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How long a time-out for a deadman timer

R/C Submarine modelers

How long a Maximum timout for a Deadman timer?

1 hour
7
41%
2 hours
5
29%
3 hours
2
12%
4 hours
2
12%
6 hours
0
No votes
Longer than 6 hours?
1
6%
 
Total votes : 17

How long a time-out for a deadman timer

Postby RickNelson » Thu Aug 27, 2009 4:03 pm

Hi Al,

Thanks for your comments. So far the poll shows 6 people willing to go with the modified DT. We need four more to sign up and we can put in our orders. $30 + $5 shipping. The contact info is on the "Shipping/Terms" page of that web site in the previous post.

Ken suggested we keep the 10 second countdown as a selftest prior to launch. Will have to come up with some way to view the LED. Maybe a fiber light pipe.

Still need to get an idea of what folks would like for a maximum time-out. I put some suggestions in the poll but if someone has other ideas let me know.
Rick Nelson

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fail safe system

Postby Mike Dory » Thu Aug 27, 2009 4:56 pm

Howdy - Before I start let me say there nodisrespect intended of anyone. But is something wrong with the current Sub Safe systems that Sub-Tec as sold for years? Just why do we need to do something else? Best Wishes... Mike Dory
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Re: fail safe system

Postby petn7 » Thu Aug 27, 2009 5:17 pm

Mike Dory wrote:Howdy - Before I start let me say there nodisrespect intended of anyone. But is something wrong with the current Sub Safe systems that Sub-Tec as sold for years? Just why do we need to do something else? Best Wishes... Mike Dory


My understanding is that current failsafes kick in pretty quickly (5-10 seconds) due to loss of Tx signal. What RickNelson is offering/suggesting is something that kicks in after a long period of time (1+ hours) no matter what, unless there is a manual disengagement of the deadman timer.
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Postby Al Nuci » Thu Aug 27, 2009 6:32 pm

To further elaborate on Mike's question, and please don't take this wrong Mike, but while the sub safe units are without question a necessary piece of equipment, they too are subject to failure and when all is said and done you want all the safety options one can muster to retrieve your boat. Whether your model costs a few hundred dollars or thousands you want to know where to look for it. I've read to often cases where a submerged boat will get caught on something or stuck in the lake bottom, or even skirt along the bottom to the other side of the pond. I feel If you had an area specific to look as that marked by the buoy, that in itself would be worth it's weight in gold and hopefully help avoid getting overly upset, IMHO. However, I don't know that I would want to pitch a tent and set-up camp awaiting extended time for the emergency buoy to deploy. :)
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Postby RickNelson » Thu Aug 27, 2009 7:16 pm

Mike,

What Al and petn7 have said is pretty much what I have wanted to add to my subs. A "simple" device that will reliably run on it's own power and produce some kind of activity at the end of a long (hours) delay. I envision as Al and Petn7 have said releasing an emergency buoy(s) that's tethered securely to the sub and can be used as a location device for a sub sunk. Just like we did on the 1:1 boats.

This Deadman timer would NOT replace the Failsafes that are available but would try to cover the problem of a sub stuck on the bottom for some reason and an emergency blow initiated by a Failsafe would not release it. Most likely the failsafe will have initiated a blow already before the Deadman Timer released it's buoy.

I had originally pursued a mechanical clock type of mechanism. I even located such a device but they were priced at $225!

I used to fly free-flights as a kid and remembered the DTs we used when we wanted the bird to descend for recovery. The early ones were nothing more than a fuse or wick that would slowly burn down to the point were it would burn through the holding string to release the horizontal stabilize.

I feel that the modified DT device Ken Bauer is offering is a good KISS solution. If one didn't want to activate a servo a relay switch type device could be activated instead. This could energize a solenoid or something. However, now the Deadman system is dependent on a power source to electrically activate something. I like the servo idea. I plan on waterproofing a servo which will withdraw holding pins on the emergency buoys. I plan on two buoys in case one of the buoys is blocked. A reel of fishing line could be the tether.

I hope I have satisfactorly explained my intent.
Rick Nelson

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RE: Fail Safe Systems

Postby Mike Dory » Fri Aug 28, 2009 3:12 am

O.K. I think I see where you are going with this. I'm not sure but did you know you can change the time needed on Sub-Tec fail safe system just by changing the value of one of the resisters. I've had several boats with two fail safe units in the past. one empted the ballast tank (that was set at 7 seconds) and the other dropped a 3 Lbs. brass keel and was set to activate in 20 min. both went into timer mode with the loss of radio signal.

Bud Lederer, one of the great early R/C Sub drivers, has a fishing bobber that releases from a second fail safe unit after 15 min. His boat, a 1/32 scale Gato class (that right at 10 Ft. long) had lots of room for an additional safety system. As I recall, Bud had a spring loaded hatch that was held in place with a 1/16 inch. brass pin. when the fail safe unit engaged a servo just pulled out the the brass pin. and the bobber was released to the surface, attached with to 50 ft. of fishing line. It worked very well. Your so right, It's always a good idea to have a plan "B" When your boat is on the bottom. It's a mighty empty feeling to go home with only your boat stand..... Best Wishes to all .....Mike Dory
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Failsafe

Postby T. Schulte » Sat Aug 29, 2009 12:11 am

Hi all, been using Skip's failsafe in my typeVII for almost 10 yrs now and my own prefference 7 seconds is plenty long time when you don't where your sub is. Just curious, do any of the failsafes work in the event of a catostrophic flooding? If the reciever and failsafe's gotten wet in the WTC then what? Food for thought,Ted Schulte SC#0611
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Postby hakkikt » Sat Aug 29, 2009 3:11 am

That deadman timer on top of the normal failsafe system looks very useful to me. If you put it into its own small WTC with its own power supply, the boat can flood & sink all it wants.

There are other ideas, like wedging in a buoy with a lump of sugar, but this DT thing is elegant and flexible. Creative people can probably think of all kinds of things it could do, preparing for all kinds of disasters - exploded WTC (from gassing battery... it happens!), boat sticking belly-up in the mud... whatever.
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Postby Ramius-II » Sat Aug 29, 2009 12:34 pm

Hi All!
Thought it might be okay to join in the discussion. I think we all have given extensive thought to ways to prevent the loss of our boats and being able to find it when necessary. Aside from the lost signal failsafe I incorporated a simple water detector that has strips of narrow copper tape and the very bottom of the WTC. In addition there is also a buoy that is held in place by a disk shaped electromagnet. As long as the sub has power the buoy is held in place. The buoy on the outside looks like one of the hatches. Just for "fun" the center of the top of the buoy has a flashing red LED.
[img]
Image



Image



Image

Hope this benefits someone.

Best, Ed[/img]
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Postby Robert F. » Sat Aug 29, 2009 4:14 pm

Good suggestion. Ed!

But this device is to be activated by water getting into the WTC, while the deadman device is to act as an independent timer. So it would also work (after some time) in case the boat would be stuck in weeds or whatever, but with its WTC stiil perfectly dry.

Ideally, I would like to hook your device up to the deadman timer with both the timer and the electromagnet being fed by the same power source, which would make it fully self-supporting. Wold this be feasible, Rick?

Robert
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Postby Ramius-II » Sat Aug 29, 2009 5:38 pm

Hi Rick!
Actually the buoy is an automatic "deadman device". As long as you have more than half of your battery power the buoy will not deploy as it takes a very small amount of battery current to keep the electromagnet holding the buoy in place. The flashing LED serves as beacon in case you did not allow enough fishing line for the buoy to completely reach the surface!

The WTC water detector is just another safety device should you start to take on water. You connected it to the same place as your lost signal device to blow balast so your sub will rise to the surface. Hopefully before it is too heavy with water to surface. The connections marked "To LED" would connect to what is called an "Optical Coupler" which is a package containing an LED with a transistor. When the LED lights, the transistor side of the opto is like a solid state switch that has no effect on the lost signal devices output so either device will blow balast. Simply put, loose radio signal, surface the sub. Start taking on water, surface the sub. You can also add a light if you have water so you know if the sub surfaced because of water or lost signal.

Best, Ed
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Postby RickNelson » Sat Aug 29, 2009 7:23 pm

Hello All,

Great discussions here. Ed, the only thing that I don't like about the electromagnet approach, and I had considered it before, is it is an additional load on the battery which I do not want to impose.

The DT is an "If all else fails" totaly independent approach to trying to find a boat on the bottom that has not responded to anything else for one reason or another.

I do plan on putting the DT in it's own WTC along with it's own battery. I plan on either keeping the servo in the DT WTC or possibly extending the servo leads outside of the WTC to a waterproofed servo. Haven't decide which yet though the former approach seems better. I also want to make sure that whatever system I implement it does NOT put a load on the DT battery until Timeout. I want to preserve the battery charge as much as possible. I would consider loading the battery at Timeout, which should be almost never and at that point who cares about the battery condition as long as it will support the Timeout event.

Robert, I see no problem with your approach other than the possible drain on the battery due to the electromagnet depending on how you implement it; always ON until DT Timeout (battery drain) or always OFF until DT Timeout.
Rick Nelson

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Postby Robert F. » Sat Aug 29, 2009 7:36 pm

Well Rick,

I'm thinking about keeping the electromagnet OFF until DT Timeout (so no battery drain). At DT timeout, the electromagnet is activated, pulling a release pin from the buoy. The buoy could be additionally equipped with a LED and a small battery (called a "button cell"?) to power the former, depending on the size of the buoy.

Robert
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Postby RickNelson » Sat Aug 29, 2009 7:43 pm

I just received this email from Ken Bauer (Mr. DT) explaning the servo operation from power on through DT and beyond:

Rick,

The servo operation is simple and would work for you as is. There are only two servo positions, the normal initial position and the DT or release position. A couple seconds after the DT the servo moves back to normal position and will not go to DT position again until another full cycle timeout. You can restart the timer as many times as you want either by pressing the button or powering it up, but the servo will just stay in the initial position. The timer sends a command to the servo to go to the first position with each power up, but if it is already there it won't move.

I would suggest a time increment of either 5 or 10 minutes for your application. The timer can count up to 40 increments, so this would give either 200 or 400 minutes max time.

-Ken


This sounds like it will fit our needs just right. Any comments?
Rick Nelson

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Postby RickNelson » Sat Aug 29, 2009 7:46 pm

Robert,

That sounds likea realy good approach. The DT will have no problem supporting that.

Rick
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