Couldn't resist buying this Microbot MiniMover-5 model MIM-5 from eBay.

Dates back to the 1980s and would have been a competitor in same market sector as the Colne Robotics Ltd. ARMDROID 1 for light industrial and educational use.   This table-top, 5 axis manipulator arm was designed & manufactured by Microbot Inc. of Menlo Park, California, USA.

I was intrigued to see how this design differs.... The hand assembly appears to be of much higher precision, better build quality, and rather nicely, incorporates a micro-switch tension feedback mechanism making this ideal for pick-and-place applications.

The whole construction is slightly more compact, lighter in weight, with major structural components made out of thinner gauge folded steel sheet.  This example has a see through perspex base allowing you to see inside – not sure if this is standard, or a later modification?

The gearing and pulleys, also made from DELRIN are similar, but its difficult to tell the exact gearing ratios without stripping down the mechanism.  Gripper Roll & Pitch movements are basically the same as the Armdroid.

Powered by six uni-polar stepper motors, with power transmitted using pulleys and plastic coated steal cables with tensioners, this is probably less likely to snap, which is a real source of irritation when operating the Armdroid 1.   A real differentiator with this design is the handling of Base rotations.  The motor for this axis is actually mounted in the shoulder and uses a rather intriguing method of cables/pulleys feeding into the base to perform rotations, but limited to 180 degrees of freedom.

Looking at the electronics - interface board is very similar in concept, address decoding routes data to channel latches driving each stepper motor through Darlington Driver Arrays.  Feedback from the gripper switch and auxiliary inputs are returned on a separate 4-bit data bus, which appears to be a separate bus from the inputs.

Designed to connect directly to the TRS-80 expansion port, or any 8-bit microcomputer with suitable interface circuitry.  Required powering from a single 12v source capable of at least 4Amps, although this was not included.

I'm guessing arm was not sold as a kit, but ready assembled, although I do have some rather nice exploded drawings.

The instruction manual I have describes the original software as a variant of basic, called ARMBASIC and appears to be far more comprehensive than Colne Robotics equivalent.

General Characteristics:
Resolution 0.013” (0.3mm) maximum on each axis
Load Capacity 8 oz (225 gm) at full extension
Gripping Force 3 lbs (13N) maximum
Reach 17.5” (444mm)
Static load force 4 lbs (18N) maximum
Arm weight 3 Kg
Interface cable length 3' (900mm)
Power requirement 12 volts, 4 Amp DC

Not a great deal of information can be found on the internet, but the following is a nice video demonstrating this robotic arm in operation being controlled by a Microchip PIC18F micro-controller:  Mini mover 5
Microbot MiniMover-5
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