The Start.
Ideation.
SPI Hunter traces its humble origins back to an ideation session hosted the day after we received the project. During this session the team evaluated the requirements of assignment along with the materials/knowledge shared among the team members to determine the project direction.
Initial concepts included a thumb war game/ claw machine/ gadget counter; however, we ultimately decided on a driving game as it met the criteria listed on the matrix we created.
Initial concepts included a thumb war game/ claw machine/ gadget counter; however, we ultimately decided on a driving game as it met the criteria listed on the matrix we created.
Refinement.
After committing to the driving game, the team began refining the fundamental, "How Might We..." questions associated with this project.
- How might we... build this project within the allotted time period
- How might we... make this a fun project with which to interact
In regards to the former we spent time on the basic physical blueprint for the game. Inspired by arcade cabinets of yore, the initial design for SPI Hunter was a sleek and simple box with minimal peripherals. We attempted to maintain this aesthetic throughout the multiple iterations of design.
The latter question necessitated we put a fun spin on the requirements of the project. For instance, to make the analog movement requirement as enjoyable to the user as possible, we opted to provide this input with a big bright steering wheel. This whimsical mindset persisted as we created the basic gameplay loop for our project, which was illustrated in some initial design documents.
As will be seen, not all of these initial concepts were present in the final project (card scanner/ linear progress indicator/ etc); however, this initial design provided enough guidance to begin CAD modeling.
THE MODEL.
Sketches.Prior to designing on the computer, the team utilized rapid prototyping via simple hand drawn sketches. This allowed us to quickly iterate solutions to the two largest problems facing the cabinet.
The latter aesthetic limitation was imposed by the team. As we wanted our machine to resemble a late century arcade cabinet, we avoided the use of visible fasteners; thus, parts had to be designed as puzzle pieces, while still allowing for easy access to components for debugging.
These sketches allowed for quick design/redesign of the slotted sides. As can be seen even the tabs were kept to a minimum (as too many would also detract from the desired look), thus the ease of erasing/redrawing notches on a piece of graph paper made the SOLIDWORKS model far easier to create. |
In regards to the former, the PRL laser cutter can only cut 12" x 24" sheets, thus limiting our maximum component size.
Moreover, as a result of the limited project timeline/budget we knew that all building material would have to be locally sourced. Room 36 thus became our exclusive source of birchwood/acrylic. An initial trip to this supplier quickly revealed the limited material selection, which was immediately incorporated into the design of these sketches. In particular, the profile was conceptualized as a single piece of material; however, the largest piece of wood sold by the PRL was 12" x 24"; therefore, the profile was broken into two sections. Similarly, the largest stock colored acrylic sheet in the PRL was 12" x 12", so this became the width of the cabinet. |
CAD.
The components of the CAD model can be divided into three categories.
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The Base:
The foundation of this cabinet is made up of 5 birchwood panels and 3 acrylic sheets. It can be seen that 2 of the birchwood panels come together to form a single profile of the cabinet. In combination with the back birchwood panel we are able to construct an outer wooden frame.
This frame is further reinforced with 3 acrylic sheets. The sheet within the cabinet has been fitted to hold the breadboard and also contains holes to allow for wires to travel from the front of the machine to the back. The sheet spanning the top of the cabinet serves not only as a means of reinforcement, but also as a mount for the reflectance sensor/retina scanner.
The foundation of this cabinet is made up of 5 birchwood panels and 3 acrylic sheets. It can be seen that 2 of the birchwood panels come together to form a single profile of the cabinet. In combination with the back birchwood panel we are able to construct an outer wooden frame.
This frame is further reinforced with 3 acrylic sheets. The sheet within the cabinet has been fitted to hold the breadboard and also contains holes to allow for wires to travel from the front of the machine to the back. The sheet spanning the top of the cabinet serves not only as a means of reinforcement, but also as a mount for the reflectance sensor/retina scanner.
Component Housing:
The remaining acrylic sheets serve as a means of mounting our various components. In general the removable nature of these sheets allows for easy access to critical electrical components within the project.
The remaining acrylic sheets serve as a means of mounting our various components. In general the removable nature of these sheets allows for easy access to critical electrical components within the project.
- The front red panel houses the potentiometer (steering wheel)/ button/ LED indicators/ servo for the gas meter. It was designed as a 12"x12" sheet to sit within a notched groove of the birchwood frame. This dimension was selected so that the stock material could be used while all laser cuts remained internal.
- The inner black sheets slide in and out of notches cut into the birchwood. They are responsible for limiting the degrees of freedom of the LED matrix by housing it within a backed frame (velcro was used in addition).
- The top red acrylic sheet simply covers the internal electronics, and required a single cut to allow clearance for the distance indicator hemisphere on the back wooden panel.
Peripherals:
The remaining pieces in the assembly primarily consist of all fasteners and electrical components; however, one subassembly of note is that of the steering wheel. In order to secure the steering wheel to the potentiometer a set screw hub was secured to the OOTB wheel via 6-32 machine screws. This in turn fastened to the potentiometer via a set screw.
The remaining pieces in the assembly primarily consist of all fasteners and electrical components; however, one subassembly of note is that of the steering wheel. In order to secure the steering wheel to the potentiometer a set screw hub was secured to the OOTB wheel via 6-32 machine screws. This in turn fastened to the potentiometer via a set screw.
Finally, it can be seen this base and assembly all fit within the specified project dimensions of 50cm x 50 cm x 100 cm (as drawing units are in cm)
FILES.
SOLIDWORKS files are provided below for reference.
THE FINISH.
FABRICATION.
The fabrication process primarily involved the laser cutting of materials (birchwood/acrylic) and adhering of the base assembly with glue. This process was relatively simple, as it had been planned both in our sketched design and CAD model.
One additional assembly was that of the purchased steering wheel to the potentiometer. This was accomplished using a hub purchased from the prl which was secured to the wheel via holes we tapped in the plastic and to the potentiometer via a set screw.
One additional assembly was that of the purchased steering wheel to the potentiometer. This was accomplished using a hub purchased from the prl which was secured to the wheel via holes we tapped in the plastic and to the potentiometer via a set screw.
Cosmetics.
Finally, decals were designed in Adobe Illustrator to add logos reminiscent of arcade machines, and to indicate the missile button, retina scanner, and gas meter. The decals were cut using the vinyl cutter in the PRL, and transferred onto the assembly. The dial of the gas meter was cut from vinyl, adhered to cardboard, and then cut out and glued to the servo.
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