This project uses an ultrasonic range finder and an LED display module to count people moving past the range finder and display the number (Figure 9-1).
FIGURE 9-1 Person counter.
This project uses a Protoshield and an RGB LED to indicate status and a power MOSFET transistor to switch the 12 V needed by the door latch.
To build this project, you will need the following:
Figure 9-2 shows the ...