MOB alarm

If you look at the DL model it only alarm's and does not have the engine cut out.

It is also cheaper even if you add in 2 extra tags
 
[ QUOTE ]
Fascinated, briefly how does it work?

[/ QUOTE ]

Not the same manufacturer but same pricipals should apply:

Raymarine LifeTag Wireless Man Overboard (MOB) System (http://rbi.ims.ca/4930-509).Using ZigBee wireless technology, the LifeTag system detects and sounds an alarm if a crew member falls overboard or moves beyond 30 ft of the boat. The Wireless MOB Pendant operates a year or more on a single CR2 3V lithium battery (over 200 operational hours). Using Ember's EM250 ZigBee System-on-a-Chip (SoC), Raymarine engineers built the ZigBee-based product in less than 50 days. The SoC combines a 2.4-GHz IEEE 802.15.4 compliant radio transceiver with an industry-proven 16-bit microprocessor to simplify the design-in process. For more information on Ember's EM250 ZigBee System-on-a-Chip (SoC), go to http://rbi.ims.ca/4930-510.

After finding this and seeing it took less than 50 hours to develop the prototype, with chips possibly costing £5 or less, and even adding another £10 each for say 3 transmitters, and a generous £5 each for three plastic cases - does it not make you wonder why it costs £00's to buy...........

Cheers
JOHN
 
Thanks for that, I get the drift now. Most of it went strait over my thick Welsh head.

I gather one isn,t tethered manually but electronically and when the electronic tether is severed one sets off lot,s of bleeping and flashing lights.
Learnt something today.Thanks again. "Dosy Mobo Celt is educated by English Raggie" /forums/images/graemlins/smile.gif
 
Anybody and views on this ? They were on Dragon's Den last week... IIRC, it was about 5-600 quid /forums/images/graemlins/confused.gif.... quite a bit more than some of the others.
 
[ QUOTE ]
Anybody and views on this ? They were on Dragon's Den last week... IIRC, it was about 5-600 quid /forums/images/graemlins/confused.gif.... quite a bit more than some of the others.

[/ QUOTE ]
I've discussed this a bit on another board.

I think the idea is unworkable. The range is too low, and there is too much chance of interference, for it to be reliable enough for an MOB sensor.

The worst problem is that it isn't "fail safe" - if the unit fails you don't get an alarm. The better systems are the opposite - they sound an alarm if they lose contact with the tag
 
The unit showen on Dragon's Den is not fail safe as it send a signal when you fall overboard, but the one I indicated it think used constant comms to keep the unit from setting off the alarm and thus alarms when signal is lost, thus fail safe.

I have been thinking about this for some time considering the use of blue tooth signal loss to setoff an alarm but have not found any info to allow me to write some software to read loss of blue tooth signal from BT dongle pluged into my nav PC

Any one any info
 
Exactly - which is why I think the whole this is doomed to failure.

I think that Bluetooth is a great idea. These days many of us carry a bluetooth device, or if not there are plenty available for a few pounds so this could be done with no significant cost per crew-member. Just register the device when they come aboard and that's it.
 
MOB alarm using Bluetooth

Bluetooth would be a nice technology to use, although personally, everyone who sails with us usually turn off their phones and secure them below to prevent loss, or water/impact damage.

The system on Dragon's Den did look fundamentally flawed for a number of reasons: as has already been mentioned here, it isn't fail-safe, and on the show, the MD of the company (clearly under pressure) claimed it had a range of something ridiculous like 5 metres. That wouldn't help if your tag didn't get wet immediately, or waited a few seconds before transmitting, nor does its "Track-Back" feature seem to take account of tidal effect upon the body in the water.

It seems the only thing it has going for it is Sonar, presumably removing the need for a radio transmitter. I would have thought this would drive the cost down rather than up.
 
There are a few Dot Net SDK's for Bluetooth available such as Franson and more info at Programming Serial Ports etc...

Depends how good your development skills are, doesn't look very complex to dev the software, probably more complex to create a waterproof self powered bluetooth device - or make all the crew keep their 'phones on and sacrifice them (the 'phones not the crew!) if they go MOB /forums/images/graemlins/grin.gif
 
[ QUOTE ]

Depends how good your development skills are, doesn't look very complex to dev the software, probably more complex to create a waterproof self powered bluetooth device - or make all the crew keep their 'phones on and sacrifice them (the 'phones not the crew!) if they go MOB /forums/images/graemlins/grin.gif

[/ QUOTE ]
I would willingly sacrifice my phone if it meant I were recovered from a MOB /forums/images/graemlins/cool.gif

But I do have a little handsfree headset for my phone that is a bluetooth device - it cost <£20 and should be fine if kept in an inside pocket.

The beauty of this way is that the tag device doesn't have to be waterproof - if it stops working then that would trigger the alarm too.
 
Hadn't thought about the cheap headsets - I've got a spare on my desk her and I'll have a look at interrogating it and checking its in range / contactable to see if its feasible.

Putting one in a sealed poly bag in your oilies pocket may be a simple way forward - would need a desktop PC to do the control but as a lot of people already have a laptop aboard this could be a way to go.

Looks like I need a bit of time to play with some code....
 
I have built a system for my boat which works on 433Mhz. I have a 5 channel transmitter which is connected to the auto pilot so that I can steer the boat from any position. Great when sailing alone. I have 6 single channel transmitters as well, connected via an RX unit to the MOB button on the chartplotter. (no need to rush to the Chartplotter.)Each crew member gets one.
Whole system cost me about £150.00 which includes the waterproof housings for the TX and RX units. I am in the process of doing a "break link "system at the moment. I designed a vehicle anti-hijack system based on the idea a few years back.
 
Yes I made a simular remote control unit using standard gate/door remote units we have available in RSA which I think uses the same frequency as yours.

My one has 12 channels to control steering, engine/gearbox control, bow thruster, windlass and my search.spot light.

The bigest problem is making the unit water proof
 
Re: MOB alarm using Bluetooth

nor does its "Track-Back" feature seem to take account of tidal effect upon the body in the water.
__________________________________________________

Neither does pressing MOB on any GPS device.

But its still better than nothing at all surely!

The emphasis on the Dragon's Den presentation, was that it alerted anyone else on board to the fact. As an extra feature, shouldn't be too difficult to link to EPIRB/DSC VHF, especially useful for single handed sailors.

Never understood why something can't be developed on similar lines to a 'kill cord', rather than an electronic/radio signal, perhaps integral with harness/Gibb strops. Any experts able to comment?
Re Bluetooth, what is range immersed in seawater?
 
Re: MOB alarm using Bluetooth

The other thing about the Dragons Den device. Another hole in the hull, which most people are resistant too, and very little evidence it would work in rough seas where it would be of most need.
 
[ QUOTE ]
Yes I made a simular remote control unit using standard gate/door remote units we have available in RSA which I think uses the same frequency as yours.

My one has 12 channels to control steering, engine/gearbox control, bow thruster, windlass and my search.spot light.

The bigest problem is making the unit water proof

[/ QUOTE ]

Got to make sure you press the right one at the right moment. /forums/images/graemlins/grin.gif
Is yours made by Bartronics?
 
You must log in or register to reply here.

Other threads that may be of interest

P
Essential pre purchase or even pre survey checks
2
Replies
28
Views
869
Refueler
Refueler

Share this page

Top