Post by thread:[OT] proximity detector

I wonder if anyone can help. I have an application where I wish to photograph a boat and people at night (IR camera) but need to be able to detect that they are there and in which direction (so I can point a camera at them). This is to monitor offshore property. I need to get a range of some 100 metres reliably. Hydrophones have been suggested but I am concerned about directional capabilities and possible interferences. Does anyone have any ideas in this field? TIA, Peter Grey Neosystems

>some 100 metres reliably. Hydrophones have been suggested but I am concerned >about directional capabilities and possible interferences. Does anyone have >any ideas in this field? IR sounds like it would indeed be functional, especially if you use the IR sensitivity of a CCD as a starting point. Andy \-----------------/ \ /---\ / \ | | / Andy Kunz \ /---\ / Montana Design /---------+ +---------\ http://www.montanadesign.com | / |----|___|----| \ | \/___| * |___\/ Go fast, turn right, and keep the wet side down!

The German magazine "Funk amateur" january 1999 issue has an article on how to build a "private radar". It uses the KMY-24 from Siemens (priced around 100 DM). It works at 2,54 GH. The interface circuitry is build using 10+ "discrete"(no mcu's) ICs, and uses a ICM7217 to display distance or speed. Caveat: max. detectable distance is 8 m! :-( But perhaps Siemens has other and better units ? -cp {Original Message removed}

Low-tech solution: Black Polypropylene rope floats on water. Let them wrap the stuff around their propeller shafts, pulling a bend in the rope out of a clothespin type clamp switch that turns on an alarm, and likely they'll still be there when you get there, trying to figure what went wrong with their prop. I Scuba dive, and in the search and rescue group I was in, one other member was having problems in the Hood Canal area with some bozo playing slalom at full speed around her basic open water class students with their fast boat, "diver down" flags and all. I suggested this to her & the perpetrators may now (years later) be out of jail - but I doubt they'll do THAT again. She put 4 flags up & just added rope between the flags... Might work for you. Mark, spam_OUTmwillisTakeThisOuTnwlink.com Peter Grey wrote: {Quote hidden}> > I wonder if anyone can help. I have an application where I wish to > photograph a boat and people at night (IR camera) but need to be able to > detect that they are there and in which direction (so I can point a camera > at them). This is to monitor offshore property. I need to get a range of > some 100 metres reliably. Hydrophones have been suggested but I am concerned > about directional capabilities and possible interferences. Does anyone have > any ideas in this field? > > TIA, > > Peter Grey > Neosystems

At 05:50 PM 17/01/99 -0800, you wrote: Mark, An interesting solution as the simple ones usually are. I do need to know the direction of the boat so I can point the camera at it. Thanks for the suggestion. Peter {Quote hidden}>Low-tech solution: Black Polypropylene rope floats on water. Let >them wrap the stuff around their propeller shafts, pulling a bend in the >rope out of a clothespin type clamp switch that turns on an alarm, and >likely they'll still be there when you get there, trying to figure what >went wrong with their prop. > > I Scuba dive, and in the search and rescue group I was in, one other >member was having problems in the Hood Canal area with some bozo playing >slalom at full speed around her basic open water class students with >their fast boat, "diver down" flags and all. I suggested this to her & >the perpetrators may now (years later) be out of jail - but I doubt >they'll do THAT again. She put 4 flags up & just added rope between the >flags... Might work for you. > > Mark, .....mwillisKILLspam@spam@nwlink.com > >Peter Grey wrote: >> >> I wonder if anyone can help. I have an application where I wish to >> photograph a boat and people at night (IR camera) but need to be able to >> detect that they are there and in which direction (so I can point a camera >> at them). This is to monitor offshore property. I need to get a range of >> some 100 metres reliably. Hydrophones have been suggested but I am concerned >> about directional capabilities and possible interferences. Does anyone have >> any ideas in this field? >> >> TIA, >> >> Peter Grey >> Neosystems > >

At 13:26 01/18/99 +1100, Peter Grey wrote: >At 05:50 PM 17/01/99 -0800, you wrote: >An interesting solution as the simple ones usually are. I do need to know >the direction of the boat so I can point the camera at it. > >>Low-tech solution: Black Polypropylene rope floats on water. Let >>them wrap the stuff around their propeller shafts, pulling a bend in the >>rope out of a clothespin type clamp switch that turns on an alarm, and >>likely they'll still be there when you get there, trying to figure what >>went wrong with their prop. >> >> Mark, mwillisKILLspamnwlink.com >> >>Peter Grey wrote: >>> >>> I wonder if anyone can help. I have an application where I wish to >>> photograph a boat and people at night (IR camera) but need to be able to >>> detect that they are there and in which direction (so I can point a camera >>> at them). This is to monitor offshore property. I need to get a range of >>> some 100 metres reliably. Hydrophones have been suggested but I am concerned >>> about directional capabilities and possible interferences. Does anyone have >>> any ideas in this field? if you can put buoys in the water, you can segment the rope, with segments small enough that you can maybe cover them with a few shots. ge