BGD Posted May 23, 2011 Share Posted May 23, 2011 On another thread here at the moment, a French Policeman is quoted with some advice to motor-homers. One tip that he suggests is to run a lead from the door courtesy light circuit (through a switch mounted somewhere easy to get to within the habitation part of the MH) to the vehicle horn. The idea is that when going to bed at night, you flick the switch to "on", and thus if any door (which has one of those push in courtesy light buttons) the vehicle horn will immediately sound, and will continue to sound constantly, until that door is closed again. At first sight, this sounds like a brilliant idea for nigh-time sleeping security - especially for those MH's without an alarm system, or where there is one of those volumetric or movement sensor alarm systems that you cannot arm whilst you are inside the MH. I wonder - has anyone done this? Is it easy to do? Link to comment Share on other sites More sharing options...
pkc Posted May 23, 2011 Share Posted May 23, 2011 Brilliant concept, I would think you would have to wire it through a relay as the load would be a little heavy for the courtesy light wiring, but it shouldn't be too difficult I imagine. One for Brambles or Clive I think. Link to comment Share on other sites More sharing options...
donna miller Posted May 23, 2011 Share Posted May 23, 2011 Courtesy light switches work by creating an earth in the circuit, and so does a properly wired horn. You should have a relay wired up for a horn because they take quite a current. My advice is that it would be easier to wire a seperate horn, using a permanent live from the leisure battery via a switch and relay, the earth feed for this could then be taken from the courtesy light in the cab, as this takes an earth from either door contact. Hey presto, someone opens the door and the horn goes off, as you say until the door is closed, or if you want to be really clevery, fit an additional relay that will keep the horn on for a set time, eg 5 seconds. Link to comment Share on other sites More sharing options...
Guest ChrisB Posted May 23, 2011 Share Posted May 23, 2011 I have discovered to my cost that horn circuits do take quite a hefty current and require some heavy-duty wiring so why not use a cheap alarm siren (readily available on Ebay for less than a fiver - just bought one to replace an external intruder alarm bell which had seized up in the box). This operates fine on the 12v circuit and with the relatively fine data-type cabling used in intruder alarm systems so should be OK on the lamp circuit. My 12v 115dB alarm is rated at 200mA. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted May 23, 2011 Share Posted May 23, 2011 BGD - 2011-05-23 2:04 PM ...Is it easy to do? Realistically, probably not. Link to comment Share on other sites More sharing options...
Guest ChrisB Posted May 23, 2011 Share Posted May 23, 2011 If cabling is going to be difficult would something like this do the job? http://cgi.ebay.co.uk/BATTERY-OPED-HOME-BURGLAR-INTRUDER-ALARM-door-window-/150557194840?pt=UK_Burglar_Alarms&hash=item230de87a58 Link to comment Share on other sites More sharing options...
Brambles Posted May 23, 2011 Share Posted May 23, 2011 Really easy. connect coil of relay across courtesy light in series with your hidden switch. Then check wiring of horn, many nowadays use a relay to switch positive, no matter, check wiring to horn and just either supply power to horn via fuse, and relay switched contacts from battery, or ground connection on horn if other is live (unlikely on modern vehicles). Other options would be if your horn works when your ignition is off, just put the relay contacts across wiring to horn switch. Link to comment Share on other sites More sharing options...
Brambles Posted May 23, 2011 Share Posted May 23, 2011 OK Derek, really (relay) easy in principle or theory. Re Ebay window alarm, you have forgotten idea here is to sound the loud car horn as soon as door is open not a feeble little thing. Link to comment Share on other sites More sharing options...
chas Posted May 23, 2011 Share Posted May 23, 2011 Only slight problem with the idea,is the scrot will probably force the door lock first by ruining it before entry. My alarm system does allow movement in the van with the alarm set on,but still allowing damage to the door locks if forced open before the alarm works. One idea I do like is the purchase of simple reverse parking sensors adapted temporary fitted to the cab doors,wired to a loud buzzer when anyone aproaches near the cab doors, they are hung from the closed windows from the outside. Link to comment Share on other sites More sharing options...
bigal Posted May 23, 2011 Share Posted May 23, 2011 Derek Uzzell - 2011-05-23 2:57 PM BGD - 2011-05-23 2:04 PM ...Is it easy to do? Realistically, probably not. My alarm system/immobilizer has four legs and eats Chappie. Probably more expensive than some of those ideas being quoted but long lasting with fringe benefits :-D B-) Link to comment Share on other sites More sharing options...
David Dwight Posted May 23, 2011 Share Posted May 23, 2011 Did this way back in the 60s when I worked in London. I had an Austin Mini in those days just bought some courtesy switches and wired them to the Horn via a hidden switch. It worked OK when I tested it never had it go off in anger as far as I know. David. Link to comment Share on other sites More sharing options...
Guest Peter James Posted May 23, 2011 Share Posted May 23, 2011 I've wired my alarm to microswitches on the door handles to trigger the alarm when the door handle is pulled. So the alarm goes off BEFORE the thief has smashed his way in. And no false alarms because the only way it can be set off is by pulling a door handle (irrespective of whether or not the door is locked, or opened) Link to comment Share on other sites More sharing options...
spartan3956 Posted May 23, 2011 Share Posted May 23, 2011 Fitted this system to a mk 1 Ford Capri in the early 70`s You could pinch them with a front door key, mine went off one night on my driveway saved my car, woke the neigbours. it cost then a pound to wire up, Good and simple idea. might fit a siren. Link to comment Share on other sites More sharing options...
BGD Posted May 23, 2011 Author Share Posted May 23, 2011 Brambles - 2011-05-23 3:55 PM Really easy. connect coil of relay across courtesy light in series with your hidden switch. Then check wiring of horn, many nowadays use a relay to switch positive, no matter, check wiring to horn and just either supply power to horn via fuse, and relay switched contacts from battery, or ground connection on horn if other is live (unlikely on modern vehicles). Other options would be if your horn works when your ignition is off, just put the relay contacts across wiring to horn switch. Excellent! Thanks for that info. I now just need somehow to dumb it down into my more basic 12 volt electrics DIY-speak............... Link to comment Share on other sites More sharing options...
Brambles Posted May 23, 2011 Share Posted May 23, 2011 deleted post. Link to comment Share on other sites More sharing options...
w1ntersun Posted May 24, 2011 Share Posted May 24, 2011 Why don,t you do what I did I bought a reversing sensor kit off ebay and fitted the sensors in the bodywork just below door level facing out. At night I switch them on. If anyone walks past they do not bleep but if anyone gets close or starts to linger the bleep increases until it is constant. This warns you before damage is done to your door and alerts you at the same time. low battery consumption as well The sensor can also be fitted just to the rear of the door facing forward ( on the conversion bodywork ) Richard Link to comment Share on other sites More sharing options...
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