hi, can anyone help me?
i have project that must detect ship that enter or exit port
and the gate's length is 100m
do you guys have recommendation what sensor should i use?
thank you for your help
That’s a very specialised task , you need to see how others do it and expect it to be expensive .
Is this a real project ?
yes it's real, i ordered to make it happen
i mean, can i make it simple?
my assumption is it's like detecting car in/out from park gate but in large scale? cmiiw
How many ships can go through your 100 meter gate at the same time?
Paul
i mean, can i make it simple?
Yes, buy a suitable commercial beam break detector (photogate, range finder, etc.).
There are a number of LASER sensors which will well exceed 100 yards. I would contact a company like Micro Epsilon or similar and talk with an applications engineer. Explain the full scope including can, for example, two ships be passing in the night at the same time? You also need to define "ship". Most major ports know what is coming and going and when.
Ron
Paul_KD7HB:
How many ships can go through your 100 meter gate at the same time?Paul
the smallest boat is 3m length so i assume almost 10 boat can enter the gate at the same time
A 100 m gate? Detecting ships coming and going. One sensor, one static laser beam will do nothing. You need at least to scan a sector. That's what radars do, right? Having a radar image of the port, then performing some image analysing. That would get the job done, right? I mean, that system could report like "1 ship coming in, 2 fishing boats going out". A static laser beam could report "37 m to object".
Johan_Ha:
A 100 m gate? Detecting ships coming and going. One sensor, one static laser beam will do nothing. You need at least to scan a sector. That's what radars do, right? Having a radar image of the port, then performing some image analysing. That would get the job done, right? I mean, that system could report like "1 ship coming in, 2 fishing boats going out". A static laser beam could report "37 m to object".
for image processing, can you tell me what sensor should i use for that scale of gate?
Johan_Ha:
A static laser beam could report "37 m to object".
I found a laser distance sensor, which can measure up to 50 m. But the specs said nothing about how narrow the beam sector is. You won't get a very sharp image from info like "there's something at 37 m distance, inside a 10 degree sector". But if the sector is only say 2 degrees, you can perform a say 60 degree scan, measure distances at each one degree. Add some logic and you might get to recognise different vehicles and their directions.
I would do this with an Arduino, maybe a Raspberry Pi, and some sensors, if I thought it would be a great challenge. But if I really needed this, I'd buy commercial products based on radar technology.
sessium6e:
the smallest boat is 3m length so i assume almost 10 boat can enter the gate at the same time
When you have solved this counting problem, you have solved the rest of the problem.
Paul
sessium6e:
the smallest boat is 3m length so i assume almost 10 boat can enter the gate at the same time
I was thinking ships as in large ships and now we have row boats tossed into the mix which are maybe a meter or two above sea level and no clue if there is any tidal change. I envisioned large ships entering or leaving a large port area not tiny boats. 
Ron
As per my original post - not easy ; or if actually possible !! detecting the ship is not the only issue; you need to know which direction it’s going in , multiple hits as it bobs up and down, not detecting birds etc etc etc
I’d suggest you google “ port security “ or similar - it’s not an Arduino type project , and won’t be possible for a few $$
In a marine environment all sensor/electronic systems must be fully hermetically sealed using marine grade cabling otherwise the salt will pretty quickly cause problems. This means a professional sensor system designed
for the task really.
In the real world, port control uses transponders in the ships that respond to the port radar sweep. The OP must not be in an area with inclement weather.
Paul
A already built navigation radar. Something that would assign designationtors to separate moving bodies and track those bodies. The navigation radar can use stationary objects to create a LOP grid to determine objects relative positions and direction/SOG (Speed Over Ground) of travel. Cost of a pre-built unit should be around 4,000.00 USD or, if you build your own, millions.
USD4k? Didn't expect it to come that cheap.
Those small dingys will still cause problems - unless you can be sure they're all carrying radar reflectors so they're visible.