My First Printed Circuit Board

3 min readMay 29, 2020

This year I had the pleasure to begin learning the fine art of printed circuit board design. Despite the hardships that the Coronavirus has caused, social isolation does have its benefits. In my case that’s translated into focused learning time.

As part of my IoT work I set out to build a connected SPo2 and HeartRate monitor which is capable of securely transmitting biometric sensor data to a cloud-hosted microservice. I demo’ed the device during my Redis Conference presentation this year on the use of IoT and Connected Fitness with RedisGraph.

To keep things relatively simple and inexpensive, I started learning a tool called EasyEDA via Amit Rana’s PCB design course on Udemy. Amit did an amazing job of making the subject accessible. I completed the three hour course in just a few days.

Using EasyEDA, I was able to order actual boards via JLCPCB right from within the software. My first three board designs suffered from my own minor design errors. But I learned more than if my first attempt would have been successful. Live and learn!

By revision 3 I had a functioning board layout.

I chose to use the Adafruit HUZZAH32 — ESP32 Feather, largely because of my familiarity with Adafruit components and because I wanted to use BLE to configure the microcontroller for WiFi use. I did the programming using Visual Studio Code and PlatformIO and along the way I took a bit of deep dive into hardware debugging and wrote Advanced Microcontroller Debugging using the ESP-PROG here on Medium.

I used a small OLED display to include both text and graphics and a SparkFun Pulse Oximeter and Heart Rate Sensor to sample biometric data. The device sends data to a cloud hosted, containerized microservice using WebSockets over SSL.

My first attempt at using the Sparkfun sensor was unsuccessful, perhaps due to faulty soldering. In a later attempt I used an inexpensive digital microscope to inspect solder connections.