Final Project¶
Old Project Idea¶
My original final project proposal was to create a light-up diagram of a body, using capacitive sensors or transistors as an input and an LCD/neopixels as an output. This project aims to benefit those who want to explore physiology but find conventional diagrams unengaging (me included!); by creating a more fun and interactive tool for the classroom, students of all ages can explore basic anatomy and learn about systems in the body!
I was inspired by Elaine Liu’s final project, Nadieh Bremer’s final project and one of my previous engineering projects from two years ago. At this point, a lot of aspects in my project are still tentative, but I have a general outline of what I want to achieve:
New Project Idea and Model¶
After considering the aesthetic aspect of my original project, as well as the lack of progress I’ve been making, I decided to restart on my brainstorming and choose different final project (week 7). My new approach was to choose something a bit more relevant to myself as a student. Thus, for my second project idea, I decided to create a portable smart desk with a built in pomodoro timer. This desk will contain three layers total–two wood layers serving as a frame, with a center layer made out of wood flexures and acrylic. I plan on having a neopixel shine through the acrylic.
| Method | How it will apply in my project |
|---|---|
| Week 2: Computer-aided design | I will design my project in my CAD program of choice; in terms of a project-specific component, I will design components for cable management and electronics housing |
| Week 3: Computer controlled cutting | I will design stickers to put on the side of the frame, and I will begin cutting the acrylic frame for the layering |
| Week 4: Electronics production | I will create the PCB I need to use for my LCD screen, neopixels, etc. (2 boards) |
| Week 5: 3D scanning and printing | I will print out the previously designed components in week 2 |
| Week 6: Electronics design | I will design the boards needed for the program and create a plan for how to wire the neopixels and the LCD screen |
| Week 7: Computer controlled machining | I will use the CNC shopbot to create the the flexures, main table frame, and the legs |
| Week 8: Embedded programming | I will investigate how to use different microcontrollers like the attiny with the RP2040 master board; additionally, I will explore the Adafruit library (for the neopixels) |
| Week 9: Molding and Casting | I will create a mold for the outside of the LCD screen and do a resin pour for the top layer of wood |
| Week 10: Input devices | I will program the touch sensors involved with the built-in timer |
| Week 11: Output devices | This week, I will program the outputs of my diagram, including the neopixels and the LCD screen. |
| Week 13: Networking and communications | I will use either UART or an I2C connection to communicate between different boards (one for neopixel, and one for screen) |
| Week 15: Interface and Application Programing | I will design the interface of the LCD screen |
System Diagram and Gantt Chart¶
I created this system diagram to visualize the application of each process in the final product. The TFT LCD model was taken from GrabCad.
My original idea was to have three layers, with a channel in-between for the acrylic to slide into. This was ultimately a failed idea and mainly existed as a driver for my project. I ended up remodeling so that the wood would layer, and the neopixels would shine up, as opposed to outwards. I CADded this design in Fusion360.
I also designed this gantt chart during midterms to determine what tasks I needed to complete leading up to June:
I also created a list of tasks to be completed at this point:
☐ determine the full extent of features with the lcd
☐ test the touch capabilities on the lcd (preferably inputs week)
☐ choose microcontroller for lcd - between the atmega328 or the esp32 (works with wifi)
☐ choose a form of serial connection between the boards
☐ design the lcd PCB and test
☐ design the rp2040 PCB for the neopixels surrounding the interior
☐ sand down the desk and make sure that the key fits (too thick as of now)
☐ deep engrave fab academy logo on the top
☐ paint the contact points of the wood with epoxy
☐ do the resin pour on the top layer and polish
☐ optionally design an outside protection piece for the screen
☐ design and 3d print top for timer case
☐ cnc (?) the bottom part of the case (hole + big pocket cut)
☐ callibrate everything
☐ assemble everything (add hinges too)
Bill of Materials¶
CNC: Desk Frame¶
Designing the Desk in Fusion360¶
I began designing my sketch in Fusion 360, creating a list of parameters. My design was originally a lot bigger, but given the design constraints, I had to scale it down by at least 60%.
Layer Description:
-
Bottom layer: serving as a base for the table, contains a hole for the cable
-
2nd layer: offset outline based on the bottom layer with two compartments outlined for electronics housing
-
3rd layer: offset outline based on the bottom layer, distance slightly smaller to create a lip for the neopixels
-
Top layer: offset outline based on bottom layer, center piece with a pocket for cup holder, hole for timer wiring, and a pocket/profile for the LCD screen; the channel will be filled with resin
-
Legs: legs will be fastened onto the bottom of the table with hinges
-
Rectangular key: will slot into the sides of each layer to keep the table together
Here are the parameters of the scaled down version:
I extruded by the material thickness, around .45” and created a pocket for the LCD screen and the cup holder by .125”.
CAM and Milling¶
After adding the dogbones extension I found in week 7, I exported as a .dxf and pulled the design into Aspire. I configured the job setup according to the bed size (96” x 48”) and thickness of material. I selected the machine bed as the z zero position.
In the main workspace, I created three toolpaths, including a profile, a pocket (.125” deep), and a cut-through pocket (.45” deep).
As mentioned in my week 7 documentation, the top piece was slightly messed up, so I created a new toolpath and remilled it. Here is what it looks like all milled out:
For more documentation, refer to Computer Controlled Machining week.
I post processed my boards afterwards with the orbital sander (180-330 grit sandpaper).
INSERT PIC HERE