Week 16 - Applications and implications
How it will work
For my final project I want to create a conjoined design with Merritt. My design will be a box tht fits atop his wagon that dispenses seeds when a hole is detected underneath the wagon. There will be 3 different compartments for the seeds, and they will each feed into a singular tube in the center of the lab. Then there will be servos in each of the compartments that will dispense the seeds. At the bottom of the wagon there will be another servo that will fill the hole back in. The way I will gauge when to drop the seeds will be with a time of flight sensor and an accelerometer. I will have the time of flight sensor connect to an RP2040 PICO, along with all the servos. The accelerometer will be attached to a separate XIAO RP2040 seeed, and it will communicate to the RP2040 PICO via UART communication. These two systems will work in tandem to controll when the seed gets dropped.
What processes will be used?
For the actual box, I will CNC that in order to carve out some channels for easy access to electronics as well as to make everything sturdy by using larger wood and inserting holes at the appropriate spot. I will likely laser cut part of the divider, the upper part, and then I would 3D print the bottom part, as well as the tubing. The boards I use for the electronics will all be milled myself. Part of the dropping mechanism will be molded in order to fulfil molding and casting week. I can also write a program that will interact with the dropper by telling and displaying to my computer what type of seed is being dropped.
Work completed
So far, I have completed the majority of the 3d model, and have a board to test my communications with the accelerometer. What I still need to complete are the actual prints of my parts, my mold and cast, and all actual boards and electronics need to be made and connected. I also need to mill and laser cut the housing for everything.
Bill of materials
- Half inch plywood
- 1/8 inch Acrylic
- 1 VL53L1X TOF sensor - $19.68
- 4 HS-311 servo motor - $13.49 each
- 1 MPU6050 accelerometer - $0.99
- PVC pipe
- 1 sided copper board
- 1 RP2040 PICO
- 1 RP2040 XIAO seeed studio
## Work schedule
Day 1 - Monday June 5: Finish cad design (1-2 hours), begin milling and printing pieces (undetermined)
Day 2 - Tuesday June 6: Continue printing, breadboard electronics/design board(4-6 hours)
Day 3 - Wednesday June 7: Design aspire files and corel files for milling and laser cutting(1-2 hours). Mill box and assemble(3-5 hours). Laser cut acrylic piece(<= 30 minutes). Mill boards (if time and not done already)
Day 4 - Thursday June 8: Mill boards (if not done already, about 1 hour), solder boards(about 1 hour), test and troubleshoot boards (rest of day)
Day 5 - Friday June 9: Assemble full project and test, try to get working and interface with merrritt's project
Days 6 & 7 - Saturday June 10 & Sunday June 11: Complete documentation and begin/finish video editting and slide
Day 8 & 9 - Monday June 12 & Tuesday June 13: Catch up on missed work from the past week
Questions to be answered
The one thing I am still uncertain about for the final project, is how to fully power all 4 servos, because I know they can't all run off the on board power supply of the RP2040 pico. I am not sure if I need a voltage regulator or not, or even what voltage regulator to use if I do need one.
Determining success
The success of my project will be determined by how accurately the seeds are dropped, and if the seeds are alternated correctly. IF my project can detect the whole and somewhat accurately drop the seeds in the hole, and cover up the seeds somewhat, then that would definitely be seen as a success.