Detector Arm Rotation Base

Ok,

Yesterday, I worked on the rotation base for the coil detector arm.  I had to add some counter balancing weights to the arm to offset the weight of the PVC and coil assembly.  I ended up using 1" PVC.  It fit well into the aluminum round tubing of the arm, but it has quite a bit of deflection.  I may try wood to see if its any better.  The 6" lazy susan bearing I used is rated for 500lbs, but that is all with the weight centered on the bearing.  Weight isn't something normally desired, but in this case the bearing will last much longer, and the overall weight addition, is still well within what the rover can handle. As a footnote, the arm rotation base is smooth as silk.  My off the cuff testing looks like the whole arm assembly can be moved with a pound or so of force.  This will be good when adding the motor.  I still have yet to redo the 2" square tubing on the arm.  I got the material, but didn't have time to work on it.  That and adding the motor/gear assembly should finish up the arm.

One of the next items on my to-do list is to bridge the two enclosures.  I don't like any connector solution I've able to come up with, so I will join the two boxes together in the center and cut out an access port between the two, I will seal the edges with insulating seal tape to prevent water from leaking in through the gap.  This will mean the only penetrations I will need into the box will be 4 water tight cable glands for the wheels, 1 for the arm, and one for power from the generator.  I can add more later if I need to but that looks  to be it, and cable gland strain reliefs are cheap.  Way cheaper than connectors.  With the frame, and hard wiring i will be using, it doesn't appear that this rover will be capable of easy disassembly.  Once I get all that done, I can mount the parts for the Control Box, and start wiring.

For the non-driven wheels for position feedback, I also figured out how to that as well.  I will be using some inexpensive bearings from a set of wheelbarrow wheels I picked up for about $4 each on sale.  Using that, the wheel, coupled to an encoder with a 5/8" all thread shaft should work well.  I didn't have time to work on that, other than a rough assembly, but it looks like it will work.  I actually considered using this design for the arm rotation base, but the height was a bit much. If the lazy susan bearing doesn't work out, I may use this on the arm as well.

Below are some pictures of the base and arm.