Douglas Santana's SynArm Puts Low-Cost Robot Arms Under Contact-Free Control, Thanks to Leap Motion
With keyboard and joystick fallback, this gesture-based robot arm control system targets devices built on low-cost hobby servos.
Electrical engineer Douglas Santana has released a tool designed to control low-cost six-degrees-of-freedom (6DoF) robot arms through keyboard, joystick, or hand-tracking inputs: SynArm.
"SynArm is a multimodal control framework for a 6DoF robotic arm that targets low‑cost hobby servos (TD8120MG) driven by a[n NXP Semiconductors] PCA9685 PWM [Pulse-Width Modulation] expander. The project integrates Leap Motion gestural input, joystick/keyboard fallback, real‑time 3D visualisation in Processing 4, and an Arduino UNO‑based firmware that also supports a stepper‑driven linear axis and on‑board inertial sensing ([TDK InvenSense] MPU6050)."
Controlling a robot arm — either by telling it how to move or where you want it to go — can sometimes by a thorny problem, with neither keyboard, mouse, nor joystick particularly well-suited to devices with more than two axes of motion. SynArm aims to fix that by targeting a different input: the Leap Motion hand-sensing controller, which sits on a desk or keyboard and tracks one or two hands as they move.
Santana's system uses the Leap Motion to track both movement and gesture, allowing the controller to make a pinching motion to open and close the arm's gripper and to twist and tilt their hand to have the arm mimic the movement. Among the project's stated goals are "intuitive, contact-free control with dual-hand tracking," Santana explains, "[with] deterministic servo timing (±2 µs) and stable positioning even under load" plus "collision‑aware rendering that caps angles when boxes intersect."
The project has been published on GitHub under an unspecified open source license, with plans for further development including the addition of a second stepper channel and the implementation of inverse kinematics with target-point dragging.
