So I needed to find a way to help park my wifes car into the garage in the perfect spot every time so I could still work on my tool bench when needed. I didn’t want a ball on a string in the middle of the shop for when the car is outside and I am trying to cut down sheets of plywood. So I came up with this, I call it the Align and Park tool. Basically, its two top layer floating lines and one back layer stationary line, when you are in the perfect spot you mount them aligned at eye level (front car) on the side wall. Then when you are pulling into the garage the lines are not aligned until you get into the perfect alignment (spot). It is hard to show how it works in photos so I made a full video and example of how it works down below too.
Hmm, clever use of parallax. I suppose your head position matters, is it sensitive enough that you have to do something like lean your head on the headrest to be sure it’s in the right place, or is there enough wiggle room that it doesn’t matter too much in practice?
There’s a little wiggle room since the lines are engraved a little thicker. I just recommend mounting it eye level where you normally have your head position when driving. Obviously if you want it the same Everytime then just mounting with your head back against the headrest would be best.
Useless Trivia: We used the same technique with two lights for beach landings. The front light was a meter above the ground and the rear light was two meters behind the front light and two meters above the ground. If the two lights appeared vertically aligned from the ocean point of view, the boat operators (coxswain) knew they were coming in along the approach path.
Airplane pilots use a similar system called VASI to determine if they’re on the proper glide slope to land on the runway vs coming up short or over flying the landing and potentially run out of runway.
There are (usually) 2 bars of lights separated from each other so that when on the proper glide path (generally a 3 degree slope) the lights line up correctly. The top of the light is white and the bottom is red.
If all the pilot sees is red, then he’s coming in too low and will not clear the threshold. AKA, controlled flight into terrain.
If he sees all white then he’s coming in too steeply and will also likely punch the ground except at least he’ll have made the runway
If he sees white in front and red in the back he’s on the line, will clear the fence and land on the runway where if he flares correctly he will just glide to a touchdown.
Nice, Much more artistic and high tech than my grandpa’s method of hanging a ping pong ball on a string precisely measured to touch the bottom center of the windshield when properly parked.
I’ve just been going for higher tech, less artistic, more lazy: with a lot of recent cars having ultrasonic parking sensors, I just stop when the dash says I’m 30 inches from running into my Glowforge workbench.