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Project 12: Sensory Bed

Abstract

The goal of our project is to design and assemble a sensory bed that will allow the child to have a safe and calming environment to relax. The sensory bed will assist the child in handling overstimulation.

Steven Sugg, Luke Collins, Ethan Haynes, Baron Marshall, Shantini West

Problem Statement

During the fall semester of 2023, we five students in Dr. Canfield’s ME 3610 course at Tennessee Tech hope to improve the life of a local Cookville child who has difficulties with overstimulation and feeling safe in a sleep setting. We aim to fix this issue by designing and constructing a Sensory Bed with Black Out Curtains so the child can have a safe place to relax.

Design Specifications

– Keep at temperature range of 65 °F to 70 °F, include a fan
– Calming LED lights on interior (twinkle lights), but be able to be completely dark.
– Bed frame has to be flat on the ground. (No legs)
– Minnie Mouse themed
– Include a safety railing
– Be fully enclosed with a cloth canopy
– Have a zip-open window and doors
– The child should be able to fully stand-up inside
– Be fully portable
– Prefers soft textures
– Have a fully adjustable tablet stand that locks into place
– Has pica, use blankets to cover all solid accessible materials.

Background Research

For the heating and cooling element of our design, Steven consulted Dr. Ahmed Abounassif about how to get the ideal temperature of the bed through heat transfer.

For the fan, we decided to use an HG Power 4 Inch Inline Duct Fan due to its compact size high performance, and low noise output.

For the material we would like to use for the blackout curtains we have decided on Kevlar due to its low thermal conductivity and it being very difficult to tear or rip.

For the structural integrity of the bed frame, Ethan is consulting Dr. Sally Pardue about how to prevent buckling and displacement when a force is applied to various parts of the bed frame.

We looked at an example of an overhanging umbrella for Concept Idea 1, a folding canopy for Concept Design 2 and a mesh enclosure for Concept Design 3.

 

Concept Design 1

Pros:

  • Easy to Build
  • Lightweight
  • Cheapest

 

Cons:

  • Susceptible to falling
  • Poor Ventilation

Concept Design 2

Pros:

  • Structurally
  • Great Ventilation
  • Meets most Criteria

 

Cons:

  • Expensive
  • Top Heavy

Concept Design 3

Pros:

  • Safest
  • Meets all Criteria
  • Has extra storage space
  • Good Ventilation

 

Cons:

  • Expensive
  • Heavy

Selected Concept Design

We chose design 3 as it met the most constraints and added more features to the benefit of the child and family. The design of concept 3 is child safe as there are no rough edges compared to design concept 1 or 2.

Decision Matrix

Overview of Selected Design

We chose to combine design 1 and 3 due to recommendation from our professor. We chose to build our own frame rather than ordering one online due to our unique design specifications and to limit the cost. We are using a steel frame with aluminum supports and a cloth canopy attached to the hook on the bed frame. The bed will include a tablet holder, lights as well as a cooling system to ensure the child is comfortable. One side of the bed will have a detachable metal bed rail to prevent the child from falling out, as the other side will be against a wall.

Describe Design Details

Bedframe:
For the bedframe we chose to go with steel due to its low cost and high strength. This will ensure that the frame will be sustainable enough for any additions to the frame and very difficult to topple.

Tent:
For the tent we decided to use a polyester material to reduce light exposure inside the tent, Allowing for better light adjustment inside the tent which will help with the light sensitivity of the child.

Pole and Hook:
The pole was chosen to be made out of aluminum as it will not have any major stress applied to it other than the tent. The hook however, is made out of steel as it will be cheaper to requisition a steel hook rather than an aluminum one.

 

Lights:

We chose to use Fibre optic cables woven into blackout fabric to mimic fairy lights. Combined with a mesh underlay to ensure the child will not be able to rip out the cables and a Minnie Mouse overlay for the overall Minnie Mouse theme.

Engineering Analysis 1

We used the simulation feature in SolidWorks to generate stress and displacement analysis of various features on our final model. For our first simulation, we chose to do the hook because it has to support the canopy and lights. During the simulation, we simulated what would happen when twenty-five pounds per foot force was added to the hook. After the simulation was completed, we saw that the stress was primarily focused at the top of the arc and displacement was at the hook.

Engineering Analysis 2

We used the simulation feature in SolidWorks to generate stress and displacement analysis of various features on our final model. For our second analysis, we chose the railing on the bed frame because the main purpose of the railing is to prevent the child from falling out of the bed while they are asleep. We decided to simulate what would happen when fifteen pounds per foot force was applied to the railing. After the simulation was completed, we analyzed that the displacement was focused in the center of the railing. While the stress was evenly distributed into the bed frame itself.

Engineering Analysis 3

Using ANSYS Fluent we computed the theroretical flow rate. I assumed a large body assumption for the bed since it is so much larger than the pipe volume. In this analysis we computed the temperature from the flow of a fan going .675 m/s. The speed was calculated from the flow rate and surface area of the provided specs. The overall analysis concluded that 0.5in holes are adequate to allow proper flow into the bed environment.

CAD Drawings

Document Fabrication Process

To fabricate the bed there are three major components that need to be manufactured.
1.Manufacturing the bed frame.

A. Obtain steel frame and PVC pipe

B. Powder coat the bed frame and paint the PVC

C. Weld the steel frame together and assemble the PVC                      overhang.

2.Manufacturing the Cooling unit

A. Obtain thermo electric cooler due to low noise

B. Assemble copper pipes to obtain satisfactory heat                       transfer to the ambient air in the bed.

C. Ensure there are no air leaks when connecting the fan               and to the PVC air transfer pipe.

3. Manufacturing the Canopy.

A. Obtain the needed fabric such as display fabric, black out fabric, and mesh to cover the Fiber optic cables.

B. Sew the three layers together.

C. Install fiberoptic cables with LEDs

 

Testing Results

During testing we deemed the structural supports for the canopy was insufficient so we added three additional support beams to ensure no failure would occur. We also deemed the airflow for the cooling unit to be lower than expected.

Completed Design Photos

Instructions for Safe Use

Go into the canopy and enjoy!

Project Summary/Reflection

Overall this project was a great way to expand the groups understanding of what needs a child with Pica has. We endured many challenges yet continued to push forward together as a group and ended up with a great product for a great family. With Shan’s tireless work on the canopy, Ethan’s amazing job on the frame, Baron assisting with just about everything, and Steven working on the cooling unit it came together just in time! We are very proud to have made this project a reality bringing joy and a safe space for a wonderful kid.

 

Link to YouTube video:

 

Semester

2023 Fall