Sometimes I see a sailing gadget where I think, ‘hey, that's nice’. That was also the start of this project
. I came about a few videos of sailors who had mounted a camera
in the mast
. For example this video
or this one
. I also read on Panbo
about the possibilities of connecting a third party camera
to a Raymarine
plotter. I have a Raymarine
e7 plotter at the chart table and it does have connections for an analog or IP camera. It seemed like a nice experiment
to me to mount an IP camera in the mast
and connect it to the plotter.
First of all I consulted the manual which type of IP camera would be suitable. Because it was more of an experiment
than something serious, it had to be a cheap
camera from Ali. The Raymarine cameras are undoubtedly good but also quite expensive. Fortunately, the manual describes exactly what you need:
Unfortunately, the e7 plotter can handle 720p resolution only. I found a camera on Ali that that meets the requirements: The “Onvif IP Camera HD 720P/960P Bullet Outdoor Camera Nightvision Motion Detection XMEYE Cloud Remote Access CCTV home Surveillance
” (sight). This cam is supposed to be waterproof, but I actually don't have a lot of confidence about that, having become wiser through experience. Anyway, for about $15 you should not expect too much of course and I resealed the camera as best as I could. As usual, the software
to be used with the cam is terrible, but I managed to set the resolution to 720p and the IP address to dynamic because the plotter acts as a DHCP server. And sure enough, when connected to the plotter, I got a picture. So far so good.
One of the biggest dilemmas with a cam in the mast is of course the question what the camera should be looking at. Straight down is nice of course, but how often do you want to look at your own boat
on your plotter screen
? Forward looking might be useful, a kind of modern quay's nest. That may sometimes be practical, but usually there is not much else to see there but water
. The compromise then, a view of the bow and the water
just in front of the boat
? But who looks at the plotter screen
when something is happening right in front of the bow? My conclusion was that I really didn't want to choose and that all mentioned views should be possible. In other words, I wanted to be able to rotate the camera through a vertical angle of 90 degrees. Sure, you can buy nice PTZ (pan-tilt-zoom) cameras, but they are pricey and after all I already had a working cam. So I needed a DIY
First I bought a worm gear motor
drive on Ali. That is in itself not so easy. There are many dozens of varieties for these motors. I searched for a slow moving drive, 12V powered, with a solid long threaded shaft and preferably watertight. The latter requirement turned out to be too big a hurdle and also made it far too expensive. So no waterproof motor
then, a waterproof housing had to do the job. The motor I chose was the 12V/6rpm version of the “M6 Threaded Long Shaft Electric DC Worm Geared Motor 6V 12V 24V 6-150RPM High Torque In DC Motors Self Lock Adjustable Speed”
(sight again). It comes with a nice separate speed control board.
For the housing I used a waterproof cable junction box with 3 cable glands. Of course that is a rather clumsy and not very attractive packaging, but once at the top of the mast you can see surprisingly little of it from deck
level. Certainly good enough for this experiment.
For the data connection between the plotter and the camera a cat5e UTP cable is needed. An ordinary UTP cable as you would typically use at home will not do because it has solid cores. These could break easily due to the movements of the boat. Therefore the cable should have flexible and preferably also shielded cores, so a cable of the ‘Shielded Twisted Pairs’ (STP) type. The shielding is not necessary per se, but provides some extra mechanical strength.
In addition to the data connection to the camera, two extra pairs of wires to the top of the mast are required: one pair for the 12V power supply of the camera itself and the other pair for the motor drive. However, I didn't feel like pulling a whole bunch of wires through the boat and the mast. But technology comes to the rescue
. For 100Mb data traffic (sufficient for 720p video), only two twisted wire pairs are used for the data stream. That leaves two spare pairs of wires, just enough for the cam and motor power. But would this work
with 12V? PoE also uses these same wire pairs, but at 48V. And here I needed two separate power supplies and not one as PoE does. A test set-up at home showed that, despite the long thin wires, the cam and the motor worked just fine. So a kind of PoE, but different. Only one cable needed through the mast!
I used two toggle switches. A simple DPST on-off switch for powering the whole setup (speed control board, motor and camera) and one DPDT (on)-off-(on) switch which enables the camera up and down rotation. The latter replaces the (locking) rocker switch supplied by Ali.
Just a side note: if the indication of a switch has on or off between brackets, it means: you have to keep this position pressed and it does not lock. The indication of a classic doorbell would be 'off - (on)'. My motion switch (on)-off-(on) is therefore locking in the middle off position. When I lift the switch, the camera moves up, by pressing down the cam turns down. Because you don't want the camera to keep moving unintentionally, the switch does not lock in both 'on' positions.
With some creative cable work
and some pieces of heat shrink tubing, the two pairs of wires for the cam and the motor were extracted from the network cable. All cam and motor connections were made within the junction box. I additionally protected the network cable at the top and bottom of the mast with some pieces of heat shrink tubing.
The worm gear
motor is attached to the cover of the junction box with small bolts. I enclosed the shaft with a rubber ring under light tension and some silicone grease to ensure the watertightness as good as possible. However, my expectations for the life span of both the camera and the motor aren’t very high anyway. We’ll have to see about that.
The nice thing about the motor controller is that you can set the speed. The maximum rotational speed of 6rpm is still much too fast. I adjusted it in such a way that the motor turns as slow as possible but still keeps moving when it turns the cam against gravity. This makes that it takes about 6 seconds to rotate the full angle of 90 degrees, which is perfect for reasonably accurate positioning.
For the two switches I made a simple panel of a piece of aluminum
plate. This does look a bit out of place in my switch panel, but that can be upgraded easily in a later stage.
I bolted the junction box with the cam to the masthead fittings. This way he has a fairly clear view and is not in the way of anything.
And yes, it works. The image on the plotter is quite good despite the quite moderate resolution.
And although I don’t recommend using it for navigation
, it is nice to have a forward view when I’m solo sailing and need to do something below deck. At daylight that is, the IR lighting
is of no use at night in this setup of course. For a few bucks I learned a lot and had fun putting it all together. And at least I can now easily inspect my wind
instrument, Windex and VHF