The entry in the book is perhaps a little too easy for my taste (along warn the author that it will be easy for engineers ...). The explanations as and as we advance in the reading are good. notably on how to avoid certain pitfalls of working frequency of the micro-controller and the use of physical components such as switches. There are little tricks that I had not suspected. I wish that the circuit diagrams are diagrams rather than drawings. Or at least have the 2. Finally, I am a little left hungry compared to explain the code of the proposed programs. Especially at the end. Some functions are used without explanation and if we want to go all out in understanding the code in question, consult other resources.
In any case, all reads very easily and very quickly. For the price, this is a very good first reading on Arduino.
