My plan has changed from using a
garden rail system to a home made dolly made from aluminium angle and skate
board wheels (see below) mounted on a 50mm x 50mm post used as a rail.
The trial plan is to use a short length of rail and a length of heavy duty sea fishing
line connected to a spindle. The spindle will be turned by a stepper motor a
friend is supplying controlled by a driver from a very handy online company
(http://www.pc-control.co.uk/) which can be
controlled via a PC and (when I have learnt Visual Basic…) programmed to
only operate in daylight hours and reverse when it reaches two data points. The
pictures will be taken initially by a webcam (I have one there already) just to
see if it is a worthwhile project. Eventually I will replace it with another
camera, probably a Canon Compact type (which can be programmed) although I am
looking into other options.
Note that the rail is on a slight incline so the cable
pulls it up gradually and then unwinds to allow it to move back gradually. I
am proposing to have the dolly moving continuously at a very slow speed
rather than starting and stopping.
The sensor may be irrelevant, since the software which comes
with the Motorbee Controller allows quite precise control of the motor
If this works I’d like to upgrade the camera to a canon digital camera with a chdk intervalometer
script, and extend the rail and cable to either 3 or possibly 5m. I think
for the garden job I can move the PC and 240v power supply to the centre
of the rail and it would be ok if the camera battery were ground mounted
in a suitable box and connected to the dolly via a long cable (to keep the
weight down). Ideally I’d like to get this done next summer.
Eventually I would like to upgrade it again to be a fully mobile system which can
take a DSLR and can be run either continuously or stop move stop. But that
is a long way off.
I have now got a stepperbee plus (which allows a pretty hefty stepper motor to be
used) with Colin’s assistance (and one of his motors) I can test how well
it works shortly and see what sort of weight it can bear. The battery I am
currently using on the static Meadowcam is 6.25kg. I should imagine with a box,
camera and solar panel it would weigh up to 10kg!
Another thing to consider, suggested by Phil, was the position of the camera and the
rail in relation to the sun, to avoid shadows affecting it.
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