There were three jumbo LEDs on board the boat. There was a red, blue an a green LED. The red and blue LEDs were used to indicate which team the boat was on and when the boat had been matched to a helm. The green LED was used to indicate when the iButton was read successfully.
The LEDs were driven off of 5 V using a 2N7000. The 1K resistor between the signal line and ground was used as a pull down to pull the signal line low when not in use.
