I want to share folowing project with the community.
Do to the covid pandemic my students are using this as a context for their programming context.
They are going to build a gate to controle the amount of people that can enter a building (restaurant, amusement park, public library, …)
Because today there are also a max visitors allowed in stores, and many other buildings they started with a counter and sounding an alarm if the max capacity is reached.
For doing that we used the VMA209 shield because it has a 4 digit 7 segment.
The reset functionality is because some facilities have 1 in and another exit. There the rule can be X persons every 30 min allowed in.
The program is available here : http://olc-stem.be/ARDUINO/VMA209.ino and i have documented every line of code in the English language.
Also for students its a nice example of edge detecting the buttons instead of signal detecting.
and setting priority between multiple buttons when pressed simultanious.
If there are questions, you can ask here.