PCB Design: DIY 2 Layer Boards

Project Info
Author: Chris
Difficulty: Medium
Time Invested: 7 Hours

Take a look at the above
tutorials before continuing
to read this tutorial.
           For an electronics hobbyist, knowing how to do PCB design is a must. Building prototypes on breadboards or with wire-wrap just doesn't cut it, once you reach a certain point. Then, a PCB board needs to be made specifically for your project. The previous tutorial Homemade PCB (Etching) showed you a quick, simple, dirty and easy way to make your own PCB. This tutorial will expand further and show you how to make a 2 layer (top and bottom) pcb.
           In PCB Design for hobbyists, 1 layer PCB's are usually enough to do the trick. However, when you evolve and start building more complex circuits you will need a second layer (or even more!) so that all the electronics in your project can be connected together.

PCB Design: 2 Layer PCB - Finished

PCB Design: 2 Layer PCB - After Etching

Purpose & Overview of this project
           This tutorial proposes to successully design (using Eagle Layout Editor), etch and build a 2 layer PCB board. The example design will be a simple 'led' flasher circuit that I'll give to someone special for their birthday! The circuit will have two 555 timers clocking in data to some 74ls164 (serial in - parallel out) registers. With a variable resistor trimpot to speed up or slow down the LED transitions.
           Understanding how the design itsself will work is not as important as is understanding the process for building the design in Eagle Layout (or the layout program of your choice) and going through the toner transfer and etching process. So pay more attention to the step-by-step process and not so much attention to the details of the circuit design.