SparkFun Forums

[unsped]

so im playing around with the sparkfun library for the buttonpads, and the pads don't seem to be on any sensible grid pattern ... making proper routing seem impossible. even from pad to pad it seems to be a very fine almost prime number lol.

my best guess is that the board is metric, and the button pads are some arbitrary distance away from each other.

am i just an idiot or is this part bonkers?

which brings me to my next question, what is 'standard' grid spacing for parts, through-hole and smd. i've been keeping with 50/25mil in eagle as my gridsize ... what is generally used?

as an unrelated note is there a way to recalibrate the grid in eagle with a selected point?

[Philba]

some parts have their pins on pretty random grids. For example DB9 rs232 connectors are wired. There really isn't such a thing as standard grid for pins. Some are laid out on a 100 mil grid, some on 50 mil, there seem to be several typical grids for metric but there are a LOT that don't have any obvious logic to their pin spacing. Wait until you get to surface mount parts...

One trick that helps with eagle is to manually route traces coming from off-grid pins (i.e. start from the off grid pin). This usually does the trick. If you are autorouting, just rip-up the first segment or 2 of the trace coming from the offending pin and re-route them.

I typically use 50/12.5 mil as my grid.

Edit: I looked at the button pad - it appears to be on a 1.6 mm grid. The trick I described above works with it.

[unsped]

so im guessing its fairly normal then to have accute angles from offgrid pads. ideally only as long as it needs to get on grid. if you can keep the acute angle route within the via or pad ... it ends up never really showing up on the board .

[bigglez]

so im guessing its fairly normal then to have accute angles from offgrid pads. ideally only as long as it needs to get on grid. if you can keep the acute angle route within the via or pad ... it ends up never really showing up on the board .

Yes.
Run the DRC with the "check angle" on (See the DRC's Misc tab).

[Philba]

In almost all cases, you can avoid acute angles with the technique I posted. On that button pad, I was able to route traces that came straight out. If you are using the autorouter, I recommend you learn how to route manually. It's not nearly as hard as it seems at first and you will get a better board for it.

There is a DRC control to get rid of the error message on acute angles.