The Tandy (Radio Shack) Armatron
Bob's hacked version. Details follow...
Disassembly. Note box of removed parts on right
Complex gearing using only ONE motor (gold thing at right center)
Just the arm without base
Close up of gripper. Requires multiple turns on pinion to open and close
My version. Would have worked with a servo on top of one gear
Here's the gripper I used.instead..found it in my junk parts bin
This would have worked with a counterweight. As it was, there was too much torque required to lift the arm with gear ratio shown.
Moved servo, changed gear ratio and added counterweight (not shown)
That little spring took up some of the flex in the plastic, keeping gears meshed.
I used Tower Pro MG996R servos for the high torque joints and these smaller SG90 for the lower torque joints, the "wrist" and the gripper.
Video of Armatron going through it's movements: Computer Controlled Armatron
Video of Armatron gripper only: Armatron Gripper
(Sequencing done with Lynxmotion Visual Sequencer and SSC32U servo controller)
I had a Tandy Armatron mechanical arm for many years, stored away because "someday" I was going to convert it to computer control. Well that day arrived a few months ago. Here are some photos showing the work involved. Likely I will take this apart (after months of work) and use the servos for something else because, though it works, the Armatron is not practical because of all the plastic components. There are forces and stresses involved that bend the plastic, thus making it inacurate for "work".
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