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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.