I did a search on the forum here and haven’t been able to find an answer. I’m a novice at designing PCBs and want to design/build a simple breakout board for a ConnectOne Nano Socket WiFi to breadboard with an Arduino Mega. The Nano Socket WiFi board has a two 2mm pitch 15 pin headers which I’d like to place on my PCB and a typical breadboard/shield takes .1" pitch. So here is my question.
How do I make sure sure the spacing on the board is correct for both component and the breakout pins to the breadboard so that everything will line up?
I’ve done the metric to imperial conversion and it’s not a clean match. For example, the data sheet for the Nano shows the distance between the two 2mm headers as 20.88mm (24.88 board width less 2mm each side). The conversion of .82204" doesn’t fall on a .1" boundary for my .1" pitch headers.
BTW, if anyone has a simple breakout board design for this component they’d be willing to part with, I’d be willing to take the easy way out.
It depends on the PCB software you are using, I don’t have any problems using Pulsonix for that sort of thing. Post the URL for the data sheet so that we can see what is involved.
With Eagle you can change your units whenever you like. I suggest you modify the menu.scr to give you a selection of grids. Unfortunately a 2mm pitch device will never fit on a 0.1 inch grid.
I have found the Info command very useful for manually adjusting the XY co-ordinates of devices or traces that didin’t quite go where you wanted.
Also, with Eagle alot of commands do special things when used in combination with the [Shift], [Ctrl] and [Alt] keys. For example: when moving off-grid components, by holding the [Ctrl] key, they will snap to the current grid.
Not only are there 2mm and 0.1" headers, SOIC’s are 0.05" and the smaller foot print chips are on metric pin spacing.
What I do in any of the CAD packages I use is create a part using the appropriate grid, either imperial or metric. Then just place the part on the PCB and route to the pads. The traces do not need to be spaced (snapped to grid) the same as the device pads, just close enough to connect.
I tried changing units of measure from inches to mm and that seemed to work. Here’s a few other tricks that I found while working:
As I needed to go exactly 20.88 mm from one header to the next on the ConnectOne part, I placed the first header (near the origin) and used the Info of the 2nd to place it exactly 20.88 mm’s away with the same X coordinate.
The routes don’t line up exactly. I put all of the traces on the bottom and that typically forced a via close to/on top of the header pads. Zooming in and clicking on the via usually gave me an option to change that very small trace segment to bottom. If not I moved it around a bit and exposed more of the trace.
I cleaned things up, labeled the layout, and printed to PDF the 1:1 but found the components slightly off. I’m using a header from Sparkfun and another 2mm header from another library. Is this typical?
I’m also interested in reviewing my layout in gerbv if I can figure out how to get it installed on my Mac. In the interim, I looked at the GB* files. Is there a good tutorial on reading these files?
