Emergency locater

[jimdavis]

Good day all
I am looking for a design, or a product that would release a bobber, on a string that would locate the sub if it looses power or another problem. For the string , I am an ex electrican and we used a product called Jet Line that you shot through a conduit and it feeds string from the center. so that problem is solved its just the release design I am haveing problems designing. Any thoughts? I did see a timer on a serch of the site but the last post was in 2009. or is this something not needed. In a pool it woUld be easy to see your boat , but a pond would be different.
Thanks
Jim

[PaulC]

Re: Emergency locater

Don't know if this would interest you or not but I recall a fellow who would secure the bobber with a Tic-Tac mint. If the boat went down, over time the mint would dissolve in water and the bobber would be released and rise to the surface.

[jure george]

Re: Emergency locater

Hello

What if the operator forgets about the breath mint and runs his sub all day, the mint dissolves, the bobber is released and fouls the prop and possibly kills the esc. The sub is dead out in the water. There has to be a small circuit to release the bobber if there is power failure Or loss of signal?? Something DIY ??

George

[PaulC]

Re: Emergency locater

Hey, I'm not saying it was foolproof.

[Guest]

Re: Emergency locater

Some people covered the mint in grease- slows down the dissolve.

Here in the UK, pingers are more popular. This is a self contained noise making gadget that emitts a swooping sound, quite distinctive. In the event of loss you use a hydrophone to locate your pride and joy using sound.

It does mean constructing a hydrophone. Pingers were also DIY, although you can use a modified aeroplane lost alarm.

[KevinMC]

Re: Emergency locater

With a little modification you could use a standard "missing pulse detector" failsafe device to trigger a release. Of course the circuit would have to be self-powered or backed-up for long enough to still be able to power the servo and release the buoy after x seconds of loss if signal and/or total system electrical failure. It's certainly not the simplest of solutions, but it is one way to solve it. I can elabourate if this sounds like something you want to try.

[jimdavis]

Re: Emergency locater

You know I may have solved my problem, I have a relay to turn on running lights, and it has a set of no and nc contacts, no if I used the nc contacts in a failer it would drop power to the coil and deploy the bobber. now the problem is my lights would be on all the time. or I can get another relay and do the some thing. There has to be a simpler way.

[ramius-ii]

Re: Emergency locater

Hi Jim,
I think you have the correct idea and for me I used a small electromagnet which holds down a balsa wood cylinder painted safety orange. The top of the cylinder has a hatch cover glued to it and the bottom of the cylinder has a tin disk from a tin can. The cylinder fits between the outer hull and the wtc. The fishing line was wound onto a plastic sewing machine bobbin. When you loose power the cylinder will deploy. If you wish to stay with "all plastic" then you may consider using an old pill bottle from a pharmacy. I went a little overboard and stuck a flashing led and battery in my cylinder with a plastic pin which keeps the led on switch (home made) open until the cylinder is released.

Best, Ed

[jimdavis]

Re: Emergency locater

Ed
Thanks for your advice, I have not considered a light, and I like that, I wonder if a small strobe would work.....Now its getting fancy.
Thanks
Jim

[ramius-ii]

Re: Emergency locater

Hi Jim,
You are very welcome! Yes, a strobe might work and it depends on the size. Red flashing led's are common so no additional "electronics" would be necessary. You can use watch batteries to power the led.

Best, Ed

[scott t]

Re: Emergency locater

Put a mercury switch from a thermostat that when released the bobber rotates and
closes the switch to energizes the flashing lights and why not a siren sound.

Scott T

[zotfidjy]

Re: Emergency locater

Hi, here http://www.miniflotte.net/pages/a_techs.htm have a very simple solution, one spaghetti.
Take a look there, he also make a comparision table for somo brand of spaghetti.

[ramius-ii]

Re: Emergency locater

Hey Jim!
If you are still working on your locator then here is something that you may find useful? Most people us a magnetic reed switch that look much like a glass fuse. A company by the name of "Magnasphere" (www.digikey.com it would be part number 735-1007-ND. Thus with a small electromagnet to hold your locator in place when you lose power the electromagnet will lose it's hold and the locator will float to the surface! The switch, mounted in the bottom of the locator, when released can trigger anything you wish. As for a plastic cylinder, one size that may be perfect is the long cover cap from an old bottle of modelers super glue.

Best, Ed

[robert f.]

Re: Emergency locater

I must say the option of pinger and hydrophone(s) is very appealing to me. No release mechanisms, no wires that could be caught in something...

Andy, where could I find the build schemes (if that's the correct term) for these items?

Best regards,

Robert

[Guest]

Re: Emergency locater

The pinger chips are made available to AMS members only, they cost £5 each I believe. If you can code a microcontroller (PIC, Atmel), you can come up with something similar, the design emitts a swooping sound somewhat like an ascending square or triangle waveform, which sounds every few seconds. As time goes on the interval between swoops increases in order to preserve the life of the battery. The pinger can apparently last for several days, which gives you a sporting chance of arranging for a diver if the model goes too deep to swim for it yourself. Details on how to build the hydrophone amplifier are published on their forum, it also shows a built up pinger which uses a PIC microcontroller coupled to a piezo mounted in a small capsule (plumbing fittings) with a self contained power supply- two button cells.

http://www.theassociationofmodelsubmari ... ydrophones

The piezo transducer is epoxied into the enclosure, which also acts as a resonant chamber. The unit can be mounted inside or outside the main dive module. For small models, mounting externally could really upset the balance and internal mounting will take up too much space. Alternatives could be using an endcap on a dive module and modifying it to create a small watertight area of its own.

The original link on how to build hydrophones seems to be dead, but here is another that should work well enough-

http://maaheli.ee/main/archives/272