Hello there!
I’m developing a game for a school project, and I need some help for a problem that might just
be super simple.
I have an image that could help explain the situation: Imgur: The magic of the Internet
First of all, the player is ONLY able to move on a Vector3(0,0,1), and is able to rotate 90 degrees to either side. These are not smooth moves, but it is a constraint that is intended. However, this makes collision detection with triggers imposible (I guess, because they seem to not work when I tried).
Second, the thing is that I need to be able to detect when the player is standing near the ‘Clock’ in the image above. I need to be able to perform an action when the player is at the ‘Clock’ in the scene.
As stated, this cannot be done by using collision detection. I’m not sure if raycasting will work either.
Anyone have any ideas?
Thanks in advance! 
I do not see why moving a player forward and rotating it with 90 degrees would make collision detection impossible. Do you have a rigidbody on your player because in order to have triggers work you will need a rigidbody on one of the two objects.
You can use triggers. Why wouldn’t you be able to, just because your movement is constrained? As long as you end up touching the trigger, it’ll work, unless you’re missing a rigidbody, etcetera. It’s not going to stop working just because you choose to move in certain increments. Instead of choosing not to use a major part of Unity for its intended purpose because you can’t get it working, you should try to figure out if you’re missing something. 90% of the time Unity will be able to do what you wanted it to and you just missed something. You can’t say “collision detection doesn’t work” unless you understand WHY. If you don’t understand why, then you don’t know for sure it can’t do it. 
Also, you might want to fix that null reference exception. 