To answer some of the comments:
The laser pointer is mounted on brackets to allow side-to-side and up-and-down adjustment, and is mounted on the garage ceiling approximately 3 feet in front of the car so that adjustment can be made (on a stepladder)with the car in place. The beam is aimed so that when the car is in its proper place, it shines through the windshield and hits the middle of the dash. Select a metal-cased pointer - cheaper plastic-cased units do not dissipate heat and since my door opener light is on for approximately four minutes, so is the pointer. Laser pointers have a built-in diode to prevent damage in the event batteries are inserted backwards. Thus, when applying the dc power, depending on the polarity of the connection, either the pointer will work or it won''t. If it doesn''t, simply reverse the wires. Regarding the pot, before applying any power, use an ohmmeter and adjust the pot to its maximum value. Then, after connecting one or more pointers, connect the power and adjust the pot to yield 3v. This system has been in use in my garage for approximately six months and has worked perfectly every time. And yes, this is not recommended for households where there are children. Finally, wall wort and wall wart seem to be used interchangeably. Both can be found on the Internet to denote a plug-in low-voltage power supply.

interestin topic...

great article.

Where does the laser point (car hood, bumper)? Where is it mounted (ceiling pointing down, wall pointing side ways, floor pointing up)?

How does it tell you the car is in place?

Greetings,

I live in an area where power failure is a daily occurance. Plus, I do not have a garage door opener. I use two tennis balls to remove parallex and correct for distance as a single ball touches windshield.. How does you gadget over come my problems?

Sincerely,

Tom Grosch

e-mail: tgrosch@cox.net