I am in a high school in San Jose, CA and have a mix of 9-12 grade students in the 3 classes that I teach this. The class is comprised of students from the highest achieving at the school to the lowest.
This lesson ran well as written.
I have run this lesson with one section of the class and let a sub handle two sections of the class.
The warm up is really quick and students remembered the animal cards from the day before.
It was easy to say that computers use only two cards. The students really accepted that you can only use two cards. Many of the students gave me a 1 or 0 when I said that computers only use two. The concept that it really is electricity through wires is a bit strange to students but that is a deeper concept that can be explored with some extensions to the material(if you want)
Students cruised through the hidden messages pretty easily and made their own messages.
The first three lessons took me a week and I felt that this was a good place to check for understanding.
I had the students write out what were the take aways from the first three lessons. I have not checked back with them but will reply later with some feedback about what they came up with.