Cute Little Valentine's Day Gift

PCBway: only $5 for 10 pcbs from https://www.pcbway.com/?from=CZcouple

It’s almost Valentine’s Day. This year, instead of giving her a rose bouquet, I wanted to express my love by gifting her an electronic breathing heart. This is yet another "cheap DIY kit" intended for educational purpose. There are a few variations of the breathing LED projects with similar setup, however the one with blue LEDs attracted me a lot.