HC-SR04 and FreeBSD

[Evandro Nunes]

hello,

ive got a ultrasonic sensor model HC-SR04 and a beaglebone black as well as
a cubieboard2, both running FreeBSD 11 built from crochet and wiki
instructions

thanks to the help from loos@ I could manage to use a 5v relay with BBB
now, how can I read data from HC-SR04 sensor? do we have any library
available? or do we have any GPIO utility to do that?
btw how can I read values from GPIO pins when they are set to input?

thank you all in advance