Help an oyster farmer

[Caju Barbosa]

Hi to all, I'm an oyster farmer looking for a lazer to be used as a level for putting poles in the water. The idea is to have the laser levelled on a pole and as soon as the dot disappears on the second pole we drop the second one and on and on ( I need a lien of poles all levelled and spacing 7 meters from each one for 400 MTS...
The ideal is to bee seen against a black pole in sunny bright day. ( green?)
Need to be seen in minimum 500 meters (200mw?)
And the one I couldn't find need to be on for at least 3o minutes ideally 1hr
Is this achievable?
Thanks all. Can post pictures once I get this going

 

[steve001]

Hi to all, I'm an oyster farmer looking for a lazer to be used as a level for putting poles in the water. The idea is to have the laser levelled on a pole and as soon as the dot disappears on the second pole we drop the second one and on and on ( I need a lien of poles all levelled and spacing 7 meters from each one for 400 MTS...
The ideal is to bee seen against a black pole in sunny bright day. ( green?)
Need to be seen in minimum 500 meters (200mw?)
And the one I couldn't find need to be on for at least 3o minutes ideally 1hr
Is this achievable?
Thanks all. Can post pictures once I get this going

Possibly. I would approach it from a surveyors perspective by attaching retro-reflectors on each pole. There are $$$$ lasers that run continuously.

 

[perfo]

Might be a silly question but can't you use the surface of the water to measure from? You have a ready built spirit level?

A cheap laser can run for hours, as it purely depends on the size of the battery and the cooling which with a low power laser wouldn't be much. My experience (which isn't that great) is when you get to those kinds of distances you either have a big spot size and thus lose accuracy and brightness or a small bright spot that you can't find. With a small spot you'd need a big target to see where the laser is and then adjust from there. One thing you may be able to do is to put a laser detector on the first pole and carry the laser with you. Mount it on a rifle scope and bi direction levels that way you can sight the target and get the laser near then set the height of the pole when the spirit level tells you, you are horizontal..

 

[Caju Barbosa]

Might be a silly question but can't you use the surface of the water to measure from? You have a ready built spirit level?

A cheap laser can run for hours, as it purely depends on the size of the battery and the cooling which with a low power laser wouldn't be much. My experience (which isn't that great) is when you get to those kinds of distances you either have a big spot size and thus lose accuracy and brightness or a small bright spot that you can't find. With a small spot you'd need a big target to see where the laser is and then adjust from there. One thing you may be able to do is to put a laser detector on the first pole and carry the laser with you. Mount it on a rifle scope and bi direction levels that way you can sight the target and get the laser near then set the height of the pole when the spirit level tells you, you are horizontal..

Good one unfortunately the tide moves up or down and we need to drive about 100 posts with post driver. That's how we do at the moment. But tahn u have wind and I was trying to get a better job done. I could get away with maybe 200 MTS. And keep moving the laser. The ideia was to drive the post until the laser dot is above it. Clearing for the next one. If makes sence. Any suggestions for models

 

[perfo]

I haven't really a suggestion as to a laser (though lots of folks on here may have) I'd try a dirt cheap thing first whatever you can get locally. Getting 200meters is easily achievable but as I mentioned before , finding the dot on a moving boat may well be your problem a slight move up down or not perfectly in line and you'll spend ages looking for it.. One that is goin got be very bright in direct sunlight is do able but probably too powerful to be safe to be firing randomly as a constant beam. Any chance someone could be left at the last post knocked in and they could aim it with some sort of scope ? If you are capable of a bit of basic electronics with two motors and mirrors you could produce a cone shape to the laser beam that starts off maybe 2 meters across ( at the expected distance) then gets smaller until it hits the center and back out again.. This would help tremendously trying to locate the beam..

 

[Caju Barbosa]

I haven't really a suggestion as to a laser (though lots of folks on here may have) I'd try a dirt cheap thing first whatever you can get locally. Getting 200meters is easily achievable but as I mentioned before , finding the dot on a moving boat may well be your problem a slight move up down or not perfectly in line and you'll spend ages looking for it.. One that is goin got be very bright in direct sunlight is do able but probably too powerful to be safe to be firing randomly as a constant beam. Any chance someone could be left at the last post knocked in and they could aim it with some sort of scope ? If you are capable of a bit of basic electronics with two motors and mirrors you could produce a cone shape to the laser beam that starts off maybe 2 meters across ( at the expected distance) then gets smaller until it hits the center and back out again.. This would help tremendously trying to locate the beam..

The laser will be static on one pole. Pointing in a direction where all the other poles will be aligned as we drive the pole in the sea ground. The dot will move up until it clears. We got that pole levelled and clear to point on the next pole 6 MTS away... My concern is about the power as it need to be strong enough to see. But not to strong to burn some loose hands
Could u suggest a model or specs so I can chace it

 

[steve001]

I think I gave you a workable idea. You could do a dry run and I do mean a dry run on land. Attach a retroreflector to a pole and mount a laser to a tripod. Now walk away from the laser to the first distance. Shine the laser on the retroreflector. Repeat. Note the results. You will need a helper.

 

[Philipnzw]

I think I gave you a workable idea. You could do a dry run and I do mean a dry run on land. Attach a retroreflector to a pole and mount a laser to a tripod. Now walk away from the laser to the first distance. Shine the laser on the retroreflector. Repeat. Note the results. You will need a helper.

I think Steve is on to something here. Retroreflectors are definitely the way to go. Would negate the use for a strong laser (tons of disadvantages to using a strong laser).

 

[hakzaw1]

green lasers are the easiest wavelength to see--day or night.
Since it appears that you will need a well heatsinked laser to avoid over heating'

so look at lab greens that have a fan and can run off a 12 vdc battery. not expensive.

Focusable 12V 200mW 532nm green laser module continuous work / long life / TTL | eBay

Focusable 12V 200mW 532nm green laser module continuous work / long life / TTL | Business & Industrial, Healthcare, Lab & Dental, Medical/Lab Equipment Attachments & Accessories | eBay!

www.ebay.com.sg

^^ this one can run a long time-- BUT salt air and water- could be a problem- maybe make a 'housing' that protects. It has more power that I think you need..
but better too much than too little.

It may be able to run until the battery(s) needs re-charging-- hope this helps- we love to see any pics.

those aaa little pen lasers cannot run very long. The red ones may last longer than the others..but for <$3 usd it is no big loss--a cheap 'bubble' level might be good to have.. also very .cheap

hak



BTW I got 6 fresh oysters but my girlfriend said that 'only 3 worked' <its a joke)

 

[RedCowboy]

The laser will be static on one pole. Pointing in a direction where all the other poles will be aligned as we drive the pole in the sea ground. The dot will move up until it clears. We got that pole levelled and clear to point on the next pole 6 MTS away... My concern is about the power as it need to be strong enough to see. But not to strong to burn some loose hands
Could u suggest a model or specs so I can chace it

Be aware that any laser over 5mw can cause eye damage so if peoples " loose hands " are going to be in the lasers path their eyes won't be far away, you must not let any laser over 5mw be able to strike a persons eyes, you don't want to create a hazardous condition where an accident can happen.