Team Members
James Beard, Matthew Giles, Mu He, Janna Iklaas, Jonathan Mitzenmacher, Zihong Ye
Abstract
That Heliostat is a single-unit, modular heliostat equipped with four triangular mirrors whose combined reflective surface area is less than one square meter; it can be controlled wirelessly thanks to a built-in ESP-32 controller. This design is equipped with three stepper motors: one motor to control azimuthal rotation, one for vertical-circular rotation, and one motor to control the inward rotation of the mirrors. The first two motors are housed inside an IP55 rated, 3D-printed cover along with a series of 3D-printed gears configured to prevent motor back-drivability. This cover is fastened to thick PVC piping, which doubles as a support structure and storage for electronic components, press-fitted into a 3D-printed base. Inexpensive, yet durable metal piping is mounted on the sides of the base and sandbags are placed on top of the piping after installation for added stability of the unit. That Heliostat’s mirrors are comprised of a Mylar sheet with a layer of acrylic epoxied on top; this design keeps the Mylar protected while retaining its high reflectivity and is less expensive than traditional mirrors. The heliostat’s total reflective area is divided among four mirrors to decrease wind loads on the unit, thereby improving its environmental resistance. A distinct feature of this design is the additional stepper motor housed in the mirror subassembly, allowing for the inward motion of the mirrors. Thanks to this feature, the concentration ratio can be adjusted independently so the distance at which That Heliostat is placed from the target becomes less problematic