If it is a hobby who cares about ethics, right?
Ok. Can you please articulate the ethical rules that my post violated. The only thing you mention is "maybe someone could use few $", so I'll address that.
Every dollar that "someone else" makes in this circumstance is a dollar that bmanthey pays. So it's ethically neutral from that POV, unless this "someone else" somehow
deserves the money more than bmanthey. Now for all I know, bmanthey is doing his pit-stop challenge for poor crippled children, working in a freezing garret on his hobby during his few hours between 10-hour shifts at Mr Scrooge's dickensian insurance adjusting sweatshop. Meanwhile, this "someone else" might have a resume dishonestly padded out to a mile long and knock the project over in 2 hours like I did and charge two full days work at $100/hr.
For all I know.
Another possible ethical violation is that I am setting the price low for everyone else. That I am what trade-unionists term a "scab", here in Australia. Well, what you are proposing is that we here on the arduino forums engage in collusion and price-fixing, which is not only dishonest, but in some places illegal. I'll make this exception: trade unionism and solidarity is moral and just when you are fighting large companies that hold a monopoly over employment and use that monopoly to create unfair working conditions. I don't think bmanthey fits the bill.
Another objection is that my doing this for fifty bucks might discourage the young-uns who might think of making a career coding up microprocessors, who would have been able to add this job to their resume and also earn some pocket-money. I have denied them their first taste of earning actual, sweet sweet moneys for their craft.
This, to me, is the most serious objection, and the thought of it does indeed give me a twinge of guilt.
All I can say is: kids, you are not going to be able to make a living coding up one-off personal arduino projects for dudes on the internet. You are certainly not going to be able to charge $100/hr for it. This may be a brave new world of internet enterprise, but you are almost certainly going to need a
job, working for an employer, and doing regular hours. At least at first. In a world where kids are building actual robots in high school, flashing some lights in sequence doesn't really cut it as commercial experience. Those kids who are honestly excited about programming and robotics, and those kids with a knack for entrepreneurship - they won't be put off by this.
Finally, my motivation for doing this was partly vanity. Yes, yes! You're right! I confess - I did it to "be a hero". Does that make my actions wrong? Maybe. At least, to the extent that it does.
But my motive was not entirely vanity: a large part of it was to show people how to use object oriented coding in the context of microcontroller programming, to showcase the principle of
encapsulation. Not every arduino program needs to be a rat's nest of globally declared variables. I did this to show people how I think it ought to be done. When a bloke gets to be a certain age, he gets an urge to teach. I think it's instinctive.
So ok, maybe I did a bad thing. But when I think about those crippled orphan children's precious faces lighting up as they do their pit-stop challenge, I think that maybe I didn't.
On balance.