0000 0000 0001 0111

Your own PCB

So far most of the circuits on this blog have been whipped up on a breadboard or a generic PCB. The solar joule thief showed a PCB which looked a bit more professional, but how does that process actually happen? 

Well, I think I've made most of the mistakes possible and some of my earlier efforts with PCBWAY and JLCPCB were quite comical. It might be worth listing the steps and the gotchas that can crop up along the path to your own PCB.

1. Design your circuit on paper. Use a calculator to check some of the voltages and current in the wires. Later when you look at track widths and separation this might come in handy.

2. Test your circuit using appropriate simulator software if you're up for it - it does take an investment in time. I think it's worthwhile before you fry stuff to have a look at the circuit in a simulator. This is particularly useful if you are experimenting with standard components such as the 555 timer (e.g. as I did here using TinkerCad circuits) or perhaps for checking the flow of logic before wiring the myriad of connections (e.g. as I did here using logic.ly).

3. Breadboard the circuit paying close attention to the voltage and current requirements of your components. In this regard you should at least glance at the datasheets of the components you have chosen! For instance if you are using an LM317 voltage regulator (as I did here), then download and look at the limits shown on the datasheet. Don't ignore decoupling capacitors - these little beauties (generally I use a combination of 47uF and 100nF) smooth out the supply and can make a huge difference to the stability of your circuit. Look carefully at the pinouts - correct orientation of the pins can save you a few fried components. As an example, you may have been making a few projects over the years using the Attiny13 as shown here:

Flushed with success you might then migrate the project to the newer Attiny202 with very different pinouts as follows:

For some reason VCC and GND have moved - which if you're not careful could result in some fried chips!

4. Open up EasyEDA and place your components as required. This blog isn't about how to use this software, and in fact I've used KiCad and Eagle to do the same thing - so choose your weapon! The main consideration is that your software produces what is known as a Gerber file (usually a zip of many files) which describes the PCB in a standard format.

EasyEDA and connecting up your components

EasyEDA placing components on the board

Clicking Gerber, check DRC and head over to manufacturing at JLCPCB

It took me quite a few times to understand what a "ground plane" is and how it can be useful. My advice is to definitely use this feature of PCB design. I learned from watching MickMake and reading a lot of online tutorials. Here is a very quick video showing the addition of a ground plane to a PCB - this was something that I struggled with for a long time.

5. When you are in the JLCPCB site, one definite selection should be to panelise (if you're searching online try "panelize") your board. Before I knew about this feature on JLCPCB, I might spend $18 on 10 boards (which sounds great), instead of panelising and spending $18 on 120 boards - big difference! I learned about panelising from this youtube video which also explains the whole process - what a revelation. If you want a more in-depth explanation, Great Scott has an awesome video here.

To illustrate the whole process I will make a PCB over the next few weeks on this blog. I think I'll use a 555 signal generator as the premise for a few reasons.

Firstly, who doesn't love the 555? It's a good starting point, pretty robust and the central character in a lot of useful circuits. Secondly, from time to time you need a quick reliable clock - for example when making a flashing display - as so many chips rely on a clock signal. Thirdly, there are a lot of example 555 timer circuits out there on the interwebs, so not much time will need to be devoted to actual design and then we can concentrate on the production of the PCB.