Senior Capstone Project - Circadian Shades
For a more concise summary of our project, please click this link
Background:
People with Circadian Rhythm Disorder often find it challenging to fall asleep and wake up on a natural sleeping cycle. People with Circadian Rhythm Disorder require a completely dark environment to fall asleep and a natural bright environment to wake up. The current demand is for a less expensive product that can create a fully dark environment for sleep. This product will improve quality of life for those suffering from Circadian Rhythm Disorder. Finally, this product is also viable for people with normal sleep cycles that prefer a dark environment and waking up to natural light.
Design Objectives:
The main goal of this project is to create an automatic opening window shade to combat the effects of Circadian Rhythm Disorder at a low cost to consumers. The product needs to be robust and create a completely dark bedroom environment for the consumer.
My Role and skills demonstrated in this project:
Main Design Goals:
We developed three potential designs, one of which is the most functional. The difference in designs was the way energy was stored.
The first being a counterweight system. However, this design was not chosen since reloading the counterweight after each use will be challenging to automate and may require the end user to pull the shade manually.
Another design considered is utilizing a power screw to roll the shade up and down. However, one drawback from this design is that the shade cannot be deployed down at intermediate heights. The latch-locking mechanism would only engage when the shade was fully deployed which would limit the versatility of the design. The long linear motion of the spring and subsequent rotation of the power screw would require lubrication and potentially periodic maintenance.The final design considered includes a blackout shade that unravels from a spool. Inside the spool, a torsion spring and damper is attached to the spool that acts as a the power source to bring the shade up. When the shade is pulled down, the spring stores potential energy that is later utilized to rotate the housing tube and raise the shade. This design proves to be much better than other designs since not only does it create a completely blackout environment by extending all the way, but also would require a lot less work from the consumer.
Thus, we chose our final design that involves a spool.
Internal Design of the Shade:
Background:
People with Circadian Rhythm Disorder often find it challenging to fall asleep and wake up on a natural sleeping cycle. People with Circadian Rhythm Disorder require a completely dark environment to fall asleep and a natural bright environment to wake up. The current demand is for a less expensive product that can create a fully dark environment for sleep. This product will improve quality of life for those suffering from Circadian Rhythm Disorder. Finally, this product is also viable for people with normal sleep cycles that prefer a dark environment and waking up to natural light.
Design Objectives:
The main goal of this project is to create an automatic opening window shade to combat the effects of Circadian Rhythm Disorder at a low cost to consumers. The product needs to be robust and create a completely dark bedroom environment for the consumer.
My Role and skills demonstrated in this project:
- Brainstorming and concept ideation
- Initial Calculations
- Component assembly/component interface CAD
- Prototyping and machining of parts of the shades
- Rapid Prototyping (ABS and SLS 3-D printing)
- Conduct FEA analysis on parts made
- Final presentation poster
- Final report and presentation
- Project management and communication
Main Design Goals:
- Low Cost
- Creates a blackout environment by blocking sunlight
- Passive (Timer-based semi-automatic opening)
- Silent when unraveling
We developed three potential designs, one of which is the most functional. The difference in designs was the way energy was stored.
The first being a counterweight system. However, this design was not chosen since reloading the counterweight after each use will be challenging to automate and may require the end user to pull the shade manually.
Another design considered is utilizing a power screw to roll the shade up and down. However, one drawback from this design is that the shade cannot be deployed down at intermediate heights. The latch-locking mechanism would only engage when the shade was fully deployed which would limit the versatility of the design. The long linear motion of the spring and subsequent rotation of the power screw would require lubrication and potentially periodic maintenance.The final design considered includes a blackout shade that unravels from a spool. Inside the spool, a torsion spring and damper is attached to the spool that acts as a the power source to bring the shade up. When the shade is pulled down, the spring stores potential energy that is later utilized to rotate the housing tube and raise the shade. This design proves to be much better than other designs since not only does it create a completely blackout environment by extending all the way, but also would require a lot less work from the consumer.
Thus, we chose our final design that involves a spool.
Internal Design of the Shade:
Each part contributes to one of three key design aspects including, creating a blackout bedroom environment, providing autonomous power, and a timed opening mechanism. As discussed in the background section, creating a blackout environment is vital for this products target market. The material being used allows little to no light to pass through by utilizing a vinyl backing with a tight weave black fabric exterior. To test the validity of this material a bright flash light was placed directly behind the fabric to see if light would pass through. After testing the fabric was validated and put into use.
The torsion spring was custom made through a set of parameters detailed in the design. The torsion spring was mounted with a dowel through the center to provide and anchor point to build spring potential energy. To apply the energy to the shade, the rotation block was mounted to the free end of the spring. This rotation block was design to fit inside the aluminum tube and apply rotational force through the notch shown. This design idea was derived from how a manual pull down projector screen works. When pulled down the torsion spring builds energy that can be applied to roll the shade up when desired.
The final key design component is the timed opening mechanism. The shade has a ratchet gear attached to one end which rotates freely with the shade when pulled down, but is impeded in its motion by a pawl when the shade starts to move up. This mechanism will hold the shade closed, but can be opened from the control system which utilizes wireless connection to the user’s cell phone over the Wi-Fi network. Before going to sleep, the user will close the shade, and set the timer for the desired amount of sleep time. When the timer hits zero, the phone will notify the Raspberry Pi board on the blind that activates the servo motor to rotate the pawl out of the position that impedes the ratchet gear. This creates a freely rotating shade which can rise to let sunlight into the room and wake the user. Additionally, the user will be able to open the shade at any point without setting a timer by pressing an override button on their phone.
The key decisions that went into choosing the torsion spring design centered on the simplicity of the build. All three initial design ideas incorporated a stopper mechanism similar to the servo motor activated pawl in the torsion spring design, so that was not a key factor in the decision making process to start. With the torsion spring idea, it was extremely easy to house the energy inside the tube. This makes it difficult for the consumer to come in contact with the spring and potentially injure themselves.