# Home Made Laser transit On The Cheap??



## Atomic6 (Apr 9, 2010)

I need to level a grade. Has anyone set up a laser pointer to fabricate a makeshift transit before? Don't need anything too fancy-just trying to level the dirt in a 100 foot long garden plot. I have a 6-foot aluminum scale, a few tripods, a couple greenie pointers. I just need plus/minus 1" accuracy. Figured taping a pointer to a 3 foot level (leveled) on the ground should get me near level 100 feet away?

Don't really wanty to spend $275.00 for low end mechanical/optical transit and not even $800 for a laser transit for occasional use like this..

Any tips appreciated.

Thanks


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## 65535 (Apr 9, 2010)

You'll want to level the beam, which unless you live near a black hole will be very straight.I would set up the level perfectly level, then with a piece of paper bent 90 degrees test the laser on an adjustable mount so that when the paper is at the far end of the level the beam is the same height as the near end. That should be pretty darn close.


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## HobbyLaser (Apr 10, 2010)

While green lasers are typically more visible than red, they do have one characteristic that could pose a potential problem for your specific application.

Because of how they operate, oftentimes the beam will come out at a slight angle from the body of the laser! While this is not a big deal for just messing about, it could obviously cause problems if you were trying to use a offskewed beam for leveling at a distance.

I would therefore advise that you first check the laser you intended to use for this purpose, against a known good level surface (or already accurate transit level), to see if the beam is actually straight or not! If not, you might try rotating the laser so that the beam skew is 90 degrees offset from the direction you wish to measure (i.e. - if you want to measure up/down/level, then align the laser so the beam skews to the right or left).

This skewing is a result of the beam refracting through multiple crystals (which are aligned by the manufacturer to get the best beam quality, *NOT* the straightest beam), and is a fairly common (but not universal) problem with green laser pointers. It is not an issue with diode-based lasers, such as red (or even BluRay) ones, so those type of laser pointers may prove more accurate for this type of usage.


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## Atomic6 (Apr 11, 2010)

Thanks for ther replies. I think that I will attempt a jerry rigged greenie taped to a 3 foot aluminum level and see if I can get it to read level a distance away. If that works in the shop-I'll take it outside and try to measure grade.

My plan B is to purchase a " Watrlevel " brand water level; sinc3e they look like thaey have worked out the bugs and have features hard to beat for the price if you tried to build one yourself for a one person operation. The price is 1/5th that of even the most basic optical transit. 

Still open for suggestions.

Thanks


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