This sensory design is a project designed for a little boy diagnosed with cerebral palsy. He loves music and flashing lights, but he has minimal ability to use his limbs. His eyesight is also limited, and the idea is to have bigger buttons for him to be able to press to activate a song or light. His adoptive family’s desire is to have buttons that play music, light up, and say yes and no to help him learn how to communicate.
The sensory box will involve Noah’s strength and muscle coordination as well as work to develop the prefrontal cortex through physical interaction. Through the function of intractable buttons and switches Noah can connect physical movements with neural connections to help develop problem-solving, planning, and regulate emotions.
Design Specifications: After talking with the family and getting some suggestions of features they would find useful we have concluded that we will need these features to accommodate the family.
• Yes/No button to help communication
• Locking mechanism to highchair and/or wheelchair
• Can be used laying in the floor
• Sound/song buttons for entertainment
On the market, there are products that provide sensory adaptive toys for kids. Most of the products are single function toys that are repetitive and only play the same couple seconds of a song. There are some button/switches that are easily activated and safe.
We are trying to provide a product that allows ours to be personalized and provide lots of different uses.
Our first design incorporates the use of 3 foam sensor to provide padding for his hand when activating the sensor. It is also at an angle to provide room for wiring as well as creating an angle so it is easier to activate. This design would also be modified to fit into Noah’s high chair and be able to be stationary on the ground.
For our second design concept, our group decided that it would be a good idea to possibly collaborate with the group that was in charge of building the supportive chair for our child. Therefore, this design was sort of based upon the idea of building a collaborative table that could be locked into the supportive chair while having the ability to be removed and placed wherever is easily accessible. This design would include a variety of sensory driven button and switches specific to what he liked.
For our third design concept, we designed a rectangular box that would be made of plastic with a rubber lining. This box would have distinct functions based on which side was front facing at the time with some features including but not limited to, buttons to indicate yes and no responses, reprogrammable buttons to play music, sensory switches that light up and make noise, and manual cutoff controls to regulate accidental activation.
After conducting our decision matrix, it led us to selecting Concept Design 1. Although this is the selected design, it is likely that our final design will include aspects from each concept design.
Our selected design incorporates pieces of each of our concept designs 1, 2, and 3.
In the first phases of our design process, we wanted to consider several things: price, size, rigidity, and, of course, the recommendations from the family. One of the things the family recommended was that they preferred the toy to be mobile and of a size that could be used on the floor and also in a tray on the child’s seat where he spends his time doing daily activities. After receiving the dimensions of the tray, we were able to come up with a size that we believe will best fit the tray and also transition to the floor easily. Once we developed some overall dimensions, we were ready to choose the material. Although there are numerous materials that could fit this project well, we decided to choose 3 different ones (aluminum, MDF particle board, or acrylic) and allow our shop manager to give us his opinion on which one he thought was best. After getting his opinion, we decided that the best option was aluminum because it is cheaper, more convenient, and more rigid. Although this material will have its downfalls, we believe we can overcome most of these downfalls by adding features to make it safer and more accessible for our child to play with. For example, we plan to add a padded material to the outer surface of the toy to eliminate any dangerous hazards this material could possibly cause. We also plan to add a rubberized material to the base of the toy to help keep the toy stationary as much as possible.
After completing our mechanical design process, we moved into the electrical side of things. We plan to use an Arduino Micro without headers and connect a 9V battery source from a 6 AA container. This will give us a consistent power source to run the buttons soldered to the Arduino as well as the 3 Watt 8 Ohm speakers and Micro SD card reader. All of these components will be soldered directly to the board and then housed inside the box to prevent any damage while still providing accessibility to change or recharge batteries.
Considering our project at hand, one of our main goals was to consider the weight of our toy. We wanted to make sure our design wasn’t too heavy for our child’s family to move around when needed, but to also make sure it wasn’t too light that it could be easily manipulated while he was playing with it. Using our 3D modeling software, we were able to find our weight force which is also calculated in the image of the free body diagram provided.
For our second analysis, we did some research on the typical force required to push a simple mechanical button. We found this to be approximately 2-3 pounds of force. Although this force may or may not be true to our application, this generalized analysis gave us a total resultant force of 10.44 lbf that pushes at an angle of 19 degrees into the ground.
Our last analysis shows us exactly how much force would be required to move the toy on typical dry wood surface (i.e. wood floor). We calculated this force by using our knowledge of dynamics along with some research to find the appropriate friction coefficient for this case. Accounting for the weight force of the toy and the friction force acting against the pushing force, we found that the pushing force would have to be larger than 8.26 lbf in order to set the object in motion. As a team, we believe this achieves our goal of allowing the child play with the toy in any position without easily manipulating it.