It's a three year rotation: Python, C (Unix), C (Arduino). My goal with the class is to teach ideas that will stand the test of time. C (and Unix) certainly fit that bill.
Happily, the tooling is the easiest part. Every student has a rasberry-pi running debian, no mouse, no window server, and no extraneous software. You can spool kids up on a nano-based C toolchain in one class period with remarkably few sharp edges. There's even some fun accidental learning the first time they nano their executable file.
Neat! I think your choice of C and Python as the languages to be taught is very right. The idea of showing the use of C in both Desktop/Server and Embedded environments has long been the approach i had advocated. C is truly the de-facto "universal" language and students should be made aware of it from the start.
I would suggest the following additions;
* The Arduino "language" is C++. Use this as a gentle introduction to C++ as a "better C". From there you can move on to proper C++ (do NOT teach "Modern C++" in the beginning). The intent is to show how "C + some syntactic sugar for expressing abstractions" is quite powerful and that is what is C++. This should prepare the students to embark on a proper study of C++.
* Instead of using the Arduino "language+library" through the IDE, show them how to use the same GNU gcc toolchain to program the MCU directly in C. See Make: AVR programming by Elliot Williams for details. This teaches the students the idea of a "cross compiler toolchain" and all other related matters from first principles.
C++ is the language with which I’m most comfortable, having used it professionally for the better part of a decade. I’ve gone back and forth on using it in HS. It’s abstractions are so opaque if you don’t already have a well developed model of programming.
For the arduino, I’m really interested in teaching control systems. So we will start with finite state machines and go from there to implementing PID controllers. I’m intrigued by the idea of avoiding the IDE, so will totally pick up that book!
Happily, the tooling is the easiest part. Every student has a rasberry-pi running debian, no mouse, no window server, and no extraneous software. You can spool kids up on a nano-based C toolchain in one class period with remarkably few sharp edges. There's even some fun accidental learning the first time they nano their executable file.