Automating the Bedroom Window

^{Master Doc.}

(Draft in progress; please contribute)

Goal: 

Fully or partially automate the raise/lower of the bedroom read window that's positioned behind the bed. If only partially lowered, consider adding a thicker strip to the top of the window to serve as a sort of railing.

Challenges:

• Window is approximately 80 kg
• Window has an arclength (overall length) of 6 meters which potentially leads to large overhang moments
• Blending 3D contour of Seapod shell with 2D contour of window. 
• Sealing from the elements and not compromising R value
• Hiding components allowing access
• Automating affordably, ideally with off-the-shelf products

Finalized Hybrid Concept:

Partslist found here.

The system consists of 3 main components:

• 6 meter curved polycarbonate window
• Counterweighted guide rails
• Lift mechanisms

The counterweighted guide rails are there to hold the window from the sides and restrict its movement to one degree of freedom. This system is modeled using aluminum extrusion as a support structure. An off-the-shelf linear guide with two carriages (e.g.) is used to guide the window up and down, while restricting all other degrees of freedom. Note, linear guides may require periodic lubrication depending on which are sourced. The system is counterweighted by a Ø100 mm x 500 mm cylinder of steel (approximately 31 kg). Pulleys and 1/4" nylon rope are used to connect the window through a hole in the aluminum to the otherside where the counterweight hangs. Eyebolts and rope thimbles can be used to connect the different elements. 3D printed pulleys may prove sufficient, otherwise brass pulleys can also be sourced off the shelf. 

The lifting mechanisms have been placed in line with the center of gravity of the window. This lands roughly 1.5 meters from the center of gravity for a total of 3 m between lifting mechanisms (See option 2 in the plan-view diagram in the below section). If it turns out more power/support is needed, a 3rd lifting mechanism could be added behind the headboard in the center. Luckily, because of the counterweights, these lifting mechanisms will theoretically not see much force. That being said, they will feel some overhang forces from the window hanging out so far. The lifting mechanisms should therefore be of the type that they will hold position even when not electrified. This will help support the window and improve the function/reliability of the linear guides used on the ends. This is how we get away with cheaper linear guides rather than the expensive ones that must resist all of the loads on there own (see "using only linear actuators on the ends")

For now, these have been drawn as linear actuators. This has been done for ease of drawing and perhaps implementation, but we have also discussed using motors/pulleys in place of these linear actuators. Even traditional car window openers have been considered. This would work so long as the 650 mm stroke can be matched, the lift mechanisms could be synchronized and hold  position when off. Physical experimentation will help determine the best mechanism. For now, I recommend buying both options since they are so cheap (car window opener e.g; track linear actuator e.g.) and at worst, could come in handy elsewhere.

The window is designed to travel 650 mm up/down. This does not lower the window entirely, which is actually ideal from a safety standpoint. The window can serve as a sort of guard-rail when lowered. 

To this end, we have designed a round piece of polycarbonate to fit atop the topside of the polycarb. window. This could be fused via ultrasonic welding. This round element will also make sealing the top of the window when its closed easy.

April 13th Updated images below

For older concepts and scratch work, head here.