design a device that recognize when car enters garage and controls video output

I would like to automate the process of rotating images from three cameras on the same TV screen using a HDMI router (that I already have and control with a remote control). Basically I have three cameras each focused on different areas (one on a table that weights the axle, one on the front wheels and the last on a front bumper impact protection area). When I enter the garage I have to position the wheels on the weigher and read the value, then I forward slowly with care not to hit the bumper with the wall. I use a HDMI router with remote control to rotate the images. But sometimes I forget about the remote and I have to go back for it. It is annoying. Also if it gets lost we have problems. So I would like to invest in a software/device that recognize the position of the car as it enters the garage and covers some markers on the floor. Camera sees three markers, image 1.Camera sees two markers image 2. Camera sees no marker - image 3. The router accepts serial commands. I have medium skills in electronics and device design. I assembled a 3d printer and made various Arduino projects ,but a task like this is above my skills and time. Also, cheep light barrier solution that is easy to design and I could do it myself would not be, for various reasons, accepted.