Auto Shutdown Device design

[M9.9]

Hi all,
Have begun looking into what may be involved, with using mainly off-the-shelf parts to build a onboard sensor that will effectively shutdown the outboard and trolling motor after, say, 30 seconds of undetected body heat. In addition, will act as an intrusion alarm when moored.

My first thought is to begin with your standard inhome infrared sensor and build from there. Any you electronic gurus have experience with this sort of thing, sure could use your advice/opinions? Or perhaps someone may know of an existing device? I'd like to rid myself of unhooking the engine cut-off wire when going to the bow while fishing/trolling.

 

[sschefer]

Re: Auto Shutdown Device design

I get what your going for. How about one of those portable car alarms that Radio shack sells. I thought they had one with a door lock option. Just carry the fob and use the door lock relay to ground the engines ignitions. Unlock it and start the engines again. You could also take a seat sensor out of a car and use it under your boat seat and then hook that up to a really simple 30 second timer circuit with a relay. I think Sam's schematics are still around for those. Might even find one pre built at radio shack.

Edit --- I just checked Radio Shack, the don't seem to carry that auto alarm or a decent readymade timer circuit. You might find one in a brick and mortar store though.

 

[oops!]

Re: Auto Shutdown Device design

what you are essentially looking at making....is a safety lanyard.

i had some of my electrical gurus try and come up with one a few years ago......a wrist band that had a chip. and a uni directional antenna.
if the antenna did not detect the lanyard chip.....off goes the motor.
we made it ....it works.....but someone else beat us to it

we looked at body heat for the activator......but in a tinny...or on a hot day....there was no way to detect what was body heat and what was hot metal or glass.

 

[Silvertip]

Re: Auto Shutdown Device design

1) Cost to manufacture?
2) Retail product cost?
3) Is there a market?

Three basics for consideration when pondering a design for any market. Basic stuff. Items 1 and 2 are of little concern if there is no market. If it is a "dead man" or "pilot overboard" device you are considering, then there are lots of simple ways to do this. A seat occupied switch in conjunction with the standard lanyard is one. For the troller, tap into the control system. No input (steering or speed change) within a specific period and it shuts down.

 

[Splat]

Re: Auto Shutdown Device design

I too see what your doing for. I see the problems using body heat. Tho different types of radar or even sonar may be an option to look into.

What about perhaps using a lanyard, but making it passive. Such as whats used in Rf id chips. It would be totally batteryless. And woukd be.simple to remain water tight as theres no electronics working actively with no need to change batteries.

Other options would be pressure pads or sonic detectors.

The rest of the device i think would be simple enough, a PIC and a couple of lines of code and whallah.

 

[dingbat]

Re: Auto Shutdown Device design

Why reinvent the wheel? Here is what we us on my boat. Works great

http://www.boemarine.com/Autotether_Wireless_Lanyard-100-A-01/

 

[M9.9]

Re: Auto Shutdown Device design

Thanks for your ideas Guys greatly appreciated. Well, so there is at least one on the market, simple looking device, dingbat. I'm hoping to build one that is effective, simple to use and low cost. 235.00 would be alright if used for a few people on a large boat but would like a simple system for the small fishing boat or inflatable so the range only need be maybe 8-12 feet x perhaps 4 feet.

After reading the ideas you'll posted above, I began looking at what's on the market and came up with a few items all of which are motion sensor related, such as:
http://www.pestcontrols.us/motion-detectors.htm

It would seem the concern might be Sun reflection but I'm thinking the sensor will be used the opposite way. In that it will be continually triggered by human heat and motion so the sun may not be a problem. Began looking at relays as that will be the key to trigger a 12 volt high amperage solenoid (Trolling Motor pwr shutdown) and a simpler low current activated relay tripping the engine kill switch?

As for the alarm, that will be in there but is not the primary function of the unit so can look into that part of the design later. I have no plans to market it. Simply want to make it, try it, fix-it and test it until it works, then install it on the new boat just bought. Then offer the free design to others who might be interested in making one. Any and all ideas and thoughts are very-much appreciated. Thanks again!!

 

[Don S]

Re: Auto Shutdown Device design

When you can get it down to working as easily, reliably and cheaply as the $20 kill switch with a lanyard, then your idea may stand a chance. People don't want fancy, expensive safety devices they can't get fixed or bypassed if it fails in the middle of a 3 day holiday weekend.

 

[dingbat]

Re: Auto Shutdown Device design

After reading the ideas you'll posted above, I began looking at what's on the market and came up with a few items all of which are motion sensor related, such as:
http://www.pestcontrols.us/motion-detectors.htm

It would seem the concern might be Sun reflection but I'm thinking the sensor will be used the opposite way. In that it will be continually triggered by human heat and motion so the sun may not be a problem. Began looking at relays as that will be the key to trigger a 12 volt high amperage solenoid (Trolling Motor pwr shutdown) and a simpler low current activated relay tripping the engine kill switch?

As for the alarm, that will be in there but is not the primary function of the unit so can look into that part of the design later. I have no plans to market it. Simply want to make it, try it, fix-it and test it until it works, then install it on the new boat just bought. Then offer the free design to others who might be interested in making one. Any and all ideas and thoughts are very-much appreciated. Thanks again!!

I spent 10 years as Design Manager for a large sensor manufacturer. Motion and heat sensors, unless you get high quality commercial units that cost way more than the existing technology as a whole, are unreliable and are prone to false activations. You need something that is extremely reliable becouse a false deactivation in the right situation could be life threatening.

 

[M9.9]

Re: Auto Shutdown Device design

Hi all, Yes, I'd agree that parts must be reasonable in terms of overall cost. And I'm quite sure its design will include easy-bypass and pre-shut down warning through a tone through something like piezo.

I just don't see the difficulty here?, it's a simple motion detector for a wee-area in constant alarm mode (with a body on board), sending a signal that once interupted (no body on board) trips a relay connected to a 5-10 second timer/audible alarm, then another couple of relays.

One of which deactivates closed circuit or activates an open circuit to a 30 amp relay (Trl Mtr) and the other closing the kill switch (engine). I suppose the first thing is to buy the right sensor. I'd say it has to be 12 volt operation and possibly output in MAs when on and when off... I would think at the distance it would cover it would be set quite low on sensitivity.

I certainly don't see 'danger' as any factor. Boat engines stall-out when you least expect it, this, if designed and set-up correctly, will stall and stop a small motor gas and electric when you do want it to and wil pre-warn to stop a false shut-down condition.
Lol-something like that!

Edit: I suppose it could have a non-interupt circuit above a certain rpm, but that would add to parts cost. Perhaps looking at this device, it might be thought of as being used for trolling only? When operating the motor at a higher speed, your seated anyway. Actually, it might be a better idea that in order to activate the device, when you disconnect your engine kill switch tether, it's clipped-on the device which will then turn on?

 

[M9.9]

Re: Auto Shutdown Device design

Basic Schematic-1 (Have sent requests for 12V Motion Sensor output and spec info to various MFGs).

View attachment Motion Sensor Wiring.pdf