It is surprising to see this question on HN. We regularly see Show HN projects that cost tens of thousands of dollars in time (assuming a typical software engineering hourly rate), but that aren't all that innovative compared to existing options. And we love those projects. Why would DIY effort outside the software domain be any different?

I don't think this is a valid comparison. In DIY projects, your time is free: you don't count your engineering hourly rate as part of the cost of building the thing. The only cost is the actual costs incurred, which is mainly parts and materials.

So a Show HN project that's purely software effectively is worth $0, because the creator made it in their free time, instead of spending that time playing video games or watching TV or whatever. And a Show HN project with a lot of software running on a RasPi effectively costs only what the RasPi cost the author.

Here, people are complaining about the actual hardware cost to the creator, not the creator's time spent, which you're also ignoring.

When I was 20 years old, I would have agreed with your position. But that was a long time ago.

Everyone, no matter how materially wealthy they are, gets 24 hours per day. That time is, by definition, 100% of the time that you'll get, which means that its value (intrinsic) is nearly infinite. This is true even if its price (extrinsic) is zero.

My point in mentioning an engineering rate was not to quibble about what free time costs. It was to say that even if someone confuses price with value, we can agree the the value gained from time well spent is very high. So it seems strange to criticize a hardware project that had $X of "hard" costs, $Y of "soft" costs, and $Z of benefits, when we regularly admire software projects that are valued identically, except that $X is close to zero. $X + $Y + $Z = a huge net positive value (judging from the number of HN comments and votes, as well as the pride that OP shows in the writeup). For many of these Show HN posts, it doesn't matter if $X is $300 or $0; the math still evaluates to awesomeness.

I'm not sure I follow. My criticism is in trying to value projects in term of engineering time. I don't think that's valid at all. Free time is worthless, except to the person spending it. It's not like I'm going to spend my free time doing more work for my company and make that much more money at an hourly rate: I'm salaried, so extra time spent is just a gift to the company with the vague hope I'll get some bonus or promotion. Plus, for mental health I have to take breaks from work and do something different, which could be reading a book, watching a movie, or working on a personal project completely unrelated to work. Either way, I'm not counting that time in terms of an hourly rate; I think that whole concept is just insane. I don't think of the time I spend on the toilet or making dinner in terms of an hourly pay rate, so why would I do that for a personal project? The only cost to me to pursue a hobby is in the materials needed.

My mistake was using typical prices for engineering work as an attempt to establish a baseline understanding that we all agree free time is very valuable. I can see how that's become a morass in this discussion.

I value my own free time much more highly than I do my employment time. I would prefer to have more free time than employment time. So if employment time's going rate is $X, then a dollar value of free time must be higher than $X. No, I don't expect people to pay me for my free time. But I do think it's healthy to think of free time as the most valuable time someone can have. Not the highest price but the highest value.

This is why I think it's wonderful to see projects on HN where we find out how our fellow geeks are spending their most valuable time. And it bugs me that people sometimes respond that someone could have bought the same thing for less money or less time.

Ironically, we both object to putting a price on time, but I believe our objections are in opposition to each other.

Yeah, I think we're agreeing but in different ways. I think of my free time as mostly worthless to others, but infinitely valuable to myself, so I refuse to put a dollar value on it.

And sure, I agree that it's nice to see people spending their most valuable time doing something they enjoy, in this case interesting projects.

But as I've said elsewhere, personally, I wouldn't spend my time making a copy of something I can just buy a better version of cheaply elsewhere; if I'm going to spend my time on a project, I'd rather spend my time doing something different, like something new or a customized version of something, which I can't easily buy. But it's not black and white; I'll happily spend my time fixing my bike instead of paying someone to do it, for instance. (Of course, paying a professional might take more time once you consider how long it takes to bring the bike to them, and then wait a week for them to get to it...) I like fixing things like that, so for me it's enjoyable.

Software projects have portability; you spend X amount of time, and others can use your labor for free or nearly free.

In comparison, hardware projects have costs even if the 'hard work' is done: PCBs to buy, components to assemble, parts to purchase. Even BEST case here, and discounting peoples time, it looks like the cost of all the components listed would be in the neighborhood of $200. And that assumes you can source the same 'demo' cable that the OP purchased for the same cheap price. Realistically I bet actual costs would be $300+

I have nothing against DIY hardware projects, the problem is that hardware projects must pass a much higher bar: you have to be cost competitive at a minimum with existing products on the market, or you need to be better in some way (and, that way can be trivial, as long as it's interesting). This appears to be neither.

Because the project makes the claim that it was to save cost. The reality is that most of the cost is in paying an electrician for the install, and since he did that part himself anyway he could have just went for an off-the-shelf certified charger.