I started this project mainly as a segway into teaching myself more about the MSP430 family after I was inspired by a college course in embedded systems last year. We learned how to program the family in C++ and Assembly, but really only scratched the surface. It has been a challenging yet fun project and has helped me veer away from the Arduino.
So without further ado, here's an explanation of what this Instructable aims to show you how to build:
The room visitor counter (as you might have expected...) counts how many people are currently in the room, given this room only has one means of entry. We're not talking firepoles here - I mean a doorway. When there is at least one person in the room, the relay is switched on. And vice versa, if the room is vacant, the relay is switched off.
Using 3 blue LEDs, there is a binary count (I didn't have a 7-segment LED display/display driver at the time I built this) of how many people are in the room, with a maximum displayable count of 7 (when the count is incremented past 7, the LEDs simply remain on).
In this instructable, I assume a level of ability in soldering and prototyping skills. The detail in this instructable is on a higher level of abstraction. In other words, if you can solder, read a schematic and are comfortable downloading some software, you can do it!