Thanks again - this was a bit of a surprise!
That's one of the coolest parts of HN! This post was posted five days ago and went totally unnoticed by the community, probably, even OP has forgotten about it. Thankfully, HN had what is called Second Chance (https://news.ycombinator.com/item?id=26998308) and since this post is a masterclass in building a physical product, the mods decided to bring it back by featuring it on the front page, where it finally got the attention it deserved. A true masterpiece indeed!