We wrote the codes necessary for the HC SR04 Distance Measurement with the FPGA on this video. We created a project with Quartus. We performed the steps in turn. We made our pin planner according to the pins of Altera De0 Nano.
Code: https://goo.gl/kmgQqP
Note: On the first video, use the GPIO01 pin instead of the GPIO02 pin. I wrote the first video wrong.