6-DOF Robotic Arm with Bluetooth (HC-05) – 3D Print and CAD Files (STL + STP)

Description

6-DOF Bluetooth robotic arm

This is the Bluetooth version of the 6-DOF robotic arm. Same mechanical design, but now you can move every joint from your phone over an HC-05 Bluetooth module.

The arm has 5 rotational axes and a gripper, powered by MG996R and SG90 servo motors. A PCA9685 servo driver handles all the PWM signals, and an Arduino Uno runs the show. The HC-05 connects to the Uno’s serial pins and listens for movement commands sent from a Bluetooth terminal app on your phone.

How does the Bluetooth control work?

The Arduino code reads incoming serial data from the HC-05 and maps it to servo positions. The command format is servo,angle: 2,90 moves servo 2 to 90 degrees. The RobotArmControl Android app from the tutorial (MIT App Inventor, on GitHub) sends these commands; any Bluetooth serial terminal app works too. The HC-05 hangs on SoftwareSerial pins 10 and 11 with a 1 kΩ/2 kΩ divider on its RX line.

You can save up to 10 arm poses from the app and replay them once or in a loop. The code is commented, so editing it for your own use should not be a headache.

What is different from the basic version?

Same joint layout as the basic arm; this package holds the revised base and arm links with a printed joint pin (13 STL files per version). If you already built the basic arm, the upgrade is the HC-05 wiring and the new sketch.

Printing and assembly

Same PLA settings as the basic arm: 0.2 mm layer height, at least 40 % infill for base and arm links, 20 % for the gripper gears. Assembly uses M3 hardware, a few self-tapping screws and one 6806ZZ ball bearing (30x42x7 mm) in the base.

What’s included

• 13 STL files per version (two folders: with and without the centralization ring), README and LICENSE
• Arduino code, wiring diagram and parts list: in the free step-by-step tutorial (link below)

Full tutorial: DIY 6-DOF Robotic Arm with Bluetooth Control