If you want to learn a functional language, Lisp is a good choice. It has been around a long, time, so it is stable and well supported, and it is also the basis for many other languages. Haskell, while also an excellent language, is more niche.
Deciding whether to learn a language or learn how to write a compiler is more difficult. If you are struggling with the Dragon book, have you condidered "Modern Compiler Implementation in ML"? Although ML is even more niche than Haskell, it is a functional language and the book takes you step-by-step through the process of writing a compiler for (a subset of) it.
Great quote: "Danish computer scientist Bjarne Stroustrup invented the C++ programming language in 1978, taking the C language invented by the late Dennis Ritchie and adding new features that made it more usable by the masses. “
In short, we can't extract more than about half of the available wind energy, no matter what the design.
This is because if all kinetic energy is extracted, the air would no longer be moving behind the windmill, so it would stop turning. Betz's law is the optimum compromise between extracting energy and sufficient airflow to keep the windmill rotating.
If you don't need Windows or the mobility, a Raspberry PI 2 may be an alternative. They are about $35 plus tax and the model 2 is as capable as a five year old Laptop.
I think this might be the relevant change (contained in bill S-1 which was substituted in the Regulatory Reform Committee):
"2 (i) Sell any new motor vehicle directly to a retail customer
3 other than through <del>its</del> franchised dealers, unless the retail
4 customer is a nonprofit organization or a federal, state, or local
5 government or agency. This subdivision does not prohibit a
6 manufacturer from providing information to a consumer for the
7 purpose of marketing or facilitating the sale of new motor vehicles
8 or from establishing a program to sell or offer to sell new motor
9 vehicles through the <del>manufacturer's</del> FRANCHISED new motor vehicle
10 dealers THAT SELL AND SERVICE NEW MOTOR VEHICLES PRODUCED BY THE
11 MANUFACTURER."
The first use I know of that gained wide recognition was in Kernighan and Ritchie's "The C Programming Language" from 1978.
"1.1 Getting Started
The only way to learn a new programming language is by writing programs in it. The first
program to write is the same for all languages:
Print the words
hello, world"
I find it interesting, because K&R seem to assume that this was already a standard approach, and also because of the comma after hello. In my first attempt in a new language, I don't think I would be paying that much attention to grammar...
First and foremost, congratulations on a wonderful piece of art. The realities of accounting should not distract you from the fact that the project was a success and enriched people's lives.
Although you paint a pretty bleak picture of the finances, as others have pointed out above, this does not reflect the economic reality.
The typo impacted your profit margin significantly - without it, you would have had an additional $7k and a margin of 19%.
But this is only a side show. Even if you had made 0% on the posters shipped to the Kickstarter backers, the 800 posters remaining represent a book value of $96k. (Less a few hundred dollars for storage).
Assuming you can sell at this price, your three years work will be amply remunerated for a part-time project.
In the end, Kickstarter functioned as it should. It reduced your risk by providing a pool of known buyers and left you with the infrastructure for approaching your market. That market is your final reward.
It would have been interesting to see the power consumption compared. The Raspberry PI model A can be operated below 0.5A, in some cases 0.25A, which makes it attractive for mobile installations. How do the other two boards compare, do you know?
Deciding whether to learn a language or learn how to write a compiler is more difficult. If you are struggling with the Dragon book, have you condidered "Modern Compiler Implementation in ML"? Although ML is even more niche than Haskell, it is a functional language and the book takes you step-by-step through the process of writing a compiler for (a subset of) it.