We were asked to make a sensory bed that helps a 2 year old sleep at night securely, and has features including a circadian lighting system, a speaker that plays soothing sounds, a camera to monitor him at night, and a secure enclosure without exposed wiring for him to pull at. The bed also needs to be built sturdily, as the kid is very active and strong for his age.
We need to design a bed that safely contains a child who is prone to wake up at night and wander. The bed also should have technologies in place to help the child get a full night’s sleep. The family has communicated that they want peace of mind, knowing that their child isn’t wandering around the house if he wakes up before the rest of the family. The child is also very active and strong for his age, so the bed needs to be able to withstand lots of abuse. Any electronics need to be secured such that they can’t be pulled at or disturbed by a child. The bed needs to fit the child now, at 2 years old, up until he is old enough to no longer need it. With these goals met, the parents will have peace of mind knowing that their child isn’t up and going where he shouldn’t be.
The bed needs to be able to be in use for as long as the child will be restless during the night, so it needs to be large and built well to last that long. The frame needs to be very sturdy so that the child will not break it by jumping on it or pushing it. The bed needs to fit a full sized mattress. The sides need to be see-through so that the parents can check in on the child, and the sides must also be breathable. There needs to be easy zipper access to the bed that is also secure so that it can only be unzipped from the outside. There must be some sort of lighting system that can simulate a sunrise to reinforce good sleeping habits. There must be a speaker that can play white noise, and preferably, also play audio from a wireless device. There must be a camera system to monitor the child, with 2 way communication as a possible extra feature. Where possible, make the bed safe to bump into – avoid hard edges and exposed metal.
The family sent us pictures of a commercial safety bed that had many of the features they wanted, so we had a good starting point for our research. We looked at other safety beds and enclosures commercially available to get ideas for common design guides and possible features to implement. In our research, we found tents available from web retailers that can be mounted to an existing frame, while having many of the features we already want. However, these tents seem too flimsy for the type of abuse we expect this bed to take.
Pictures:
Notice the bed’s dimensions represent a full size frame. The speaker and light are on the headboard for maximum closeness to the child. The camera is on the far side of the bed for a full view and blackout curtains are on the outside so the child can’t reach.
This design uses a wooden rectangular box frame with a wooden A pillar frame on top. The box frame is enclosed with a fine see through mesh on each side and top, with a zipper door on one side. The zipper is only accessible from the outside, to prevent the child from being able to leave their bed during the night. There will also be blackout curtains on each end to limit light passing through. On the interior of each post on the frame, there will be a foam board at an angle to provide protection and prevent injury. The A pillar section will be open, having a blackout curtain on top which can be draped over each side. This section will also include a light bar, speaker, and camera to allow the parents custom control over the interior environment. This design allows for the separation of the electrical components from the sleeping area, ensuring a safe sleeping environment, while also not interfering with camera visibility.
3 was selected as the final selected design on the decision matrix. It has the sturdiest build, and it incorporates a dedicated space for the electronics that is out of reach for the child. For the final design, we adjusted the a-frame at the top of the bed to be shorter, as the original design had an excessively large frame. We also changed board sizes to better fit commonly available wood sizes. The electronics were added to the model to approximate their final locations.
Or design is one that is able to accommodate all the feature needs of the family who requested it, while having the durability and reparability to last for many years of the child’s development.
The backbone of the design is the frame. It needs to be able to fit a full size mattress that the child can grow into. In addition, it needs to be overbuilt, as the child is very active. The frame must be able to support the mesh sides and top, and contain mounting points for the mesh. It must also have places to mount the electronics while keeping them out of reach for young children. Finally, the frame must be safe for children to interact with, having soft edges, no splinters, and nontoxic paint.
Next, the mesh sizes are what transform this bed from ordinary bed to security bed. They must be strong enough to withstand a child leaning back against them, while being breathable and see-through. There must be a door in the front of the bed that allows for parental access while keeping the child secure. It is preferred that the mesh is easily replaced in the event of a tear or similar compromise to its integrity.
Finally, the electronics are the bow on top, giving the parents more peace of mind and making the experience better for the child. The 3 essential components are a speaker for white noise, circadian lights, and a camera. The speaker is part of the design so that it can play sleep-aiding white noise. Bluetooth connection is a nice-to-have, but not a strict requirement. The circadian lights have a similar sleep aiding function, where the light turns on automatically in the morning to simulate a natural sunrise. Another nice-to-have is toggleable interior lights separate from the circadian lights. The final electronic component is a camera that allows for monitoring of the bed, as well as two way communication. All of these electronics must be safely tucked away so that they cannot be tampered with or pulled at by the child.
The Calculated worst-case stress was around 16.66 Psi. This value is way lower than the maximum critical stress, according to the Engineered Wood Association. The assumption of 750 pounds should accommodate any need that the bed required for the child well into adulthood. This analysis accounts for material safety and any loading conditions that the bed frame may be put under.
The calculated worst-case tension in the mesh was approximately 325 lb, which is significantly lower than the estimated tensile capacity of the mesh material (about 700 lb per inch of width). This indicates that the mesh operates well within its allowable strength limits. Additionally, the assumed design load of 975 lb, which includes a safety factor applied to the estimated 360 lb impact load from a 120-lb user, provides a substantial margin of safety. This design load should accommodate expected loading conditions such as leaning or accidental impact against the mesh.
This analysis focuses on the electrical components. The attached image is an analysis of the power limits for the electrical components, ensuring that the devices will not surpass the power strip limits or wall outlet limits. It is also more important to note that the power strip has surge protection. There are no exposed wires in our design, so there is no shock hazard there.
Fabrication occurred in 4 distinct steps: frame, mesh, appearance, and electronics.
Fabrication consisted of us cutting wood, measuring, and making sure the frame of the bed came together how we intended it to. No surprises here, just some carpentry.
While attaching the mesh, we discovered that we needed to put tension on it during install so that it could effectively enclose the occupant. Typically, we would have 3 people pulling on a mesh section while the fourth would drill in the wood block we used to restrain the mesh.
After initial assembly, we took the bed apart to and and paint all the wood pieced to make it look presentable, while also ensuring a splinter-free finish.
The electronics portion was the easiest, we just found places to mount the devices to keep them out of reach for the kids but serviceable by the adults.
We built this bed to be rock solid, and it delivered magnificently on this goal. At times during assembly, all four of us would stand on the bed without worry we would break something. You can see us hanging from the top boards in some of the pictures. The mesh was also very strong, as it allowed us to lean our full weight against it without tearing.
Considering this bed was built for a 2 year old, we have full confidence in it’s durability for many years of use.
We’re very pleased with the final product we were able to deliver to the family. All four of us were dedicated to seeing this project through from the initial design to the final assembly. Some of the challenges we ran into were the logistical challenge of transporting a full size bed an hour away, how to attach the mesh, and where to put the electronics. During the build process, we found solutions to these problems through our teamwork. The mom was super happy to have a safe place for her son at night, and her 3 kids loved the bed. As soon as we finished the build, they jumped in the bed and started playing in it. If we were to do it all again, I don’t think there’s much we would change; maybe some small details would be different, but as a whole, the bed works magnificently. We hope it will serve the family well for years to come.
