I think it's going to be an LED tester / polarity finder

A project log for Effect of moon phase on tombstoning

I'll assemble a PCB with a couple of very small components every week and track the effect of moon phase on tombstoning.

ChristophChristoph 10/25/2021 at 21:260 Comments

Sorry that this took a year to figure out, but I've finally come up with a design that might not be totally useless, but easy to build and rather inexpensive: An LED tester and polarity finder.

When I had to handle 0201 LEDs, I quickly learned that they don't really come with useful polarity markings. Yes, there's something on the bottom, but when I try to flip them around again even with my best tweezers, chances are that they end up in any orientation. So I need to find polarity while the LED is already facing up.

It's also a bit hard to decide on a current limiting resistor before knowing how an LED will look when a given current is flowing.

So here's a polarity tester that allows to find the right orientation AND the right current limiting resistor:



The resistors are in 0201 packages to fulfill the actual purpose of this design: see if the moon phase has an effect on tombstoning. 4 land patterns are stock KiCad, 4 are a custom (hopefully better) land pattern.