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Opto-isolation boards have been added to protect the Arduino board on start up
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springs on the cable tension sensors have been replaced with rubber bands (more tension / easier)
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Controller Arduino board now mounted on standoffs on a plastic base
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TODO: circuit needed to detect open/closed connection for the cable tension switches that won't damage the Arduino
Things are in alpha stage but are progressing.
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Instead of the standalone motor position sensor boards with 3D printed holders I found an integrated solution: MKS Stepper Motor Servo Stepping Controller SMT32 Step PCB Board Nema17 SERVO42C PCBA OLED CNC Closed Loop https://www.aliexpress.com/item/1005004149466760.html?spm=a2g0o.order_list.0.0.354418029ptywh
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Driver connection boards Stepper Motor A4988/DRV8825 Driver Control Extension Shield Boards https://www.aliexpress.com/item/32641758432.html?spm=a2g0o.order_list.0.0.354418029ptywh
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(pending) will be working on integrating the Opto-isolator IC Modules so if the motors are powered up before the Arduino board the Arduino board doesn't get damaged. That happened to me I think and I had to swap out the Arduino.
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installed tendon slack sensors; but stronger springs probably needed:
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A functional but pretty useful upgrade are the NEMA 17 brackets NEMA 17 Steppr Motor Accessories Plastic Bracket Support Mounting L Type Bracket https://www.aliexpress.com/item/1005002788453321.html?spm=a2g0o.order_list.0.0.354418029ptywh
I have moved away from pyfirmata and have adapted some code directly written on the Arduino due to serial communication issues. I'll be thinking about and exploring JSON or ROS directly if feasible -- I'll see what custom driver code is needed. The motors move on command, but movement relationship between tendon and arm endpoint has not been established yet on the system.
Image of the current setup:
