Due to the hectic schedules of most people, it is challenging to monitor how as a patient you take your medication. The challenge is more profound among young, elderly and those with chronic conditions where they are required to take several pills in a day. The ripple effect is that patients interfere with their treatment process through neglecting or failing to remember to take medication. To help address this problem, several approaches have been proposed. Some of these include the use of solar pill dispensers, which are mostly manual. Consequently, the current project proposes the production of a working prototype of an automatic pill dispenser that would automatically dispense medication at specified times as per the prescription from the doctor. Apart from ensuring the patient takes his or her medicines by issuing audio alerts, monitoring the patient progression on a mobile application is also possible. The patient’s details are captured in the mobile application and the records of the patient saved in a database. The records can, therefore, be retrieved via the mobile App at any time and the same application used to issue commands for dispensing the medication.

The medicine dispenser, therefore, utilizes a smartphone to update the patient database, and issue instructions to dispense medication at specified time intervals. The dispenser will be controlled using a microcontroller on a wireless connection, with Wi-Fi access, which can also establish a Bluetooth connection in case of power cuts or load shedding. The smart dispenser will also have a fingerprint scanner installed for biometric identification of the patient and accurate dispensing of medication to patients. The current project aims to help patients with many tablets/medicines to take in a day and therefore usually prone to forgetfulness. The smart automatic dispenser will introduce efficiency by prioritizing, organizing and dispensing medication to patients according to the prescription.

1.1         Objectives

The objectives of the project include:

Design and build a working prototype of an automatic pill-dispensing machine that will dispense the medication in a timely, accurate and efficient manner.
Build a pill storage mechanism with an automatic trigger for dispensing medicine.
Develop a mobile application as a user interface between the dispenser and the patient. Thus, instructions issued to the database will be used to regulate the number and time at which the pills are dispensed to the patient. Doctors will also be able to monitor their patient’s prescriptions.
1.2         Background

The use of pill dispensers has been in existence since the 1980s (Lewis, Roberts Jr 1986, Scidmore, Scidmore & Scidmore 1987). Consequently, improvements to the system to make it more efficient have been made and new innovative techniques arose in the subsequent years (Lai 2013, Frischmon, Daly & Renshaw 2017). The need for dispensers arose due to the need to have a reliable, consistent and accurate method of dispensing medications. It is anticipated that the problem of poor response to treatment due to forgetfulness in taking prescribed medication will be sorted. For example, pensioners with chronic illness lack the mental alertness of a young person and are prone to making errors on the time and number of pills to take. Other examples include birth control pills and pills for people living with the Human Papilloma Virus (HIV) that ought to be taken at specific time intervals for the medication to be effective.

The current design houses four pill storage compartments with automatic trigger mechanisms. Several pills can be loaded into one storage chamber and instructions saved on a mobile device specifying the number of pills and time to dispense. The device is designed for use at home and the graphical user interface is made easy to use for this reason. The device is intended to address the issue of accuracy of taking medication and address accidental overdoses or other errors by patients. The device communicates to the patient when, and how many pills that should be taken. The device is intended to address the problem of other smart dispensers with small storage compartments and thus will hold for different medicines that can last approximately for a month.

2.1         Block Diagram

The block diagram of the system is shown in Figure 1 that details the different components of the system while Figure 2 shows the detailed block diagram. Generally, the system comprises of a graphical user interface, control unit, sensors, power source, motor drivers and a dispensing mechanism. The detailed block diagram by Groeteke et al. (2016) was modified and adapted for design because it conforms to the design concept adopted in the current project.

Figure 1: Block diagram of the system

Figure 2: Detailed block diagram (Groeteke et al. 2016)

The smart medication pill dispenser will comprise a source of power and a control unit housing a microcontroller and sensors for both audio and visual alerts to users. Moreover, a graphical user interface to set and schedule the correct prescription specified in the system; motor drivers to dispense the medication; and alerts to ensure the patient is aware when to receive his/her medication. A summary of the elements in the detailed block diagram are summarised below:

Power Supply – A power supply that would act as an AC – DC converter. A transformer was used to convert a 120 VAC signal to 12 VAC then to a 5 VDC supply of power to the microcontroller.
Sensing and Control – The sensing and control devices housed in the microcontroller were used to dispense pills by turning motors on and off. The control unit was therefore utilized to automatically program the number of pills to be taken, and when to dispensing the medication. However, in cases where errors arise the user would input commands via the buttons at the front of the LCD display and thereby correct the mistakes.
Graphical User Interface – The graphical user interface is intended to be a platform for interaction and communication between the system and the users. The user interface would be used to set the dispensing schedule in terms of the days and time to dispense, number of pills etc. The user would be allowed to make changes when the need arises for example when there is a change in medication.
Dispensing Motors – The motor drivers allow the user pills to when the motor is turned on and off as per commands from the microcontroller.
Alerting Components – Audio and visual alerts to the user at the time when the customer is scheduled to take medicines.
2.1.1        Power Module

The power unit comprises of a transformer, an AC-DC converter, and a voltage regulator. The system will use a power supply of 12 V with a current of 2A. A transformer will be used a step down the 120VAC to 12 VAC power, which is then converted to 5 V DC power by use of an AC-DC converter, for use by the microcontroller. The 12 V power will be used by the dispensing mechanism.

Table 1: Transformer requirements

Requirements
Verifications
Steps down 120 VAC to 12 VAC
Oscilloscope measurements are taken to

Similar specifications for the AC-DC converter and the voltage regulator are shown in Figure 2 and Figure 3. The opening voltage was maintained at 1.8 V to 5.5 V before usage by the microcontroller. In contrast, oscilloscope measurements were undertaken to ensure power is within the 1 V to 12 V range.

Table 2: AC-DC converter requirements

Requirements
Verifications
Fully rectifies incoming 12 VAC
Oscilloscope measurements are taken to
Capacitor effectively smooths AC signal so voltage stays

within 1 V of 12 V

Oscilloscope measurements are taken to

Table 3: Voltage requirements

Requirements
Verifications
Voltage output stays within 4.5-5.5 V
Oscilloscope measurements are taken to
2.1.2        Microcontroller

A microcontroller unit (MCU) controls the input and output commands for the operations of the circuit to function. At the set dispensing time, the Raspberry Pi (Graphical User Interface) will issue commands on the number of pills to dispense and turn on the signal. Once the mechanical operations are complete, a signal is sent to the microcontroller to turn off the system. Table 4 shows the requirements and verifications of the microcontroller.

Table 4: Microcontroller requirements

Requirements
Verifications
Operating Voltage: 1.8 – 5.5V
Verifying Voltage Regulator should ensure incoming

Microcontroller Voltage

2.1.3        Sensor Module

Optical and light (IR – Infrared) sensors were installed on the device for alerts to users and also to send signals to the microcontroller on whether a pill has been dispensed or not. This is achieved through the rotation off the rollers. An LED light would notify the user where the medicine is dispensed from.

Table 5: Sensors requirements

Requirements
Verifications
Operating Voltage: 1.8 – 5.5V
Voltage applied to sensors measured with multimeter
Sensors send signal out when beam is broken
Sensor output signal measured with multimeter
Broken beam signals are distinguishable
Successive output signals were shown and measured with

oscilloscope

2.1.4        Graphical User Interface

A 3” LCD display acts as a graphical user interface between the system and the user. The GUI is powered using a Raspberry Pi, where information such as the number of pills, scheduled times, etc. are entered and saved. Instructions would then be sent to the microcontroller at appropriate times to dispense the medicine.

2.1.5        Motor Drivers

Stepper motors were selected for use to rotate accurately and dispense the pill at specified time intervals. Consequently, quality control of the motors is very strict to ensure the patient gets the correct dosage of medication is dispensed. The motors will be powered by their own voltage regulator out of the power supply and will accept incoming instructions from the program through the microcontroller

2.1.6        Alerting Components

An LED light and speaker will alert the user through visual and audio prompts to take the medication. The microcontroller will control turning on and off of the signals.

Table 6: Alerting component requirements

Requirements
Verifications
LED turns on between 4.5 V and 5.5 V
Voltage applied to sensors measured with multimeter
Speaker turns on between 4.5 V and 5.5 V
Voltage applied to speaker measured with multimeter
Speaker emits sound when turned on
Sound is audible to human ear
2.2         Physical Model

Jinfeng (1999) proposed the use of CATIA, a 3D software model for the design of devices to simulate the final design before manufacturing commences. Other software that are used for 3D CAD design include Solidworks (Shih, 2014), Tinkercad (Tinkercad, 2017) etc. In the current study, Tinkercad was preferred due to its ease of usage to prepare 3D CAD design models and 3D printing (Tinkercad, 2017). Consequently, the software was adopted for the design of the dispenser thus eliminating the need for many prototypes to check if the design is feasible. Therefore, the use of the software led to huge cost savings. The top/plan view, front view and side view/elevation of the physical 3D model the automatic pill dispenser are shown in Figure 3, Figure 5 and Figure 5 respectively. The top plan in Figure 3 shows the pill dispensing housing unit with the outlines of the 4-pill storage devices.

Figure 3: Plan view of the physical 3D model of the automatic pill dispenser

The front view of the physical 3D model of the pill dispenser in Figure 4 shows the control unit, the pill storage units, LCD display for visual prompts and a speaker for audio prompts. Moreover, the LCD display also had user input buttons for control of commands by the user.

Figure 4: Front view of the physical 3D model of the automatic pill dispenser

Figure 5: Elevation of the physical 3D model of the automatic pill dispenser

The complete set up of the dispensing mechanism of the automatic pill dispenser can be observed in Figure 5. Care was taken to ensure proper alignment of the LED and light sensor that was installed underneath the rollers of the dispenser. Other parts such as the microcontroller, control unit, motor drivers, power unit, and shafts are housed within the pill dispensing units.

2.3         Circuits

The control and dispensing mechanism Arduino circuits are shown in Figure 6 and Figure 7 respectively.  A standard Arduino Uno board was prepared to test the functionality of the system.

A potentiometer was connected to the circuit for the LCD display.

Figure 6: Control unit circuit

Figure 7: Dispensing mechanism circuit

3.1         Labor

Table 7 presents a summary of the labor costs for the project. The total cost is estimated to USD 18,000.

Table 7: Labour costs

Hourly rate ($)
Total hours
Total = Hourly rate*2.5*Total hours
Designer 1
40
150
6,000
Designer 2
40
150
6,000
Designer 3
40
150
6,000

18,000

3.2         Parts

The cost of parts is shown in Table 8 showing the major parts and fittings to be purchased. The total approximate cost of the parts is USD 115.

Table 8: Costs of parts

Quantity
Unit rate ($)
Total cost
Stepper motor
1
60
60
Servo motor
2
20
40
Infrared sensor
1
15
15
Gear
1
0.5
0.5
Raspberry Pi
1
50
50
Microcontroller
1
5
5
LCD
1
10
10
Voltage regulator
1
5
5

115

Frischmon, T., Daly, A. & Renshaw, E. 2017, Automatic Pill Dispenser, engrXiv, USA.

Groeteke, E., Hewaparakrama, J. & Lee, C. 2016, “Automated Pill Dispenser”, .

Jinfeng, P. 1999. Development of a new tool for building 3D parametrization parts library based on CATIA software. Mechanical Science and Technology. 1.

Lai, K. 2013, Automatic pill dispenser, Google Patents.

Lewis, K.E. & Roberts Jr, A.S. 1986, Automatic pill dispenser and method of administering medical pills, Google Patents.

Scidmore, F.A., Scidmore, M. & Scidmore, D. 1987, U.S. Patent No. 4,674,651, Google Patents.

Shih, R. 2014. Introduction to Finite Element Analysis Using SolidWorks Simulation 2014. SDC publications.

Tinkercad 2017. I want to learn about 3D design
. Available: https://www.tinkercad.com.

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