Output Devices

This weeks task was to measure something: add a sensor to a microcontroller board that you have designed and read it.

Requirements

Battery Support

Needs to be able to operate off of a single 18650 battery cell, this cell will be 3200mah, and was purchased from a U.S. retailer here.

Wifi Support

This is pretty simple for me, and is part of the the microcontroller im using. As with the other boards i've made, I plan on using a esp32 series chip, almost certainly the esp32-c3-wroom-02. Im very comfortable with using this chip, so it was the obvious choice

Stepper Driving Capabilities

It needs to be able to drive a stepper, after doing research the primary plan for this was a custom driver board, based off the (DRV8835). I choose it primarily because I saw this board from Pololu, which used it, and just looking at the board it needed like 4 components to work. Doing research, it was perfect for my project as it

USB-C

while usb micro is easier to work with, thanks to its pinout being 5 pins, vs the USBC's 16, and the USBC requiring at least 2 resistors to work, and specific capacitors on the data lines if It was a professional project. I don't care however, as the USBC will hopefully only be needed to be used once before switching to to an OTA update configuration so I am going with the bare minimum for this

Schematic

After selecting components based on my needs, I started with the schematic. As I intended this to be a "frankenstein" board, I started by designing a footprint for the pads I would use pads to intersect here. Here is where I messed up and fixed it later, as I originally intended to connect the pads so that they were really long. I realized that this would be very hard, as solder likes to pool in the middle. To make it easier, I made the pads connect so that they would form a square, which would

Component redesigns

In order to more easily use some of the components, I went and redesigned the schematics of them. This includes the tp4057 IC, which I redesigned to look identical to the example I found, and the USB-C module I use, which I moved the pins around so that it was much cleaner to work with

PCB Design

after finishing the schematic, I started on the design. Because of all of the designs (except for the USB-C) being intended for milling/at home fabrication, I had to be smart with how I routed. I ended up having to use 2 zero ohm jumpers in the board, in order to make the design possible. This isn't the best possible outcome, but its what I got and if I redesigned it to use traditional jumpers (which I should), then it could probably be made with none of them.

Initial Setup

Pads

USB-C module

Battery

Battery Monitor

Pads

Stepper Driver

Microcontroller

Checking Design

Stages

Hero Shot

printing to check, getting correct connector

after designing it all, realizing that since im using copper etching I could of edited the pads on the chips itself to not have them block certain paths, so I did

grok cooking https://grok.com/share/bGVnYWN5_facea7c7-fa79-4927-b924-0f15f24c274b