Ultrasonic for Parking control solution

Hello everyone.

So I'm trying to make this project for controlling a parking (there's a narrow L shaped ramp where entering and exiting vehicles can't enter and exit at the same time and don't have good visual, the idea is to light up stop and free to go LEDs to let people know when a vehicle is entering or exiting)
I was suggested to use SRF485 sensors, mostly because of the distance of sensors and the microcontroller (~20m) to have a reliable communication. The problem is I looked into the technical specification page and found out there's very little info on how to code for the sensors. I also couldn't find any library for any sort of microcontroller.

Now, should i use other sensors? because the main benefit of using SRF485 seems to be being able to put many sensors on a common bus, but I'll need 2 or max 4 sensors. on the other hand, I donno if using a let's say SRF05 I can communicate between the uC and the sensors (because of the distance).

I'd appreciate any suggestion or help.


Thanks in advance
Cheers

Basically SRF485 is a ultrasonic sensor Module with Ultrasonic Sensor + Microcontroller + 485 communication IC.

So if you are having trouble in using SRF485 you can use SRF05 some come controller like Arduino and a TTL to 485 Converter Module or MAX485 IC which will measure the distance and send it to your Main Controller.

You will not be able to communicate directly between your uc & SRF05 sensor directly because of the distance.