Sparkfun sell some nice little omniwheels made by FingerTech Robotics. These come with a grub screw mount for a 3mm axle. While it is said around the webs that one might drill out the mount to accept up to a 6mm axle, I wanted a more flexible solution for mounting these wheels onto an Actobotics structure. It turns out that the four screw mounts (using what I think are x-40 screws) are in an extremely close location to the four screws on the Actobotics hub mount. Unfortunately it was a tad hard for me to get a hold of longer x-40 screws to attach the hub mount, so I ended up taking the wheel apart and replacing the standoffs with the Actobotics ones. The result is shown below:
Actobotics Robo Claw 2x5a Motor Controller Driver 9 Volt Dc Motor Vehicle
The RoboClaw motor controllers from Basicmicro (formerly Ion Motion Control) can control a one or two brushed DC motors using USB serial, TTL serial, RC, or analog inputs. Integrated dual quadrature decoders make it easy to create a closed-loop speed control system, or analog feedback can be used for position control. Dual motor driver perfect for controlling two bidirectional DC motors Can also be used to control a single bipolar stepper motor Recommended motor voltage (VMOT): 4.5 - 13.5 V.
The below shows the mecanum wheel taken apart. The three standoffs you see vertical in the image are the original ones from the wheel. These are about 1 inch long, so you'll be wanting some 1 inch actobotics standoffs to replace them with. When you unscrew the original standoffs then the hub mount part (centre of the red alloy), will be able to fall out and be removed. This lets you screw the Actobotics standoffs on and then on the other side use slightly longer bolts to attach the hub mount to the wheel to get the assembly shown above.Actobotics Roboclaw 2x5a Motor Controller Driver 9 Volt Dc Motor Vehicle
Actobotics Roboclaw 2x5a Motor Controller Driver 9 Volt Dc Motor Battery
Apart from a clean 6mm hookup for the stepper motors that I plan to use, this is a handy modification allowing the 1/4 inch hub mount or other sizes to be substituted in instead. This is handy if you want to switch from 6mm to 6.35mm (1/4 inch) axles as you can easily change your mind just by changing the actobotics hub mounts.
Actobotics Robo Claw 2x5a Motor Controller Driver 9 Volt Dc Motors
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