M100RAK Robotic Arm Kit User Guide
RobotShop Inc. www.RobotShop.com
Useful Links
Hitec HS-785HB Servo Motor:
http://www.robotshop.ca/PDF/HS-785HB.pdf
Robot Arm Torque Calculator
http://www.robotshop.com/robot-arm.html
Robot Arm Torque Tutorial
http://www.robotshop.com/robot-arm-torque-tutorial.html
Troubleshooting and contact (select technical support):
http://robotshop.helpserve.com/index.php?_m=tickets&_a=submit
FAQs
Q1) Can I use other servo motors with this arm?
Only the Hitec HS-785HB and Hitec HS-755MG can fit the space. The 755MG would only be
able to rotate 36 degrees without modification.
Q2) What other parts are required to make a “robotic” arm?
You would need a standard servo motor controller capable of providing sufficient current, as
well as a 4.8V to 6V power supply. We also suggest a clearly labelled “kill switch” to stop all
power to the arm.
Q3) Can the joints rotate 360 degrees?
Sending a signal between 501us and 600us causes the servo to rotate (501 is very fast to 599
is very slow). A pulse between 2401us and 2500us causes it to rotate in the opposite direction.
Note that only the base is really able to rotate 360 degrees without being physically impeded.
Q4) Are other gear ratios offered? Can I choose the specific gear ratio for each joint?
Yes, but it is special order. A full metal geardown is also available.
Q5) Why didnt you include a gripper with the basic kit?
Given the range of tasks the arm can be used for, including a gripper would have increased the
price. A gripper may be released at a later date.
Q6) How do I configure the arm to make it as accurate as possible?