Ross' H015 Build

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Ok, now for the drive system upgrade.


  Wiring_H015.pdf (Size: 225.37 KB / Downloads: 10)

Here is the system wire diagram for the drive system.  It's just a more detailed version of the existing diagram but with a DPDT switch and charge port added.  The LED system is run from a separate arduino nano and powered from the 12V to 5V step-down board.


Motor Controller: https://www.amazon.com/gp/product/B00XZ9...UTF8&psc=1

RC Controller: https://www.amazon.com/gp/product/B01BXS...UTF8&psc=1

DC-DC Step Down Converter: https://www.amazon.com/Lysignal-LM2596-S...rter+board

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This is the arduino code I used for the drive system. It's basically the code available here but minus the LED stuff.

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I designed the drive platform to fit inside the LEGO greeblies. Since the body of the droid is pretty light, it's made from 1/4 plywood and the corners are notched out enough the have the omni wheels clear the inner face of the greeblies.  I installed a C-Channel chris-crossed on top and bottom to stiffen the board

Motor:https://www.amazon.com/gp/product/B01KTZ...UTF8&psc=1

(see my 5/12/19 post with the updated motor information)

Motor Mount Brackets:https://www.amazon.com/gp/product/B06VT8...UTF8&psc=1

The 5 inch tall carriage bolts are for the battery hold down bracket and for mounting the body to the lower section.  The 2 shorter bolts are for mounting the electronics board.

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I like to put the systems electronics onto a separate board so that I can easily remove it from the droid to bench test it. The connector at the upper left connects to the DPDT switch. I also used bolts as a bus for the positive and negative power distribution. The black strip next to the 12V to 5V step-down converter in the second pictures is a mini power distribution board I made using a short segment of 0.10 inch dual row straight pin header mounted into a flat piece of plastic and each row soldered together underneath.

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The wheels that are used on the original sentry droid are the standard VEX omni wheels.  To attach the wheel to the 6mm D-axle of the motor, I found hubs made for the motor and the fastener pattern matches the gaps between the wheel spokes.  To get the 4-40 bolts through the spokes, I had to lightly file the Vex wheel hub.  You only need to remove about .030" between each of the spokes. Don't file too deep. For the opposite side, I drilled out a large pan washer with the same pattern as the mount hub.  Also, I had to drill out the center of the Vex hub part of the way through with a 6mm (15/64) drill bit to allow the motor hun to fully engage the axle.

Motor Mount Hub: https://www.amazon.com/gp/product/B00B88...UTF8&psc=1

I also drilled a shallow dimple into the flat of the D-axle of the motor to help retain the set screw and to help prevent the hubs from slipping.

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Here is the electronics board mounted to the platform.

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Here is the battery mounted and the switch bracket.  The switch bracket is simply a bent piece of sheet metal.  You can see I cut a piece of pipe to use as a spacer to be able to tighten battery mount.  You can see the connector from the DPDT switch to the electronics.

DPDT Switch: https://www.amazon.com/Heavy-Handle-Mome...QG5GHM5Z0S

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Drive system installed onto the platform.

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To attach the drive platform to the greeblies, I used some deck screws into the step of the greeblies. I pre-drilled through the LEGO so that the screw would go in easily.

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Lower portion fully assembled.  The body mounting posts have pipe spacer and a washer so that the body can be tighten to the base without deforming the body mount points.