Poster Presentation

Today the Design Project Poster Session took place. We brought our poster panels to recitation, and mounted our poster on the board. Then we (nervously) proceeded to give our five minute presentation, talking about our device, its features and the design process we followed to reach our final result. We each took turns and presented the slides that we each knew most about.

It was hard to try to touch on every subject and choose which were the most important features, but we decided to introduce only what we thought was most relevant to the problem we were trying to address.We really enjoyed watching all the other teams present, and seeing the plethora of such different and great ideas that our fellow students had come up with. Frankly, we were quite surprised at the originality of all the designs, and at how we had thought of some similar ideas but applied them to such different machines.

After all the presentations were finished, we placed the posters around the room to look around and see what our teammates had done, as well as to allow the TA a closer look. We were very impressed by the projects our recitation put forward. We got to see the posters in detail, and finally the winning BE100 Design Team for our section was announced.

Unfortunately, it wasn't ours, but we still feel really proud of the work we did, and the amazing device we accomplished to design. This picture shows David, Connie and Julie presenting (the RxH was awesome by the way). Lastly, we wanted to say congratulations to the winning team, "Team Turtle" (Michael, Sofia and Vivek)! Your docking idea was great, and we look forward to see it hanging in front of the BE department (OG).

We have come such a long way from the beginning of the year, when most of us didn't even begin to understand what Bioengineering was. Although we had to work hard and learn new skills, we are now on our way to becoming some of the best Bioengineers out there. The experiences and people in this class have made our experience at Penn unforgettable. We wish you all good luck, and hopefully we'll see in class next semester... :)

Love, Quacks and Happy Holidays,

DuckHunt Designs Crew

Last Meeting

Last night Team Duck, AKA Duckhunt Designs, had its last meeting before the poster presentation. We went over all of the slides, deciding who would say what and making some final changes in our presentation.

After this, we met with our TA, Alicia Nelson, who gave us some helpful tips to help us present the day after.We also ran through the presentation various times, to get practice and see what it would feel like talking about our device in front of a classroom full of people. This was one of the hardest parts for us, because public speaking is never easy, so we thought that a little more practice couldn't hurt. That's why, after listening to Alicia's comments, we went back and decided to practice on our own for the night. Hopefully this will help us give a great presentation!

Slide Nine: Feature/Benefit chart

This was one of our favorite slides to put together, because we could easily showcase all the features we had included in our device and why (even the really cool ones that made our device great - according to us). This was a good chance to show how thought-through our device was, and although ultimately because of time and space constraints we couldn't include all the features we wanted, we included some of the most essential, interesting and important ones.

Slide Eight: Detail Designs

We struggled with many different aspects of our device, and came up with a variety of original solutions to our challenges, but two of the biggest hurdles to overcome were:

Device to push the pills down:

Our device dispenses pills by pushing them down a track, but we had several options as far as what was going to impulse them to go down the “tube”: a conventional spring, a motorized plate or a constant-force spring.

First of all we considered using a regular spring. This would be convenient as they’re easy to find and very cheap. These would be coiled at the top of the track and as each pill was to be dispensed it would uncoil, until being at its maximum extension when all the pills had been dispensed. However, they don’t apply a constant force when they’re completely coiled as when they’re uncoiled, which would be hard to calibrate and might compress the capsules too much, potentially destroying them.

Secondly we considered using a motorized plate. This would provide a constant force, and – by making it the same size as the casing – it would correctly dispense the casings. However, this option was electronically very complex, as a circuit and motors would be required for them to be functional, so they would take up more space and energy. Also, this made it more probable to pose problems, as the more complex the device is the more chances it has of failing.

Finally, after much research, we found constant force springs: a durable and inexpensive type of spring that works in a very interesting way: the force it exerts over its range of motion is constant. That is, it does not obey Hooke's law. Generally constant-force springs are constructed as a rolled ribbon of spring steel such that the spring is relaxed when it is fully rolled up[1]. This could pose problems by applying a force to only one side of the pill capsules. Attaching a plate to the bottom of the spring, which would be lowered through guides on the walls would help the force be constantly applied to the entire surface of the casing, and therefore make this an easy way to apply a constant force without needing to motorize the device. Therefore we chose the last option, because it was inexpensive, was available in the desired sizes, optimized space and didn’t require motorizing, thus leading to a less costly and simpler device.

Analgesic storage options:

First of all, we thought of storing the pills in blisters, which would keep the pills sealed and therefore not let them spoil. However, that would mean that pharmaceutical companies needed to develop a new way of producing the blisters so they could fit in the device. Secondly, we thought of having strands of plastic packets with precut lines in between each dose, which would be cut when they were to be dispensed. However, these could potentially jam the machine or – if not cut at the exact location – open the next packet, jam, or get stuck under the blade. Another idea we had was to store them in gelatin-based clear capsules, which would be edible and able to store more than one pill. However, these could stick to the walls and be susceptible to heat, as well as easily break. Finally, we decided to use clear plastic capsules, of 2x2x2cm, which would allow more than one pill to fit into the capsule if necessary, be reusable and easily refillable, inexpensive and hard to deform (ideal for our spring and roller dispensing system).

[1] As it is unrolled, the restoring force comes primarily from the portion of the ribbon near the roll. Because the geometry of that region remains nearly constant as the spring unrolls, the resulting force is nearly constant (Springs How Products Are Made, 14 July 2007).

Slide Seven: Operation description

This was a hard slide to put together, because we essentially had to explain how every single component in our device works to fulfill its function, analyzing it and However, thanks to the previous work we had done (e.g. the functional diagram, the specifications, the conceptual design, etc.) and because we were very clear about what our device was going to have, it was just time consuming. Another challenge we faced with this slide was trying to clearly and intelligibly explain all the things we could see visually with words, which is one of the hardest things to communicate, especially when you're talking about a fairly complex device. Here is how our device works.

Body:

The patient controlled oral analgesia device is rectangular in shape (20x12x10cm) and is sized to accommodate 200 (2cm x 2cm x 2cm) pill casings; each casing will be capable of holding more than one tablet of medication. The casings will be stacked vertically and positioned within a rectangular tube. Each tube will accommodate 10 pill boxes(1 tube=10 pill boxes); consequently, the device will be housing 20 tubes. Within the device four rows of tubes are aligned vertically in the y-direction and five rows of tubes are aligned vertically in the x-direction.

Discharging mechanism:
A constant force spring positioned within each rectangular tube will be applying a downward force on the packaged medication. The constant force spring is a pre-stressed flat strip of metal composed of spring material that is coiled around itself or a drum. When deflected, the spring material straightens as it distances from the drum. The straightened material stores energy as a result of its tendency to assume its natural curvature. This results in the rotation of the drum which in turn applies the constant force.*

The conveyor belt (approximately 2cm in length and 2cm in width) is positioned horizontally 2cms below the tube of packaged medication(as visible in FIG 3). The conveyor belt will be connected to a DC motor which will in turn be connected to a microprocessor. There will be a total of 20 conveyor belts; one for every tube. The conveyor belts will be positioned as to rotate in the positive x-direction. One motor will be supplying the energy required to rotate them. The microprocessor will make possible for individual rotation of the conveyor belts. Physicians, pharmacists or patients will have the capability to program the device to dispense medication at predetermined times.

The conveyor belt will rotate a distance of 2cm in the positive x-direction and the horizontal force resulting from kinetic friction between the bottom surface of a pill case and the surface of the conveyor belt will discharge the pill casing located at the bottom of the rectangular tube and will allow for the subsequent pill box to be pushed down by the constant force spring to the point where the bottom surface of the subsequent pill box makes contact with the surface of the conveyor belt. The discharged pill box will fall into a chamber where the patient will have access to the box of medication by simply lifting a flap door and reaching in for the medication.

The design of the apparatus allow for pharmacist/physician to fill the device with a variety of medications. If each tube is designated one type of medication the apparatus will be capable of holding 20 different types of capsules. Upon dosage request the patient will have the capability of selecting between medication “A” and medication “B.” If medication B is selected, the conveyor belt discharging capsule B will be energized while the rest remain stationary.

Power and user interface:

The device will be powered by a long lasting rechargeable lithium-ion battery that will keep the device operating for a minimum of 24 hours without needing any type of recharging. An AC Adaptor Jack positioned in the left face (as illustrated in FIG.1) will allow for the recharging of the lithium-ion battery. In addition to the AC Adaptor Jack, the device will have a USB Port.

This will allow for the physician or pharmacist to extract data (e.g. delivery history) from the device’s hard disk for analysis. The numbers of interactive keys in the devices are kept to a minimum in an attempt to make the device as intuitive as possible. The device will have nine interactive keys (POWER BUTTON,YES, NO, REFILL, DOSE, LAST, Emerg., Up Down) and an automated fingerprint identification system. Upon dosage request the patient will have to have their fingerprint scanned to confirm that the medication is being delivered to the individual whom it is prescribed to. If the patient is unable to consume the requested dosage for whatever reason, he/she will be capable of requesting a secondary dosage by pressing the interface key labeled “Emerg.” However, the patient will have access only to a minimum number emergency pill boxes. The quantity of emergency doses that a patient is allowed to receive is ultimately dictated by the physician or pharmacist. If a patient wishes to view the time that the last dose was consumed, the patient can simply press the key labeled “LAST” and the information will be made visible in the 9 cm x 7cm LCD display located in the front face of the device.

Refilling mechanism:

The bottom face of the device has an access panel arranged for pivotal movement about a pair of hinges. This door allows for an authorized individual to have access to the inside of the apparatus for refilling of medication or repairing of malfunctioning components. An electromagnet positioned within the apparatus (upper face) will make possible for the unwinding of the constant force spring which will ultimately allow for refilling of medication. If refilling of medication is necessary, the interactive key labeled “REFILL” will be pressed which will in turn activate the electromagnet and consequently cause the constant force springs to unwind. Recognize that upon pressing “REFILL,” the source will be asked to input a code; hence only authorized individual will be capable of refilling the apparatus. If an incorrect code is entered the electromagnet activation will be terminated.

* http://www.directindustry.com/prod/ametek-hunter-products/constant-force-spring-14268-28098.html

Slide Six: GOZINTO Diagram

This was one of the most challenging parts of the project. Not only did we have to divide our entire device by functions (and trust us, a lot of the different components are used for MANY functions), we had to make it concise but complete, clear and self-explanatory.

Needless to say, the functional analysis diagram took us a long time to complete, but at the end it was extremely helpful when putting our presentation together. It allowed us to easily explain how our device worked and highlighted all the most important components we needed to reference. It helped us make sure we had no flaws and that the design was as good as it could be to fulfill the necessary specifications. Therefore, although I was a challenge to put together, ultimately it helped us very much with our project and presentation.

Slide Five: Drawing

To decide exactly what would go into this device, one of the best way of communicating our thoughts for our team was to sketch our different ideas. After we had decided exactly what design we were going to have we made many preliminary drawings, and finally settled for the one we thought the most complete, and then formalized it on a sheet of paper. Once that was done, using software such as Microsoft Word, Photoshop and Paintbrush, we digitized our device to be able to include it in our slides without having to scan a hand-drawing. Well, since a picture is worth a thousand words, here are 3000 to finish this post!

Slides Three and Four: Conceptual Design

Our design choice for the PATO was the Stack Dispenser design. Here are some points as to why we chose this one over all the others:

Useful features:

• Pill containers would allow some adjustability of dose size (several pills could be in each container)
• Multiple dose types possible (a variety of pills could be placed in different stacks with different lockout times)

Main Advantages

Dimensions:

• Lighter and smaller than both liquid dispensers
• Smaller (better space optimization) than the strip dispenser and rotating pill dispenser

Simplicity:

• Easier to work with solid pills or containers than with strips of material
• Pills are readily available and plastic boxes are easily constructed, but more complex packaging of doses would be required for the strip dispenser

In more detail, the PATO uses the Stack Dispenser design because using pill containers would allow some dose adjustability, which was the major disadvantage of the stack dispenser. In other aspects (dimensions, simplicity, and affordability), the stack dispenser’s advantages were superior to those of the other designs. Overall, the advantages far outweighed the disadvantages of the design.

Dimensions:

The stack dispenser was superior to other designs in size and weight. Relying on rectangular tubes would use space much more efficiently than the rotating dispenser, which could only hold one ring of pills around the center without wasting space. The stack dispenser would weigh much less than the liquid analgesic dispensers once the weight of the analgesic was accounted for because the stack dispenser dispenses pills, whereas liquid dispensers would also have to hold the weight of the solvent. This would also make the liquid dispensers larger than necessary.

Simplicity:

It is much easier to work with solid pills or containers than with strips of material. Also, pills are readily available and plastic boxes are easily constructed, but more complex packaging of doses would be required for the strip dispenser. For these reasons, the strip dispenser was too complicated. The liquid dispensers were also more complex than the stack design. A hand-held pump could be unpredictable and inaccurate. The mechanism required to dispense one dose at a time from a syringe would be more complex than the simple process of releasing one pill. Finally, rotational motion is more complicated than linear motion. Thus the stack dispenser won out overall on simplicity. Simpler designs are cheaper to execute, so affordability is an added bonus.

Slide Two: Conceptual Design Options

Some of the different initial design ideas we had applied to a variety of different products, and although we had many more ideas, these are some cool ones.

Liquid Analgesic Dispenser:

• Syringe-like dispenser: Liquid would be pushed out of one end of a syringe-type tube in precise quantities for the patient to collect and ingest. Pros: Precise and adjustable. Cons: Heavy, and restricted to a single analgesic.

• Soap dispenser type pump: Patient would manually depress pump head. Pros: Cheap and easy to use. Cons: Heavy and Imprecise.Strip Tablet Dispenser:

Sheet Dispenser:

• It would dispense analgesic strips similar to Listerine strips. Would function like a modified paper towel dispenser, where every time a button is pushed, one sheet is dispensed. Pros: Dose size adjustable. Cons: Too complex, requires analgesic strips similar to Listerine strips.

Solid Pill Dispenser

• Rotating Dispenser: A wheel with prepackaged strips of pills in blisters would dispense them by rotating and cutting at a pre-perforated line. Pros: Ease of use Cons: Large and hard to design.

• Stack Dispenser: Would be composed of several individual tubes, each with a stack of pills or pill containers. The bottom item of the stack would be dispensed laterally, and the rest of the stack would move down. Pros: simplicity, dose-holding capacity, affordability, variety of analgesics. Cons: limited adjustability of dose size.

Slide One: Specifications

To design the device, we had to address a series of specifications, for manufacturing companies as well as for physicians; i.e. say what we wanted our device to accomplish. These are some of the most important ideas we discussed:

• Intended users: responsible adults and teenagers who are in pain and are deemed capable of controlling their dosing.

• Functions and performance: dispense individual doses of analgesic upon request until a lockout time is reached, an emergency dose available and data storage.

• Ease of use: very intuitive, featuring an LCD screen and few buttons, so that patients would push a single button to request a dose, and then confirm their decision.

• Dimensions: 20x12x10cm, the weight would be under 5.5lbs(2.49kg); the LCD would be 9x7cm.

• Operating conditions: it should be exposable to the sun, water resistant to a point, allow very high/low temperatures, pressures and other conditions.

• Battery life: the battery should be long-lasting (at least 24h) and able to be plugged in to recharge.

• Cost: it should cost under $400 to manufacture.

• Lifetime: the device should have at least a 2-year life cycle.

• Maintenance and repair: the only maintenance required should be charging it and refilling the pills. Repairing the battery and springs by professionals every so often would yield a longer life cycle.

• Reliability and safety: should include a system so that only the patient can take the pills, a lock accessible only to physicians and pharmacists, a lockout time and emergency dose available. It should also inform the patient how many doses are left, and a code to activate refilling.

• Ergonomics and appearance: it should be attachable to an IV pole, have no sharp edges and include a slide-out tray to allow patients to remove the pills easily.

• Disposal: available only to hospitals and health-care centers for distribution to patients.

Detail Design

During the Detail Design week we determined the exact details that were left unfinished during the specifications process. For example, we created size and weight estimates: The device will be 20cm by 12 cm by 10 cm, enough to hold 4 rows of 5 tubes each, each tube 20cm tall and capable of holding 10 cubic 2cm boxes in a stack. This was the ideal set of dimensions for minimizing size while setting aside enough space for the pills and taking into consideration the limits of the constant force spring's extension. In this manner, we also determined in detail all other aspects of the device, like weight and cost.

We finalized the reloading mechanism as well. It was decided that magnets below each constant force spring and an electromagnet that could be turned on and off could be used for reloading. When the physician presses the reload button and enters the necessary code, the electromagnet will activate, attracting all the bar magnets to unwind all the springs. The physician can then unlock, open, and reload the device. When done, the physician can again press the reload button to deactivate the electromagnet.

Since last week, we changed our minds about the cell-phone like sliding technology due to the size and bulk of the device.

Finalizing Specification

During last Thursday’s BE100 recitation DuckHunt design crew (Annie Conde, Anand Sundaram, and Daniel Chabolla) met to finalize the specification of the Patient-Controlled Oral Analgesia Device. Before moving any further with our design it was necessary to create specifications for the three feasible models that had been thought of during our first meeting session. Each member in our group was assigned one of the three models and became responsible for creating specifications for one particular device. After going over the specifications of the three devices and analyzing the pros and cons of each model, we decided that rather than settle for one of the three concepts, it would be wiser to bring together the best features of every device and craft a more efficient, functional, and stylish device.

Final specifications such as weight and size of the model haven't been determined just yet. At the moment, the DuckHunt crew is devising how to stack up and deliver the dosage in the most efficient manner. As foretold by Anand, it is very likely that the medication delivery system will function very similar to the way a stapler operates. The idea is that a spring will be compressing prepackaged doses of medication. The packages will be stacked vertically. At the opposite end of the compressing spring will be a motorized spring that will be extricating the prepackaged doses from their stacked up arrangement. We have yet to determine how we will refill the device; something that is likely to be determined during our next session. You can bet, though, that our device will have cell-phone slider technology and will be displaying an LCD screen.

Conceptualizing

Before we begin to design anything, we need to brainstorm three conceptually different conceptual designs for a patient-controlled oral analgesic device. During Thursday's recitation, we came up with two viable concepts. One was a Pez-dispenser-like assembly line pill dispenser that could possibly function like a stapler (when you staple something, all the staples move down; similarly, all the pills would moved own in our device). The second was a liquid analgesic dispenser along the lines of a liquid hand soap dispenser. The main issue to be solved for both of these designs is security - how can one lock a patient out of using a soap dispenser? We need to design some mechanism to control the dispensation of analgesics in for both types of device.

We still need to come up with a third design concept. This should occur early next week. On Thursday, we cycled through several ideas only to dismiss them one by one. The one that generated the most conversation was the idea of making analgesics like Listerine strips, which would certainly look pretty cool.

Cheer up and check out some PEZ:
http://www.pez.com/v/default1.htm