Assisted Pill Dispenser for User With Tetraplegia

Brian Ambielli, Adrienne Dunk, Paul Kravik, Cheng-Chen (Roy) Lu (Northwestern University)


User has a C4-C5 spinal fracture, resulting in very limited mobility from the shoulders down. Current pill dispensers on the market do not meet user’s needs, since they either require fine motor skills to operate or are out of the user’s price range. The Assisted Pill Dispenser (APD) allows the user to dispense up to seven doses of six different types of pills via independently rotating wheels and a funneling system. The device is completely wireless, capable of receiving and interpreting X-10 signals with its Arduino microprocessor, allowing the user to select which type of pill he/she would like. The user makes a pill selection by using a mouth controlled “sip ‘n’ puff” switch. The only other pill dispenser for a user with tetraplegia costs $10,000 USD to make (Figure 2A), and the material list for APD totaled a mere $210 USD.


The Assisted Pill Dispenser (APD) is designed with the purpose of allowing a user with tetraplegia to self-administer medication as needed throughout the day. To best accommodate the user’s needs, it was important that we fully understand the user’s background and requirements, as detailed in the next section. We will analyze our solution to this design problem in the next few pages, and elaborate on how it not only surpasses our user’s initial requests, but it also seamlessly integrates into our user’s environment and demands little else from the user than tasks he/she is already used to performing.

Final Design Pictures

Pictures referred to as A and B from left to right: A. Final design of the Assisted Pill Dispenser. B. APD prototype without final wiring


Our client for this design project is the Rehabilitation Institute of Chicago (RIC): America’s number one ranked rehabilitation hospital for the past 19 years5. Our user is a patient of a rehabilitation therapist at the RIC. We were tasked with designing a pill dispenser to allow the user to self-administer medication while in bed; our user has a C4-C5 spinal fracture, has no lower body mobility, and has very limited upper body control. The user desperately needs this device, as currently he/she can only afford 4 hours of care from a hospital aid per weekday, even though it is recommended by a physician that he/she have 10 hours of professional care 7 days a week. During times without aid, he/she relies on friends, family and neighbors to come over and administer pills multiple times throughout the day; this is truly an inconvenience for our user’s friends and loved ones. These friends and family members are often busy during the weekends, which is also when our user receives no professional aid, so having a way to self administer medication during these periods alone is critical to our user’s well being. Comparable products already designed for users with tetraplegia are both few and far between, and well out of our particular user’s price range (some reaching upwards of $10,000 USD3). More affordable dispensers do not offer the independence our user is looking for, by either requiring fine motor skills to operate, or by dispensing medications at set time intervals. It is imperative that we design a reliable, easy to use, and cost effective device to fit our users needs, and the needs of countless others affected by tetraplegia.


User Observation During initial user observation, we learned the true extent of our user’s limited mobility. Only able to move his/her head about six inches from side to side, and move arms a small amount up and down, we were forced to scrap our purely mechanical solutions to the design problem in favor of a combination of electrical and mechanical options. Our device meets our user’s needs by working with activation from the sip ‘n’ puff switch currently in place in our user’s home. The user can select which pill he/she wants by making a selection on the Progressive Computer, which sends a unique X-10 signal to the proper wheel in our device. The pill then falls through the center hole, into a funnel, and down a tube that brings the pill within our user’s range. It is also incredibly affordable when compared to other options on the market: only $210 USD.
Expert Interview Much of the research conducted at the beginning of the term proved obsolete or inappropriate as the weeks went on: after user testing, we recognized that radical design changes were needed in order to compensate for a lower than anticipated range of user mobility. We approached Electrical Engineering and Mechanical Engineering professors for recommendations to modify our design. They provided valuable expertise for us to finalize our electrical circuitry, programming and mechanical operations. Each part of our final design is tailored to fit the needs of our user.


Design Concept User controls when and which dose of pills he/she wants to take by using the sip-n’-puff controller, which makes a selection on the Progressive Environmental Control Computer screen, referred to as the Prog. The Prog sends a wireless X-10 signal to our device, which completes a circuit for the motor and turns the user’s selected wheel, dispensing a single dose of medication. This dose then falls through a funnel and down a tube into the user’s range. Material choice, device placement, and integration with our user’s existing technology maximize design performance, while maintaining an aesthetically pleasing exterior: the APD is truly a marriage of form and function.

Aesthetics: Aesthetics play a major part in making design decisions for the APD. All materials except for electronics and the gears and shafts are made of clear acrylic, providing up to 97% transparency. This transparency is key to determining when the pill wheels need refilling; a quick glance is all it takes. Low coefficient of reflection throughout the device allows the user to observe the inner workings of the APD, including its rainbow colored wires, symmetrically placed wheels and gears, visually intriguing wheel cuts and fantastic electronics (Figure 1). Units of the pill dispensers sit radially symmetrical to the funnel and the container, creating a geometrically pleasing pattern. In addition, the laser cutter used to cut the pill wheels is capable of engraving names, numbers and symbols to the user’s desire, adding a degree of personalization to each APD manufactured. Such meticulous considerations regarding aesthetics ensure that the device does not look imposing in our user’s room, and seems to fit

Computer and X-10 Remote Control: The APD is integrated with a GEWA Progress Environmental Control Transmitter (Figure 3). This Transmitter is capable of remembering and sending X-10 signals at the user’s request on screen. The APD has six X-10 receivers whose corresponding signal are programmed into the Progress. The display on the computer is a computer page with six selectable buttons that would correspond to each pill. When a button is selected, the corresponding X-10 signal is sent out and the APD interprets the signal. The user interface for the Progress is a Sip and Puff gooseneck which our user already uses in his daily life and has a low learning curve. The device is mouth operated by the user in bed and it is movable so it can adapt to the user slipping and moving in bed. Compared to other methods of activation, this is the superior method. Other methods such as buttons or arm activated selection processes would be inefficient spatially as well as require an amount of dexterity and precision that the user might not have. Our design only requires that the user be able to operate with his mouth and breath.

Microchip and Motors: The device converts an electrical signal into motor movement through an Arduino Microprocessor and basic circuitry. DC motors were selected for their low cost and ease of use. While the use of a DC motors requires the use of a sensor for each motor to make the pill dispenser accurately dispense one pill, the lower cost makes the slightly more complex design more desirable than a more expensive yet more accurate stepper motor. The 90 RPM DC Motor is geared down with a ratio of 2:5 which allows for the pills to be dispensed quickly. The microswitches that are activated after a pill has been dispensed make sure that the dispenser stops at the appropriate time consistently.

Funnel and Tubing: The delivery method consists of three parts, funnel, hard tubing and soft tubing with goose neck. The funnel directs all pills to the tubing with 100% success rate. We tested with aspirin and different types of confection for 100 runs and obtained zero failure. The hard polypropylene tubing is bendable when heated; low coefficient of static friction allows the pills to travel smoothly through the tube. Finally, the soft tubing will be tied up along the last foot of the gooseneck. Soft polypropylene tube directs the pills to a spoon at the end of the tube, around which the user would wrap his mouth around to receive the pills. Since all of our materials are transparent, the user can easily identify the pills to double check the correct pills are being dispensed.


Comparison to Existing Products There really is no comparable product on the market. Most of the pill dispensers on the market focus on reminding people to take pills on regular intervals (Table 1 and Figure 2). However, our user’s requirements were that the pill be able to be taken on an irregular basis, when the user needs them. In addition, there is no existing device that accommodates the user’s range of motion while in bed. Our design is able to meet the needs of the people in this specific market and provides an important part of independent living.

Other pill dispensers on the market

Pictures referred to as A, B, C from left to right: A. Johns Hopkins 10,000 dollar pill dispenser for a person with tetraplegia. User uses a mouth stick to make pill selections, which fall through a tube into user’s range. B. Automatic pill dispenser on the market. This alternative dispenses medication at a specific time interval. Does not allow user to take a pill whenever he/she would like. C. Generic pill organizer on the market

Device Able to administer sufficient number of pills? Able to administer pills on demand? Able to be used while the user in bed? Cost (USD)
Johns Hopkins Dispenser

(figure 2A)

Yes Yes No 10,000
APD Yes Yes Yes 210
Automatic pill dispensers on the market1

(Figure 2B)

Yes No No 20-100
Pill organizers on the market1 (Figure 2C) Yes No No 20-1

A comparison of current pill dispensing alternatives to our design. Factors examined were the ability to administer pills on demand, how many pills the device could hold, if device could be used in bed, and cost.


Cost to build the APD totals to 210 USD, including the expensive Arduino chip, motors and gears. Expenses can be greatly reduced as we refine the design. The APD is certainly fit for mass production and marketing, since it serves a large community with very specific needs. The APD can easily be modified to work independently of a computer system and
Conclusion In conclusion, the APD meets all necessary criteria for easily getting the pills from a storage area directly to the user’s mouth with little effort on the part of the user. The design incorporates

•    The user’s existing Programmable Progress that the user already uses in his everyday life

•    X-10 sensors to send remote infrared signals to minimize clutter by wires at the bedside

•    6 separate units of DC motors, storage discs and Micro-sensor switches to turn each wheel, dispensing one dose of medication as needed by the user

•    Flexible storage for different combinations of pills

•    Wall mountings to keep the main body of the device on the wall and out of the way

•    Semi-flexible tube to allow adequate velocity to get the pills from the device to the user’s mouth

•    Detachable tube that can be washed in the dishwasher

•    Beautifully designed and constructed to integrate form and function

Our user needs a medication dispenser so that he can independently take his pills as needed throughout the day. The APD has met all necessary requirements while exceeding even the design team’s expectations by achieving an aesthetically pleasing form. Within the next month, the Automated Pill Dispenser will be installed in the user’s house. It will be mounted up on the wall so that it is out of the way and does not add clutter to the user’s bedside. Because of the clear materials and clean lines, the design is pleasing to look at and will not make the room feel oppressed with yet another medical system on the wall. Costing approximately $210 for the first prototype, the design is easily reproducible and cost effective. Further, this is an untapped market that could benefit greatly from this new product increasing the independence of people with tetraplegia around the globe.

1. Online Shopping for Electronics, Apparel, Computers, Books, DVDs & More. Web. 28 Apr. 2010. <>.
2.    Science, Industry and Business: the Innovations-report. Web. 28 Apr. 2010. <>.
3.    Woodlake Technologies – Assistive Technology Solutions. Web. 28 Apr. 2010. <>.
4.    RIC | Ranked #1 Rehabilitation Hospital in America. Web. 28 Apr. 2010. <>.

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