15. System Intergration¶

Files¶

Overview¶

This week I planned out how I would package the electornics of my final project and began testing my code and electronics on a breadboard.

Dog Body Design¶

I used Fusion 360 to design my body since I wanted to laser cut test the body and the parameter button would allow me to use the same design for different material. The first model is very simple, it has 5 holes: two on each long side for the legs and then one in the back for the tail. Besides that everything else is part of my press fit design. I made it about the size of a portable charger since thats how Im currently trying to power my electronics and then about double the width of a portable charger to try and account for the pcb. Heres the fusion design:

And heres the first test cut in cardboard:

After seeing how poorly that came out I decided to switch over to a 3D printed. I used calipers to measure the board and its componets to make a 3 part body. The middle would be where all the electronics would be located. I have places for the servo wires to run where they will end up at a open up part of the body for the servo to move. The top part is the cover for the electronics, it covers up all the running wires and PCB, while also having a jetted out slot for the step responce touch point. The bottom part of the body is the holder for the portable charger thats powering the servos and board. Heres the current design I have:

And heres the pieces printed out:

Board Design¶

This week I also worked on designing my board for the final project. I took what I learned from Output and Machine Week to make the board. It has 4 pinheaders that are 3x1 for the legs and another 3x1 for the tail servo. I also have two pinheaders that are 2x1. One is for the external power supply and the other is for the rx and tx pinouts for the step responce. Finally I have the ESP32C3 as my microcontroller as it gives easy access to a web server and I have been using them for all the weeks up to now.

Heres the schematic view:

Heres the PCB Design

PCB¶

For my final project I knew that the board needed to be double sided, the issue was that the fab lab had gone through all the double sided pcbs during machine week. My solution was simple, I took a single sided pcb and milled both sides of the board as two different pieces. This meant they were the same size and had the holes in the same place. Once they were both milled this is what they looked like side by side:

After looking at them and test lining them up I was able to see through both holes to the other side. Once that was acomplished, I used hot glue to press the boards together. Afterwards, I soldered a wire through the holes so that the boards were connected. Finally I soldered on the pinheaders for all my external electronics. This is what both sides looked like:

Now that the board was finished I was able to plug in all my servos into the board and the once very messy breadboard filled with wires became this:

Heres a wide view of the servos connected to the board:

I made a new design with large holes in vacant areas of the board for screws so the board is locked into the body of the dog. Heres what the new design looks like:

Reflection¶

This week was very helpful for getting my foot in the door on my final project. I was able to design two crucial componets of my dog and they look pretty good. It wasnt a very difficult week since now im using all the skills I learned during the course of Fab Academy to design my board and body.