Week 5: PCB Design

Designing a Circuit

Objective

The goal for this week is to use EDA software to design a schematic and plastic cirtcuit board (PCB), which I’ll then physically manufacture next week.

Group Project

This week’s group project focused more on how we’ll eventually troubleshoot our PCBs. We examined how to use a voltmeter to measure voltage in different areas in our PCBs to ensure that we aren’t missing any resistors.

Schematic Design

For my final project the main integrated programming will be in a custom mini-keyboard resembling a blackberry. Originally for this week I planned to build a PCB for the keyboard with some integrated bluetooth. However, for my first forray into electronic design and manufacturing, I wanted to keep things simple, so I also designed a basic LED circuit with the ability to test out bluetooth functionality. To learn more about the keyboard, see the ‘Final Project’ page.

For my “simple” design, I essentially divided the priorities into two parts

  • First, I had a basic circuit in series consisting of a tactile switch, a resistor, and an LED connected to a GPIO and ground. This is to test my basic ability to solder and generally construct a circuit.
  • Second, I connected three more switches to three other GPIOs pins (and ground, of course). These switches won’t have any visual effects on this board, but will be configured to light up an RGB LED on another board via bluetooth.

Basic Schematic

For the second part, this obviously requires a receiver board:

Basic receiver board

As I mentioned before, this board simply features an RGB LED connected to another XIAO ESP32-C3.

PCB Design

The PCB designs were not especially surprising, but were successful. I was surprised by how much the footprint ballooned when incorporating the pads for the switches. This actually changed my part choice for my final project, as I realized 6mmx6mm switches might be too large for a compact mobile keyboard.

Basic PCB

File Links:


Written By

Nathan Wiegand