Here’s a cool ethernet-enabled mechanical hit counter. It seems kind of over-powered using a relay but this can be a great source of information for similar applications.
So, when you ping salem, you’re actually hitting my firewall, which redirects ICMP type 8 (Echo Request) so the board, whose internal address is 192.168.0.2.The BX decodes the ping request and asserts a TTL output high for 50ms. This turns on the transistor, which fires the relay, which cycles the power, which increments the counter. Then, the webcam takes a picture of it every 5 seconds and stores the image in the www directory. Voila!