Discussion

As manufacturing began, unforseen complications led to alterations in the original design and budget. Below are the details of those changes and how they effected the final product.  

Compartment Lids 

One of the first roadblocks encountered while building the initial prototype was the bent lid with music wire inserted. 

The bending of the plastic was less uniform than was expected. Using the heat gun to bend the plastic gave uneven bending and unreliable results. Using an oven to heat the pastic showed that the material would bubble internally. As it turned out, in order to bend the polycarbonate by heating, it meant that the plastic had to go through a two hour drying process. We didn’t have the means or time to address this issue. The music wire was also removed form the design because it would’ve been difficult to insert through the plastic at the right position because the available machinery was unable to grip the lids and make the precision hole required to place it. 

The two part lid solved this issue. It could be uniformly and cheaply made. Adding the screws meant cheaper and simpler production as well as a a lid opening force that was adjustable. The screws can the unscrewed slightly for better and therefore stronger contact with the two magnets or screwed deeper into the plastic which lessens the attractive force to the magnets. This also gave an improved solution to the tab needed to grip and open the lids without the requirement of fine motor skills by the user.

Hinge 

Another issue encountered was the Nylon fabric hinge with rivets. The fabric would fray when any hole is punched through it. When we added glue to the fabric, the fraying wouldn’t happen. However, once the rivet was put through the hole of the fabric and the hole of the lid, it would disfigure the fabric so that it wouldn’t lie flat and it allowed to the lid to twist and not activate the sensor.

To address this issue, the nylon hinges were replaced with brass hinges with brass plated steel screws. This eliminated the poor look and non-uniformity of the fabric and reduced the twisting of the lid relative to the plastic it is mounted to.

Cost Breakdown

Magnetic Latching System

In order to eliminate the twisting of the compartment lids the final design add an extra .8 lb force cyclindrical Neobydium magnet to the existing 2.5 lb magnet. The one magnet on the side of the sensor wasn’t enough to bring the lid down to rest flat against the plastic surface and compress the plunger of the sensor. The second magnet worked to overcome the moment caused by the plunger.

Cost Breakdown

Dimensions

Another change that had to be made was increasing the overall dimensions of the device from 11.25" x 4" x 10.5" to 12.75" x 5" x 10.5". Each step of the device where the pill cups are held increased by 1/4 inch in height and depth. This was decided on after completing the initial prototype. It was found that more room was needed for the LED lights with their mounts to fit in the vertical plates behind the pill cups. This also allowed for greated amount of the cup to sit out of the holes for easier retrieval. The higher up the cups sit in the plastic, the smaller the diameter hole in the plastic for the cup. Originally, the pill cups would hit the edge of the opened lid during pill retrieval. The added depth of the step removed this issue. This change resulted in an extra $25 if HDPE being purchased to rebuild the device structure.

Sound Alert System

In order to achieve the volume requirement shown in the Device Specifications, the chosen sound system required the addition of an amplifier.

Cost Breakdown