Color Backup Monitor

Probably the most annoying feature of our 2000 Foretravel was the backup camera system.  This consisted of a black and white camera mounted inside the upper rear portion of the motorhome looking out through a glass window in the air intake plate.  The monitor was a 5 inch black and white CRT mounted in the dashboard.  The monitor was also used for displaying the tank level status.

The original camera was totally hidden behind the small window in the center of the air intake plate.

In operation, the image was low contrast, not very sharp, and of a very small area.  The field of view barely covered my towed car, stopping several feet behind my rig's rear bumper, and did not extend into either adjacent lane.  I discovered how inadequate this was when I "dinged" the exhaust pipe while maneuvering back into a tight spot in my driveway.  (I thought it would clear!) :-(

I improved the performance somewhat by adjusting several settings on the monitor.  These adjustments improved the contrast and reduced the overscan of the monitor increasing the field of view about 10%.  I could now see the lower part of vehicles I was passing.

The real answer was to replace both the camera and the monitor.  I chose to use a color LCD monitor and a quality color camera.  One of the problems I had finding a suitable monitor was that it had to have a function which reverses the picture left to right, to provide an image which matches a rear view mirror.  With a simple backup camera setup, this reversal can be done either in the camera or the monitor.  In this case, the tank gauge electronic unit outputs the information in reverse format, so the monitor had to be the reverser. 


I found a new LCD color monitor on eBay which met all my requirements for under $125.  I decided that I would mount the new monitor in front of the dash panel on an adjustable mount.  I mounted a flat plate on the rear of the panel where the original monitor had been.  To this I mounted the swivel mount which came with the new monitor.  This allows me to aim the monitor directly toward me for best visibility.  Initially I used this setup with the old camera.  It worked fine with the black and white camera, and even increased the field of view a slight additional amount.

The new LCD monitor is mounted external to the dash panel.  This image is of the rear of our RV garage.

One technical problem was a spec stating the voltage input to the monitor was 12 volts maximum.  As the vehicle electrical system can reach as high as 14 1/2 volts (plus spikes), I needed a voltage regulator.  I was going to build one when I discovered one already mounted on the old CRT monitor.  I pulled it out and used it as-is.

The next step was to replace the camera.


Another search of eBay turned up several dealers who carried a large variety of color cameras.  I initially selected one with a stated field of view of 90 degrees.  When it arrived I found the field of view was much less.  I called the vendor who apologized and stated that the CCD in that unit had just been changed from a 1/3 inch to a 1/4 inch by the manufacturer, with no change in the lens.  He suggested a submersible unit with a Sony 1/3 inch HAD CCD.  This is a very high resolution unit which also has a bank of infrared LED's for vision in total darkness.  He felt so badly about his inadvertent misrepresentation, he sent me this camera as an even exchange for the first one even thought it carried a price tag of almost 60 dollars more!

The camera is very well made, it is completely weatherproof, and produces an excellent image.  The fact that it also works in total darkness is an added benefit.  I initially made a simple bracket that clamped to the outside of the air intake grill, covering the original camera window.  I had to change the connectors on the existing wiring, but did not have to add any wires.

The operation is superb!  The image is bright, sharp, and has a very good field of view.  I can see a full lane on each side.  My only complaint is that if I point the camera low enough to see the rear bumper for backup maneuvering, I cannot see the rear of my towed car.  If I point the camera to almost the horizon, I cannot see the first couple of feet behind the motorhome.  The obvious answer is to make the camera adjustable!

Adjustable Mount:

There were a couple of requirements to take into consideration in the design of the camera mount.  It obviously had to be able to aim the camera higher or lower.  It also had to move the camera to the rear when pointing downward.  The rear of the Fortravel has a bend above the engine grill which prevents the factory camera from seeing the ground immediately behind the coach.  The externally mounted camera did better, but still could not see the bumper or the ground really close to the motorhome.

I designed and built a mount using a 4-bar linkage which moves the camera to the rear as it lowers the angle.  In the up position the camera is tucked up under a protective cover.  I mounted a gear-head motor and an additional gear reduction on the inside of the air intake grill.  A linkage from the gear pushes and pulls the camera mount through the plate.  A pair of limit switches stop the motor at the upper and lower ends of travel.

The linkages are all bushed with nylon to prevent wear and to provide a certain amount of friction for stability.

The appearance of the completed camera assembly is certainly not as "smooth" as the almost invisible original camera, but for me, the increased usability far outweighs any loss in esthetics.

The camera is installed on the 4-bar linkage mount, which along with the motor drive is mounted on the air intake plate.
The finished camera installation with the camera in the travel (up) position.  The upper piece of the mount forms a watertight shield to help keep the lens plate of the camera dry.
Here the camera is in the backup maneuvering (down) position.  Note how far the camera has moved to the rear to look past the "hump" in the rear wall.
Image with the camera in the travel position.  Even though this shot is in a rest stop, you can see the amount of side and rear visibility it provides.
Image with the camera in the backup mode.  Note the rear bumper, the towbar, and the ladder at the bottom of the view.  I can see obstacles within a couple of inches of the motorhome across the entire width.

The addition of the motor driven mount did require two additonal wires to be able to control it from the driver's area.  There are several unused wires in the overhead area of our rig above the bed.  I used two of these.  I found the other end of them in a wire loom on the left side of the engine compartment.  Also in the engine compartment are a number of wires labeled as spares.  These run to under the dashboard.  This made completing the wire runs fairly easy.  A switch under the dashboard controls the camera position.

This was obviously not the typical do-it-yourself project, however if you were to omit the adjustable camera mount, there is nothing here that a "handy" owner with a slight knowledge of electronics could not do himself.

The total cost of this new system (NOT including my labor) was under $300!  Its performance has exceeded all my expectations.  It is bright, sharp, and clearly shows everything I want to see for the type of driving I am doing.

Addendum of February 2007

Over the last several years the display of the monitor has varied with the external lighting.  Sometimes it is bright and clear, and other times it is hard to get a good  image.  It was not too bad, but was annoying.  After reading several messages about people on the Foretravel Yahoo maillist replacing their monitors with a "Super 7" TV/monitor I went on Ebay and bought one.  I replaced the color monitor with this one and now see a much more consistent bright image.

I am now using the original monitor with my computer at home as a video monitor for when I do video capture and editing.

Replacing the previous monitor with the "Super 7" was easy and straight forward.  This monitor also offered a "reverse image" function.

The main effort involved opening the case and hard wiring a couple of cables to eliminate the need to have any connectors on the edge of the monitor.

The results are excellent.  I have no complaints of brightness or contrast of the resulting image.




Dick Mason, Prescott, AZ 12/10/03