data acquisition box will
also accept inputs from the switches used to indicate when the motors have
reached a home position. These signals will be accepted by the data acquisition
device via the analog input ports. The LabVIEW program will translate these
signals into a digital signal utilizing Boolean expressions. The DAQ, as well as
the USB HUB and the PDA are all compatible with Windows 2000.
Figure 13: Data Acquisition Device
Below is a flow diagram of data through the device.
Barcode
Scanner
PDA
Keyboard
USB Hub
Data
Acquisition
Unit
Motors
Figure 14: Flow of Data
Barcode Scanner
A barcoding system will be implemented to reduce errors during the
loading process and to identify the stored data for each medication. Almost all
prescriptions that come from the pharmacy utilize a barcode to link the
medication to the patient's history, this ensures that the correct medication and
dosage is being given to the patient. The medication dispenser will also utilize
this UPC number provided by the pharmacy to store similar information on the
PDA. The UPC number is simply a reference number that will correspond to a
row of data in a Microsoft Word Excel spreadsheet that is stored in the PDA. This
row of information will contain the UPC reference number, the number of pills
stored in the module, the required dosage, the container number in which the
pills will be stored, the number of times per day the medication should be
dispensed, the time at which each dosage should be dispensed, the size the
medication needs to be cut down to if necessary, and the expiration date. The
information stored in the excel spreadsheet can then be used to track the
medication within the LabVIEW program. This data will be pre-programmed in
the device to reduce the amount of effort required by the user for initial set-up.
When a prescription needs to be loaded the client will scan the
prescription using the barcode scanner located on
the device. The scanner uses a laser to scan the
bars and measures the intensity of the light
reflected via a photo diode which generates a
waveform corresponding to the width of the bars
and spaces. The decoder receives this wave and
converts it to the 12 digit number that will be used
Figure 15 - IDAutomation
USB Barcode Scanner
as a reference number in our application. The keyboard wedge scanner chosen
for this application is the IDAutomation Plug 'n Play USB Barcode Scanner. This
particular scanner was chosen based on its easy installation process, USB
connection which is compatible with the PDA, and built-in decoder which
transmits the data as if it were typed from the keyboard. This scanner also does
not require the use of any additional software, thus reducing the overall cost of
the device and the amount of memory needed for the PDA. The scanner
automatically inserts the 12 digit number wherever the cursor lies regardless of
the program being used. When a client needs to reload the device, the barcode
on the prescription is scanned. This code is then entered into the LabVIEW
program and compared to each reference number stored in the excel
spreadsheet. When a match between the scanned number and the reference
numbers stored in the spreadsheet has been located, the LabVIEW program will
withdraw the number of the storage module for that medication from the
spreadsheet, and then activate the microcontroller to send a signal which will turn
the storage container apparatus until the container with that assigned number is
in the loading position. After more pills are added the LabVIEW program will
prompt the user to enter in the number of pills added and the new expiration date
using the keypad provided, and will store this new count and date into the excel
spreadsheet. The program will then use the data of the spreadsheet indicating
the size the pills needs to be to either move the pills to the cutting assembly or
leave the pills in the storage assembly. The number of pills added that was
entered by the client is then used to indicate the number of loops the cutting
assembly must complete in order to cut all the medication.
The spreadsheet will also provide the necessary information for
dispensing of the medication. Where the time that the medication needs to be
dispensed will prompt the dispensing portion of the LabVIEW program to run.
The number of pills to be dispensed is also extracted from the excel spreadsheet,
indicating the number of loops the program must perform, one loop for each pill
dispensed.
The use of the barcode system allows for the device to become more
automated, thus reducing the possibility of human error. This reference number
provides the necessary link between the LabVIEW program and the excel
spreadsheet containing the data about each medication. If a barcoding system
were not used, the client could easily forget which pill is located in which storage
container, possibly loading a medication into the wrong container which will then
cause that medication to be cut and dispensed incorrectly since the data from the
medication previously stored in that container is being applied to the new
medication. If the medications have different dispensing times and dosages, an
error in the loading process can severely affect the health of the client and may
even prove fatal. The use of the barcode minimizes the possibility of these errors
occurring due to its high accuracy. The accurate reading of the barcode can be
attributed to its start and stop characters as well as the checksum feature. The
start and stop characters indicate where the code begins and ends which allows
to machine to detect whether the code is being scanned forwards or backwards.
This feature allows the user to scan the code without worrying the direction the
code is facing, thus reducing human error.
The 12 digit number read from the barcode is
also verified using the checksum number,
which is the last digit of the code. This
number is calculated by a series of
computations using each of the individual
digits of the 12 digit code. If the number
calculated from the 12 digit number read by
the scanner does not match the last digit on
the barcode, the number is discarded and the scanner re-reads the barcode. This
feature again reduces error, ensuring that the number read by the scanner is the
same number on the barcode.
Dispensing Assembly
The medication will be deposited into a container that is easily accessible
to the client. Since the client must activate the device to begin the dispensing
process after the alarm has sounded, a secondary guard, such as a trap door,
against inadvertent exposure of the medication would be redundant and thus not
necessary.
Pathway of the Pill
Storage assembly
rotates to correct
storage module
User inputs
number of pills
added and
expiration date
Pills poured into
container
Pill needs to be cut
(indicated by data stored
in spreadsheet)
No
Barcode
scanned
Yes
Blade cuts pill into
halves
Feeler places the
blade in the center as
indicated by the swing
arm
Pill needs to be cut into
quarters
Turntable makes
another rotatation
Yes
Pills remain in storage
container
Cutting process
repeated
No
Secondary stage moves
so pills fall into turntable
Pills released one at a
time onto secondary
stage of cutting device
by robotic arm
Swing arm forces pill
into center
Robotic arm moves over
to the storage container
assembly
Storage container
assembly rotates so the
correct storage module
is accessible to robotic
arm
Vacuum pump is turned
on
Alarm sounds when
indicated by the timer
that a medication
needs to be dispensed
The alarm turns off
Security code entered
by client
Correct
Security code compared
to stored code in
microprocessor
Change in current
sensed by vacuum
Vacuum lowered into
prescription container
Incorrect
Cut pills moved back
to storage container by
robotic arm
Alarm will continue to
sound
No
Continues suction
Trap door pushed open
by an actuator
Client removes dosage and
closes trap door
Process repeated until
the full dosage is
completed
Ye
s
Vacuum lifts from
storage module with pill
Pill released into
dispenser container
BUDGET
Below is the anticipated cost of the project based on the prices of the individual
components:
Quantity
Unit Price
Extended
Price
Supplier
1
$15.00
$0.00
dirt devil
1
$4.95
$0.00
dirt devil
4
1
1
$15.00
$3.00
$10.00
$60.00
$3.00
$10.00
lyxnmotion
Digikey
Digikey
4
$6.00
$24.00
BTI Supply
1
$5.00
$5.00
PDA
1
$250.00
$150.00
Palm
USB Hub
1
$6.78
$6.78
Trednet
1
$145.00
$145.00
National
Instruments
1
$100.00
$100.00
(Several)
6
$12.00
$72.00
lyxnmotion
1
$50.00
$50.00
lyxnmotion
1
$120.00
$120.00
IDAutomation
1
$100.00
$100.00
(Several)
Component
vacuum pump
motor (donated)
vacuum
impeller
(donated)
Plexiglass
Power Cord
Actuator
Tracks with
rollers
Brail dots (self
adhesive)
Data
Acquisition for
USB
Wires &
Electrical
components
Servos
motor/stepper
motors
Servo controller
unit
Barcode reader
Mechanical
Components
TOTAL
(development)
$845.78
APPENDIX
Appendix I – USB – 6008/6009 Device Block Diagram
(Source: http://www.ni.com/pdf/manuals/371303e.pdf)