I hereby certify that I am not simply asking someone else to design a footprint for me.
This is an auto-generated message that is in place on the “footprints” section of the KiCad.info forum. If I remove it and ask for a footprint to be designed anyway, I understand that I will be subject to forum members telling me to go design my own footprint or referring me to a 3rd party footprint site.
Are fiducials used for PCB building, or just automated component stuffing? In any event, where should they be placed? In all four corners, only 2 or 3 corners, single-sided or both? Should they be placed far away from each other, or close together? I can see a use for them in a manufacturing setting but are they necessary for the hobbyist who hand. is just going to stuff the board by hand? Should I use the 1mm round dot, or is there a better one for our purposes?
They are used for alignment by pick-and-place machines.
I never use them, by assembly houses adds them if they want to. If you want to add them yourself, ask your assembly house what style and position they want.
There’s global vs local. Global fiducials are usually placed very widely apart nearer the board outline and use at least (3) as 3 points define a plane geometrically. Local fiducials are usually placed very close to very fine pitched devices (~0.4mm and below). Sometimes assemblers can use footprint features to act as a local fiducial (like corner pads on a BGA) but it depends on the capabilities of the machine vision equipment used.
I usually always use global fiducials, but rarely use local fiducials as I generally don’t use many <0.4mm pitch devices.
Thank you for your answer. Three points determine a plane. Never thought about it that way. I thought 3 points prevented wrong way around, or wrong side. But I suppose level is more important. Anyway, thanks again.