Product Design

The design of the device was customer driven. Every step of the process was done with the engineering objectives and customer requirements as first priority. Below, the design related to each engineering objective is explained. Other links within this section define further detail to what is discussed here.

Pills are dispensed in a cup

The compartments were made large enough to hold a communion cup that could be picked up out of the compartment by a user with limited fine motor skills and dexterity. The CAD design and later plastic steps were designed with holes in them so that the cup would sit up out of the plastic by half an inch as well as room around the cup for easy cup retrieval.

Pill containment requires less than 4 lbs. of force to access &

Pills would be contained if device is subjected to 3 lbs. of force

A magnetic latch system was chosen to contain the pill cups in each compartment. A two piece lid was chosen that uses two screws to attach the two pieces. The heads of the screws were then used as the metal surface that two magnets could attract to keep the lids closed. The strength and shape of the magnets were carefully chosen to keep the compartment opening force below four lbs. The first magnet, for one side of the compartment, was rated at 2.44 lbs and the second at 0.87 lbs. The combination of these two magnets ensure that the compartments are easily opened and closed by the user without the compartments opening on their own if the device were dropped.

Visual Indicator: 1000 mcd. light output

Each compartment contains an LED light that lights up when that compartment’s dosage is due to be taken.

Audio Alarm System: 80 dB

With the use of a speaker, an amplifier and data storage space, two alert voice messages are included in the device’s alert system. The first voice message recorded is to alert to take the pills within the lit compartment. The second voice message is to alert the user if they are trying to access their pills at the wrong time and encourage them to place the pills back in the compartment.

28 pill taking times

The 28 pill compartments were a specific request from the project’s sponsor to allow for 4 dosage times over 7 days. This was the keystone to the entire design. Multiple basic prototypes were made to determine the best arrangement. Based on issues with having enough space for lids to open, the stair-stepped arrangement was implemented as shown.

CAD Model Picture of the stair stepped arrangement of compartments

Adjustable Pill taking times and dates with 4 options per day

In order to program the dosage times as mentioned in the 28 pill compartments that are for 4 dosage times over 7 days, an LCD screen with three buttons will allow the caregiver to enter morning, noon, evening, and bedtime dosage times.

No in-depth menus

With this requirement, a programming structure was set up to require only 3 levels. A sample screen schematic is shown above.

Programmable option for early dosage up to an hour

Included in the programming code is a grace period which allows the user to take their pills up to 30 minutes early.

Large text screen

In order to allow larger text, limited menus and low power usage, an LCD screen was carefully selected. It allowed for four lines of text with minimal graphics requirements. These specifications aid in the expected battery life of the device.

Large buttons for programming

Three 1” diameter arcade buttons were chosen in order to enable users with limited fine motor skills to easily navigate the menus to set up and program the device.

Programming on off switch

A slide on off switch was selected to perform as a programming on off switch. The switch has an electrical life of 6,000 cycles as well as a mechanical life of 6,000 cycles. The switch was also easily integratable with it’s terminal being a solder lug. The switch would ensure that the programming wasn’t altered by accident or if the buttons were to be bumped.

Entering dosage schedule < 5 minutes

To enter the dosage schedule, the programming setup has only a few simple steps.

Transferable User Activity Storage for at least 512 Mb

In order to allow the caregiver to monitor the pill taking activity of the user, a 4GB Micro SD was incorporated into the device design. The Micro SD card is designed to be left in the device while not in use. Once the caregiver wishes to retrieve pill taking activity, they will navigate the menu and select Export Data. This will initiate the data loading on to the Micro SD. When this has finished, the screen will display a message notifying the caregiver to retrieve the Micro SD card. The Micro SD card can then be put into the USB adapter and the data transferred onto a computer for review and medical records.

Device training < 30 minutes

Every step of the design process was made with simple operation in mind. The device is designed to sound a voice alert and light an LED to tell the user to open the lit up compartment to retrieve their pills. The alerts are designed to continue alerting the user until dosages are taken. If a user tries to take pills outside of the scheduled times, the device will sound an alert with a voice message discouraging the user from taking their pills at that time. For the caregiver’s usage of the device, simple programming and easy to navigate menus contain simple language and instructions that make the operation self-explainable. One of the menu options is data retrieval, which simply requires that the micro SD be removed and a text file of the user activity be accessed at a computer.

Power Cord uses a standard 120V/15A standard us outlet

To fulfill this objective, a power supply was chosen that works as a switching DC supply so it’s small, lightweight and efficient. It fits in power strips without blocking other outlets. The output is regulated to supply a steady 9V up to 1000mA (1 Amp) of current draw. At the other end of the adapter is a standard 5.5mm/2.1mm barrel jack with a positive tip. This supply is designed to interface easily with a plug adapter to plug into a 100V-240V AC wall power plug in. This item also works with Arduinos, and anything that has a 5V regulator.

Battery Life > 4 hrs.

After some calculation of the power requirements of the device, a large battery that is commonly used in RC cars was chosen. This lithium ion pack is made of 3 balanced 2200mAh cells for a total of 6600mA capacity. The cells are connected in parallel and spot-welded to a protection circuit that provides over-voltage, under-voltage and over-current protection. The cables attached to the battery are rated for 2A. The included protection circuitry keeps the battery voltage from overcharging and over-use which means that the battery will cut-out when completely dead at 2.5V.

Cost less than $700 to produce

The budget constructed after the final design was approved. The budget at that time showed a device build cost of $660. The final actual cost of the device came in at $658.

Fits within a traveling bag

The final dimensions of the design device came out to be 10.5” x 5” x 12.75”.

Lightweight < 10 lbs.

Between the device housing and electrical components, the design of the device was calculated to be close to 6 lbs.