# PRU firmware for HC-SR04 rangefinder HC-SR04 driver that can be used with BeagleBone Black ## Install PRU C-Compiler 1. `sudo apt-get update` 2. `sudo apt-get install ti-pru-cgt-installer` ## Rebuild rangefinder.c 1. `cd ardupilot/Tools/Linux_HAL_Essentials/rangefinderpru/` 2. `make`