We sought to create a light regulation system for our garden. Sunlight is incredibly important to plant growth, and a carefully executed regulation system is necessary. We wanted to create an environment that could be completely controlled regardless of the natural light conditions on Mars. The system is dependent on the conditions recorded by the light sensors, so it will continue to function as long as it has power
We created a series of three panels controlled by servo motors that are able to close and open to block or allow light. The structure holding up these panels is also lined with LED strips that can increase the level of light, especially in a wavelength that is most conducive to plant growth. The system is controlled through a Raspberry Pi, either manually from a remote computer or determined by readings taken from a luminosity sensor. The structure and panels are made from a combination of wood and chipboard.
The domed shape of the structure was determined by design proposed by the Building an Atmosphere class. The basic idea of controllable blinds was taken from the environment created in the Intelligent Workplace. Their system is controlled by sensors but can also be overridden by people using the space. This reflected what we wanted our Mars habitat to accomplish
The panels were designed so that they could be controlled by servos at one edge and freely rotate within the structure at the other edge. The axis of rotation is along the center of the panel in order to allow the system to use its space most efficiently. A rotating design rather than an unfolding design was chosen for the apertures in order to keep the mechanics simple and less likely to jam and fail, which is an important factor to consider in the martian environment. The basic idea of two “spines,” one housing the servos and one allowing for free rotation, remained consistent throughout the design process. Several different methods of keeping these two spines attached were attempted in order to interfere minimally with the movement of the panels and keep the structure solid. The code to control the habitat was written so that it could be easily controlled with simple commands and so that the operation of the prototype could be easily demonstrated in class.
The project made us think a lot about feasibility and sizing. While the panel rotation makes sense for mechanical simplicity, it takes up a lot of space when in open position. This could be solved by making a series of thinner panels and more motors. Our servos were not rotating smoothly when they were controlled. The jitter could be from the power supply that we used to power the servos. The Luminosity sensor was difficult to calibrate, and values would flatline if the light intensity increased past specific threshold, so we should make sure we pick sensors that will work best in the Martian atmosphere. Wires can get messy really fast. In the future looking at wireless components could help give us more freedom as to where we want to place certain things. Ideally, we would want to make sure that the wiring doesn’t affect sensitive components that could be affected by propagation delays. Also, wires could affect with the physical layout of the habitat, since they would need to be concealed and routed throughout the structure. Lastly, wires take away from our available weight.