Lost Models... what do we really need? - RC Groups
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Jul 05, 2005, 05:09 AM
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AnthonyRC's Avatar

Lost Models... what do we really need?


There seem to be a few 'lost model' posts on here recently. With the typical AP-equipped plane floating around with $500-$1000 of kit it's clear that an 'insurance policy' is required.

One option is the classic 'lost model alarm'. These are available everywhere, and can be built following rc-cam's recipe. They suffer from a couple of serious flaws, firstly, they are audio, and have limited range. Secondly, they are powered from the receiver, and rely on the fact that they plane crashed with batteries, BEC, Rx, and connection to the LMA intact... sadly the chances of this happening are pretty poor.

So, given a clean slate, and ignoring any technical difficulties, what do we need?. Let me take a first pass at some specifications:

- Lightweight, < 30g
- Radio Transmitter, not audio, using legal frequencies
- Low power, 3 days of emission required
- Powered from backup cell, not dependent upon main, or Rx battery
- Robust, and self-contained, even if servo connector is wrenched out, must still work.
- Supplied with small directional receiver, allowing triangulation to locate model
- Reasonable cost, < $50 on the model, < $100 on the ground
- Oh.. and ideally waterproof

Did I miss anything???. Something tells me that there would be a queue of APers lining up to buy something with these specs.
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Jul 05, 2005, 08:39 AM
Smashes Things
RCTyp's Avatar
Easily moved from model to model.

Typ
Jul 05, 2005, 08:57 AM
Registered User
I would think that a simple timer would be good for a "trigger". The tracking device would kick in after 1 hour ( I never fly for that long at one time)
The technology is available, we just need it lighter!: http://www.gundogsupply.com/tracking-collars.html
Jul 05, 2005, 08:59 AM
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AnthonyRC's Avatar
Almost forgot, another required feature: at least 1 mile range (more would be nice)
Jul 05, 2005, 09:01 AM
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Looks like our rocketry friends have a system already. The "Walston" looks like a winner! Haven't found a price yet though...
http://www.vernk.com/RocketFinding.htm
Jul 05, 2005, 09:03 AM
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Ah, ebay has everything. Looks like quite an investment, but who can put a price on this kind of insurance?
http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WDVW
Jul 05, 2005, 09:44 AM
Registered User
Check this out. http://www.theplanelocator.com To me this looks like a good affordable solution. Looking back at the equipment I've lost the price seems cheap. A search of the FCC database shows that the operating frequncy is about 220 Mhz and the company also makes tracking transmitters for law enforcement. The setup is also sold under a different site as a cat locator. Recently in our area there was a news clip on tv where a disable child walked away from home and could not be found. He had one of these transmitters on a wrist strap and the local law enforment agency gad the mating receiver. He was found in short order in an unlocked neighbors house watching tv.

I have no doubt this system would work, just got to convince the wife of the cost benefit!

Vince
Jul 05, 2005, 09:50 AM
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jschrader's Avatar
Of course there should be an audio signal as well. At least in 1st-level-loss mode (as long as the thing is connected to main batteries). When the main source is "dead" for any reasons it should switch to not-yet-hopeless mode and send a radio signal on it's own built in "nondestructible" power source. (And even then it might be possible to send a decent beep say every 30 seconds without consuming too much power).
Jul 05, 2005, 09:54 AM
...in the skies...
Cats Eyes's Avatar
I am watching this thread with keen interest. I went through the same thing last fall when Steve Nolan lost his SS in the swamp. See thread Finding a lost model. Also see my web site Finding Lost Planes. I'm still waiting for a good solution.

I am working on a lost model alarm based on a dollar-store "entry alarm." I have tested the 90dB version and it's audible to about 200 metres. (See my web site "Dollarama Special"). There are 120dB versions that should be even better. These have self-contained batteries in case plane power is cut. Unfortunately they're a tad heavy at 1 oz. You can cut away the plastic, but that appears to reduce the efficiency of the sound element.

That should cover the short range. For the long range, a radio TX would be a better solution IMO. Unfortunately all the effective ones I've seen to date need a HAM licence to operate.

Hopefully someone in this thread will come up with something.

-- Kevin
Jul 05, 2005, 09:59 AM
...in the skies...
Cats Eyes's Avatar
Quote:
Originally Posted by Vince53
.... The setup is also sold under a different site as a cat locator. ....
Meow!

Sounds like this is the one for me, then!

-- Kevin Cat
Jul 05, 2005, 10:03 AM
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AnthonyRC's Avatar
Interesting stuff!. The plane locator site is very interesting. Price of the piece in the plane is good ($39), but the receiver cost is a little high ($199).

One thing that does seem to be missing from this system though is a connection to the R/C Receiver to allow it be be powered up only when the Tx signal is lost. Without it, the plane is radiating this RF signal at all times. Finding a lost plane near a flying site with 20 other models, all radiating while flying around, might be fun (even though they might well be on different channels).
Jul 05, 2005, 10:12 AM
Registered User
Quote:
Originally Posted by AnthonyRC
Interesting stuff!. The plane locator site is very interesting. Price of the piece in the plane is good ($39), but the receiver cost is a little high ($199).

One thing that does seem to be missing from this system though is a connection to the R/C Receiver to allow it be be powered up only when the Tx signal is lost. Without it, the plane is radiating this RF signal at all times. Finding a lost plane near a flying site with 20 other models, all radiating while flying around, might be fun (even though they might well be on different channels).
I'd vote for a reset button on the TX that starts the signal 1 hour after resetting. Just hit the button when you change batteries. If you don't reset, the TX starts up after an hour.
Jul 05, 2005, 10:20 AM
Registered User
I wonder why you couldn't just buy the lost model transmitter and use a programmable scanner with a directional antenna to receive?
Jul 05, 2005, 10:26 AM
Registered User
As with most "Problems" someone else has had the same (or simlilar) and already found the answer.

How about this for a novel approach ?

Falconary

A bit pricy, but then, what price peace of mind ? (I sound like a salesman )

Seriously, worth a look.

Paul
Jul 05, 2005, 10:50 AM
Registered User
AnthonyRC's Avatar
These falconry systems are far too expensive for this application, at least in my mind... another 100 quid ($175) on the plane is just going to increase the pain in the case of a complete loss (like dropping the poor thing into a lake or the sea).


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