First ever PCB Design

Dear Community

I’ve done a lot of R&D in the past week to come up with my first PCB Design for my Arduino Project. I am at a point where I need a set of fresh and experienced eyes that take a quick look at my design. As a trained aeronautical engineer I mainly work in the field of numerics and therefore never really had to bother with explicit circuit design.
Before I have my PCBs printed I’d really appreciate some input in hope of saving the cost of reiterating.

The projects goal is to build a small pc peripheral for flight simming (radio management panel).

My schematics and pcb-plots are attached. Are they fit for printing? Since my applications use is not that critical I did not do any attenuation, transline, spacing, trace width etc. calculations and went with rules of thumb.

Some Notes:
-Copper pour on both Layers to GND-Network
-Trace width for 5V, GND, ledDriver 1mm
-Trace width signals 0.25mm
-Clearance globally 0.25mm
-PCB Thickness 1.6mm

-FSMIJ62BA04 https://www.te.com/usa-en/product-2-2213818-9.html
-EC11EBB24C03 EC11 Series - Basic information

Any Input is much appreciated and I will be more than happy to return the favour to the community should the opportunity ever arise. Unfortunately there’s no numerics or aerodynamics subforum on here :wink:

Thank you!

rmp_revB_schematic.pdf (134 KB)

rmp_revB_pcb.pdf (54.4 KB)

Suggest you wire switches as S3 here:

Thank you Larry. I was debating internal pull ups. Reflecting on it again the pros outweigh the cons. Heat is not an issue. It safes a few cents but a lot of nerves. Because my soldering skills are abysmal :slight_smile:

I don't see any indication of Ground Plane on the top & bottom layer.
Figure out how to add those, and get rid of the ground trace running all over the place.
Otherwise, the copper just gets etched off the board and does you no good.

Suggest signal traces be .01” (10mil) minimum, if there’s room use 15mil.

For power use .025” (25 mil), if there’s room use 50mil.

Make your thru hole pads 60 mil if there’s room.

Make sure you have mounting holes.

I like a power LED on a mother board.

If the Mega and switches are on the same side of the mother board, it means the Mega will cover your switches. :o

larryd:
Suggest signal traces be .01” (10mil) minimum, if there’s room use 15mil.

For power use .025” (25 mil), if there’s room use 50mil.

Make your thru hole pads 60 mil if there’s room.

Make sure you have mounting holes.

I like a power LED on a mother board.

If the Mega and switches are on the same side of the mother board, it means the Mega will cover your switches. :o

What is wrong with the trace widths he has quoted? Unless there is some RF matching or loss problem the bigger the better. He has plenty of realestate on the board so there is no problem.

With regards to your abysmal soldering remember flux is a technicians best friend. I find liquid flux brushed on from an old nail polish bottle or flux gel from a syringe the best. Although a lot of people here say there is enough flux in modern solder I disagree and have proven it time and time again when teaching soldering in the military. I would challenge anyone to a soldering contest to prove my point but alas we are all too far apart.

PS. Look up some soldering tutorials from professionals, they will help.

PPS. Let the wars begin.

Have found out over ‘many many’ years of PCB designing, traces reduce in width during etching, the suggested larger dimensions are a good trade off.

Larger thru hole pads are always best for self proclaimed poor solderers.

The OP can obviously do what they want. :wink:

Well he has suggested 1mm for power which is ~40mil. You suggested 25mil so his is bigger. Maybe you confused mil with mm. Just saying (I hate that).

Hi,
When posting with attachments can you please make them jpg, as they are easier to load on some platforms.
Export as jpg.

On your PCB don't forget to silkscreen a date, version, name so as to identify its genealogy as you make changes.
Don't scrimp on track width.

[soapbox]
You have purchased a blank PCB, loaded with copper.
You are paying someone to remove that copper, which you purchased.
They are not giving you a discount for the copper they reclaim.
You have plenty of room so keep YOUR copper and use it to help provide strong solder points and good current carrying capacity.
[/soapbox]

Thanks.. Tom.. :slight_smile:

Are we having a bad day, you seem bristly.

Yes 25 mil was suggested, however, 50 mil was recommended if there was room.

I have run out of meds.

I have some, what colour would you like ?

I'm all stocked up, I did a drug run to the pharmacist yesterday. :o :o :o :o :o

Blue ones are good.

For power use .025" (25 mil), if there's room use 50mil.

I'm a big fan of thick traces, but 50mils ought to be overkill for anything Arduino-related. (is OK for up to about 3A with 1oz copper on outer layers and 10C temperature rise, according to online trace-width calculators.

I usually use 1mm (~40mil) for long power traces on PCBs, and they end up wider than almost any commercially produced board I've ever seen. (not that all of those are good examples.) I would have ground planes, though.
With "lousy soldering skills", you might want to make your pads a bit bigger ("RestRing" in EAGLE; I'm not sure about KICAD.)

It's not exactly how I'd do it, but I think it looks pretty good for a first PCB...

Thank you Larry, WestFW, windowze, tom and crossroads!

Summarizing your inputs:

  • Export and share on forum as JPGs
  • Export layers seperatly with labeled traces (@crossroads I exported the design before pouring the copper)
  • Signal traces 0.381 mm
  • PWR/GND traces 1.27 mm
  • Bigger through hole pads (rest ring)
  • Power LED on PCB
  • Silk screen Date, Version and maybe an Icon/Logo
  • Use Internal Pullup
  • Use flux while soldering

@Larry / On the subject of covering the switches: I was planning on soldering male pin header on the bottom of the pcb so that I only cover the arduino.

Thank you everyone! As soon I as I am done with a new revision I'll post the results. This is a great learning experience. One could simply go out and buy the hardware I am trying to build. But where's the fun in that!

TomGeorge:
[soapbox]
You have purchased a blank PCB, loaded with copper.
You are paying someone to remove that copper, which you purchased.
[/soapbox]

With plated through holes the normal manufacture technique is something like:

  1. take blank FR4 or whatever board, no copper.
  2. drill all the plated holes / vias
  3. electroless copper deposition
  4. electrolytic plating of more copper to full thickness
  5. photomask and etch the traces. Copper from the etch recycled to step 4
  6. tinning, soldermask, screen printing, drill all the non-plated holes.

Because of the recycling you theoretically pay only for the copper used, depending
on the fab house's pricing policy (they may simply aggregate the cost to everyone).

With multilayer boards things are more complex of course, as the stack has to be bonded
before all of these steps.

Do I understand you correctly ... there is no real need to do a copper filled zones in my case (2 Layers)?

Hi,
I think you will find the PCB cost has nothing to do with the pattern you want etched, just PCB size, number of layers, copper thickness and any mechanical requirements.

Tom.. :slight_smile:

The PCB material is procured as copper clad sheets over fiberglass.
It is generally not procured as bare base material with copper then added to it.
Leave the copper in place, it helps cut down RF emissions, it can help act as a capacitor with the power traces, and the copper can help with component cooling.

Leave as much on the board as you can.