Final project

Final Project

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. This idea is one that I came up with on my own, with some inspiration from a Mark Rober video where he looked at drones that dropped seeds to plant trees in remote locations which can be found here, but the idea for what mine will do was completely my idea. 


After talking to Neil, he pointed out how I was incorporating too much into my final project and that I should simplify it. I then decided to just do the seed dropping mechanism and the mechanism to fill in the holes. I still wanted my project to work, so I asked Merritt if he would be willing to collaboarte and place my mechanisms onto his wagon, and he said that he was fine with it. I then designed a new project Idea, and called it the seeed box, a planned on using the Xiao seeed within part of it, and it was a very pivotal part of my fab experience.

Once I had created the sketch I moved onto the CAD design. I created 3 slots for 3 different types of seeds, which would alternate between the 3 different types. The control for each of these designs would be controlled by the usage of 3 servos which would be connected to a RP2040 Pico, and then would funnel down towards the center of the wagon and drop the seeds in a whole. I also plan on using a VL53L1X TOF sensor to detect the holes and an accelerometer to properly time the dispensing of the seeds. Whenever the wagon would drive over a hole, it would wait a little based on the speed, then dispense the seeds and turn a servo at the end of a rod to fill the hole back in. Here is the design of the funnels as well as the box itself.

The plan I had for the rod mechaism would likely be similar to Prusa's wire hiding they would do, where they take the wire, place it in a T-bar, and place a cap over it. I would mount this on the back of the wagon and create a hole from where the electronics would be stored to make the cable mangement much easier. The time of flight sensor would likely be closer to the front of the wagon, but not too far just so that I could properly calculate when to drop the seeds and have time to deploy the servos.

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.


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


Files Used

To complete this project, I will use .py files (micropython) for the code, obj files for the 3D printed parts (which a model of my project can be found here), aspire files for the mills, and eagle files for the board mills. 

Design of the final project

Deadlines

For my project deadlines, which can be found on my fab site were unfortunately not able to be met. This happened because I had to try to finish each other week before moving onto my final project portion, which leaves me with just some of the project done. 

Steps