From the offset, our Micro Mouse was designed with sustainability and recyclability in mind. We knew that even from a practical viewpoint, our project would be a constantly developing item that likely wouldn’t end up like we imagined when we first assembled the chasse. We therefore ensured all aspects of the design were able to be easily disassembled and re crafted. Practicality aside, it is clearly essential that experimental projects and commercial products alike need to have sustainability at the heart of design; we therefore explored what design choices we could make that would allow us to completely strip and either reassemble our Micro Mouse or recycle the components for others, leaving as little unusable hardware left as possible.
Chiefly we agreed that all connections were usable serviceable, this means no soldered connections between hardware, only screw terminals or jumper cables, the exception being the seesaw board which I will discuss below. We also incorporated this into larger parts of our PCB; hardware such as the five ultrasonic sensors and IR receivers were also mounted in sockets to ensure that this hardware can be easily reused. Furthermore, our PCB design focused on user serviceability and recyclability by ensuring it can be easily disconnected from the control board. All connections for both IR and Ultrasonics pass through one bus with shared power between the two circuits, also cutting down on unnecessary daughter boards and wiring.
As well as this, we came up with a solution to cut down on structural hardware. Our two boards, or, ‘slices’, as we came to call them, the control and IR/Ultrasonic boards, are connected together and then to the chasse ‘slice’ with two central pillars that bolt together with through holes in the slices. This allows for easy disassembly and greatly reduces unnecessary hardware, as well as greatly reducing the profile of our mouse, saving on 3D printer filament for the shell.
When it comes to recycling our project, most components can come out just as usable as when they went in. the ultrasonic and IR sensors are simply removed from their sockets, the same with the display and motors. The central pillars are simply screwed together, the power switch is connected with a single bolt, as are the white line sensors.
In terms of non-recyclable components, chief among them is the PCB stripped of sensors. This double-sided design did add to production complexity but saved overall on the hardware needed to incorporate our sensors. As with all PCBs they are exceedingly complicated to recycle, another reason we tried to fit as much as possible on it and not on daughter boards that add to waste. Our white line sensors did have to be located on perf board underneath the chasse slice. Our original plan was to incorporate these onto the PCB along with the seesaw used to control them. We would have used the PCB as the chasse slice, mounting the motors too it, and removing the unnecessary chasse board. This would further reduce our profile and allow for the seesaw to be reused as this too could be socketed, its I2C connection passing through the central bus. Time and complexity however got in the way of this but for future iterations, this would be a good step towards further reducing unnecessary hardware.
Thomas Hobbs 2114555
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