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TecArm6v2 by David Buckley 2012
Thinking that the Fablab Manchester might open a webshop I redesigned the prototype of the TecArm6 I created for Milford Instruments in 1999.

I siffened the limbs and added sliding feet for the waist movement to ease the strain on the servo-horn a made the gripper gear driven to balance the finger movement. The shop never materialised so the TecArm6v2 was put back on the shelf.

In 2020 during Covid lock-down I was talking to a friend who had purchased a hobby robot-arm from China and decided to look at my TecArm6v2 again. The original GUI written by Milford no longer worked in Windows-10 so I added an Aduino nano to accept high level commands from a serial-terminal and send the necessary codes to the existing servo controller on the arm. (I did the same for the TecArm5 prototype.)
The commands can be received over USB but because when the arm moves the cable could be pulled and damage the socket I added a standard RS232 D9.

The original TecArm control board (green) accepts, through its D9 connector, RS232 serial data in Scott Edwards' three byte format.
- Byte 1 255 (Synchronization byte)
- Byte 2 Servo # (0-7) (Address jumper out)
- Byte 3 Servo Position (0-254)
- eg the following string will send servo 6 to the mid point of its travel:
- <255> <6> <127>


  Upper Arm    - Shoulder to elbow   =  90 mm
  Fore Arm     - elbow to wrist      = 125 mm
  Hand         - Wrist to fingertips = 100 mm
  Gripper      - opening             =  85 mm

  At 125mm extension          - lift = ~450 g
  At maximum extension ~315mm - lift = ~200 g


  Waist       HiTEC  HS-755HB       4.8/6v  0.28sec,0.23sec   8.8kg.cm(122.2oz.in), 10.5kg.cm(145.81oz.in)
  Shoulder    HiTEC  HS-805BB       4.8/6v  0.19sec,0.14sec  19.8kg.cm(275.09oz.in),24.7kg.cm(343.36oz.in)
  Elbow       HiTEC  HS-755HB       4.8/6v  0.28sec,0.23sec   8.8kg.cm(122.2oz.in), 10.5kg.cm(145.81oz.in)
  Wrist pitch JP SuperTec  S06/2BB  7.2Kg.cm @4.8v, 8Kg.cm @6v
  Wrist turn  JP SuperTec  S03      3.4Kg.cm @4.8v, 4Kg,cm @6v
  Gripper     JP SuperTec  S03      3.4Kg.cm @4.8v, 4Kg,cm @6v

Because the servos are so easy to backdrive it collapses with no power so arbitrary poses with no power are not possible, it has to be supported, either by itself or the ground etc.