Wolf's Motorhome Modifications

... and Other Stuff

A Stable Alarm System

We went to see the Statue of Liberty and had the, well, misfortune to stay at a campground that seemed to host as many homeless people as it did campers.  Oh, you could see the Statue all right.  In fact, you kept looking at it to keep your mind off the blight in every other direction.

I've been in a number of parks where the owners have long term arrangements with people who are living in their campers.  When every I pull into one of these camps it seems like I'm there on business or just overnight so we stay anyway.  We sure don't like it though!

It was obvious that a good alarm was needed.  I wanted one that would make the motorhome secure not only in the drive but also when out camping ... dogs or not.

First Attempts

My first attempts were with 12 volt car-type alarms.  The changing potentials in the motorhome seemed to make these very unreliable.

My second motorhome had an infrared eye down the middle.  Although secure, I wanted more.  I wanted to secure my equipment, batteries, etc.


All materials were purchased from Radio Shack.  The contacts are normally closed magnetic switches.  The alarm itself is a home protection alarm.  Where the battery is to go I put a piece of two-by-four and mounted a terminal block to that.   The different areas of the motorhome are then marked and wired to the terminal block.


I have a full basement with 10 hatch-type doors.  I installed magnetic contacts in each by mounting the magnet to the door and the contact to the lip of the doorway.   Having a basement makes things EASY.

Hatch Alarm Contacts (9166 bytes)These contacts are split into four groups:  Front-left, rear-left, front right and rear right.  This was done so that if a contact failed, it could be easily located and replaced.  In the last year I had one contact fail because the contact point between the reed switch and the contact screw terminal was not soldered.  It worked fine until winter when expansion caused it to loose continuity.

The front-left group has a contact for the front driver's door.

All contacts are wired to a 8 terminal junction block.  These are then wired to the "immediate" part of the alarm.  Any door opening will immediately sound the alarm.

The motorhome main entry door is wired to the "delayed" part of the alarm.

Motion Detectors

Rear infrared detector (13393 bytes)D'Berge Taking Care of Motion Detection (14895 bytes)If my dogs can't go, I normally won't.  Hence, any motion detection must be disabled for when the poochies are with us.  I'll cover that later.  Suffice it to say that my 170 pound Irish Wolfhound will take care of "motion detection" when the detectors are cut out.

Two motion detectors were installed.  One was installed in the rear bedroom and one covers the main living area.  These two detectors cover any attempt to enter through a window.  As they are infra-red, motion outside the motorhome is ignored.

The Siren and Strobe

The horn is mounted in an area that allows it to bellow it's alarm to the outside but does not allow someone to disconnect it.  It would be best if you figured the best place on your camper yourself.

I placed a strobe light in the area of the front window.  Alarms are notoriously hard to find.  Strobe lights are not.

The Guts

The guts of the alarm was mounted under one of the dinette seats.  It was wired to the batteries.  The 110 volt adapter was wired to one of the sockets through a pigtail.  Hence, the alarm works fine on AC or DC.  I use it at the campground, with the dogs inside or not, at home and when stopping along the road.

Turning It On and Off

Loosing the key to the alarm would render it useless.   Two keypads were installed.  The first enables the motion detectors.  The second activates the alarm.

Keypads to turn on infrareds and the alarm (12859 bytes)When leaving, all contacts must be working or the alarm will not set.  I normally leave the motorhome and reach in through the screen door hatch to enter the code and set the alarm.  You can also set the alarm from inside and have 12 seconds or so to leave and lock up.

When entering, you have 12 seconds to enter the code to disable the system.


The alarm is regularly tested by my wife and kids who open the door and promptly forget the easy-to-remember code.

Radio frequency interference does not bother it.  I operate 80 through 3/4 meters without falsely setting it off.

I have had a number of instances when the alarm went off and an outside door was found ajar.  It works.

Return to Motorhome Index     email.gif (5698 bytes)      Email Steve Wolf, W8IZ