Had a number of people come through my room the other day and I was asked to add a little more to what they observed.
The Middle School class you observed today is an example of how a micro-controller, the Hummingbird Duo, could be used as a simple output device as part of a lesson with a goal of teaching procedural programming. Procedural programming involves organising code into smaller more clearly defined parts which help with organisation, code clarity and program size.
We looked at creating the Morse Code equivalent of S (Step One). We continued to look at
building the morse code sentence “Help I am lost at SSIS”. This lead to a long set of blocks that defined the sentence.
The students then went to the next step and using More Blocks defined the LED morse code for Dot and Dash (Step 2).
Once this was defined the creation of the block needed for the LED morse code was simpler and they were able to create the S block (Step 3) and the rest of the sentence.
Some then noticed that this code can also be expressed using a repeat command to further simplify the code (Step 4). 
I also really like that it becomes easy to differentiate assignments. While most of the students were working on a message I provided “help I am lost at SSIS” students who completed this then created a program where a user inputs a message and the program then creates the morse code for any message provided. A much more difficult task.
The video below shows a student that attempted the more difficult version. There are still some parts that need work and the red undefined errors will change when we add the hummingbird blocks.