Lead free is recommended, even though it's really the lead dust that gets you. Also lead can't be washed out with soap?

Nice hackaday article comparing the different lead-free solder types. https://hackaday.com/2020/01/28/lead-free-solder-alloys-their-properties-and-best-types-for-daily-use/

• For my through-hole projects it's probably not an issue.

Comparison: https://pcbshopper.com/

China ones are basically 10X cheaper. I wonder why?

Also OSH park ones for medium run (which includes fancy HASL coating) is 3X price of JLCPCB. https://docs.oshpark.com/services/two-layer-medium-run/

Or DIY quickly for $4k startup costs. I think they'll figure out how to get it working better: https://www.voltera.io/

“Conformal Coating” is the key word. Plasti-dip sorta stuff

iFixit guide to different connectors.

Typical one is flat flexible cable.

• Good tutorial: http://www.piclist.com/images/www/hobby_elec/e_eagle44.htm

#To remove an eagle package/symbol from a library, just use the remove command (clunky, but works)
"remove qfn16.pac" or "remove 7-SEG.sym"

• Hot glue gunning the cables
• Press connector makes a ribbon cable, but always NX2 (not a single layer wide)
• pcb cable strain relief (zip tie, looping cord around inner posts, the bendy thingy)

• To add ground plane, draw a polygon around board on bottom layer. Then name polygon GND.
• Set Copper/Dimension to 20mil…don't remember why though!
• Having a power switch is always nice, just to switch between “on” and “off” or between two different power supplies.

• Great for debugging with a scope! A cheap through-hole way using component leads:

• A more expensive but more elegant surface mount way: from Keystone Electronics (they give you free samples)

• Dorkbot PDX has a good deal: $5 a square inch for 3 boards w/ free shipping. Great for prototyping and one-offs.
• Apparently iTead Studio does 10 for $12 of ~2“X2”max boards. Might be better for larger quantities.
• Oregon company that does PCB's and makes PCB123 as well: http://www.sunstone.com/

• Probably could have put small and easily solderable components (resistors, caps) on underside of board to save board space and solder them by hand afterwards. Battery is just going on top of it!
• Dang…this is a tiny board!
• Made the mistake of hooking up the JST LiPo battery connector backwards! Sparkfun's diagram was ambiguous and I didn't double check on the layout and the battery >.<

• Also, want to change input switch so that it doesn't depend on battery (but will always charge when plugged in).

• Flipped up LM317 >.< Switched Vout and Vadj!