I’m working on an Arduino-based project and designing a custom 2-layer PCB to integrate multiple sensors and modules. I want to make sure the design is efficient, especially when it comes to power distribution and grounding. Should I use a dedicated ground plane, or is a mixed approach good enough? Also, what are some best practices for trace routing to avoid noise and interference issues?
If anyone has experience with similar projects or any useful tips, I’d love to hear your insights. Thanks.
It’s a mix of digital and analog signals, but nothing high-frequency—mostly sensors and communication modules running at low speeds. The board has both 3.3V and 5V components, and it’s for indoor use, so no harsh environmental factors to worry about.
Without specifics it hard to give any advice. "Low" and "high" don't really mean anything. There is always some noise on analog signals, the question is how much is acceptable.
One ground plane should be sufficient. What I've learned is that you can have two groundplanes, one for digital one for analog, and then join them at one point. How this is done in practice is not my cup of tea.
The 3.3 and 5 V traces you calculate from the current needed.
One common approach is to fill in one side of the PCB with GND as @Larryd said. It has two advantages. 1- You can connect grounds to the nearest available GND , as opposed to routing a track for them. 2-Grounding the copper-filled surface can absorb a good amount of noise. But if your digital chips are very sensitive to noise, you need to encase the portion in a metal closure like the stuff you see inside cell-phones, etc. or encase the high noise part in a metal box like what was common in high-voltage box in old TVs.
I built a PCB to interface three main subsystems to a GIGA.
38 Optical Sensors Low Level Analog
38 bit tristate shift register
Switching power supply w/ digital controls for voltage and current
I used a 2 layer board and reserved separate areas of the board for each and kept the supply and ground lines strictly separate. I gave the Analog portion its own ground plane on one side of the board in blue, and a separate ground plane pour around the switching power supply components in red and a full ground plane in blue on the bottom side. I didn't interconnect grounds from these different areas on my board but connected them to the relevant ground pins on the GIGA. I used the 5V supply just for the switching power supply and used 3.3v for the analog and low current digital sections. I used .1uf decoupling capacitors at all sensitive circuits.
The ground planes did make a big difference from earlier versions that didn't have them.
I use JLCPCB to fabricate the PCBs and their EasyEDA Pro tool to design it. It has a very nice and easy Copper Pour tool to automatically create a ground plane around components and other traces. I'd highly recommend JLCPCB for high quality at a very very low price. Turnaround is under a week to your door.
Jim, I'm curious what kinds of issues you've had with them?
I've had JLCPCB make about a dozen different iterations of the board I showed above plus several other smaller but high density SMD LED carriers including cutouts and channels without a single problem. If you zoom in on the image of my board above particularly in the area of the double row of 14 pin TSSOP packages you can see some pretty high density areas with fine detail.
As I say there haven't been any issues of any sort. And the boards always show up in less than a week and for a total cost for 5 boards of only $7 plus shipping.
So for my purposes and likely for most Arduino class users and designers I'd say that qualifies as high quality. Are there likely even higher quality fabs, sure. But I don't see anything I need done better than what JLCPCB already provides. And their EasyEDA Pro is feature rich and super easy to use. (Gerber files accepted too) So what's not to like.
I haven't used any other PCB fabs in the last 30 years. Before that I was involved with using commercial fabs back early in my career. Before choosing JCLPCB I conducted an online review of about half a dozen fab houses and their EDA tool options. I liked EasyEDA pro and its direct integration with JLCPCB for one click ordering of my design. I experienced very fast delivery (under a week) for a low cost (intro price is $2 for 5 boards, small boards are regularly priced at $4 total for 5, and my medium size board with some fine details are $7 total for 5)
JLCPCB does everything I need for my Arduino projects and they do it fast, reliably and inexpensively. What's not to recommend highly? I never said they were the best in any particular way. I showed the kind of PCB they were able to fab for me so others can judge if they need something more or less complex. And I gave specifics about costs and delivery time.
So far you haven't provided a single data point about where they fit on your perceived scale of FAB capabilities. And if you don't like my recommendation then please do let us know what aspects you find JLCPCB lacking and what fabs you find better or more cost effective.
Absolute quality is not, as far as I see, the overriding consideration for hobby users. Provided that the total price and delivery times are reasonable then I am happy with the agreed level of quality.
Also, I would never build up sufficient experience with one PCB supplier to be able to condemn their quality outright. If, after one or two attempts with them, the result is a poor experience, I'd simply move on. The market place is very competitive.
I do use JLCPCB and will continue to do so unless something goes badly wrong or a competitor emerges with a better offer.
I have had probably hundreds of PCBs made through JLCPCB, I can only recall ever having one issue, which was one broken track. Otherwise, registration can be a little off, and silkscreen not very precise. If you don't push the limits these are not really a problem. I have noticed they have got better though.
My usage is hobby, if I needed commercial quality board I might look elsewhere - and pay accordingly. But for their price it's hard to beat.
