OmObiArm: Mobile Robot Arm with Arduino & Bluetooth

Description

OmObiArm: mobile robot arm

The OmObiArm is a mobile robot with a robotic arm mounted on top. Think of it as the OmObi robot car with a 6-DOF arm bolted to the chassis. You drive it around over Bluetooth and control the arm at the same time.

The base uses two DC motors and a caster wheel, same as the OmObi. The arm sits on a rotating platform and has the same joint layout as the standalone robotic arm: 5 axes plus a gripper, running on MG996R and SG90 servos. Everything is controlled through an Arduino Mega because the Uno does not have enough pins for both the drive motors and six servo channels.

How it works

An Adafruit Motor Shield handles the DC drive motors. The arm servos connect to a PCA9685 PWM driver over I2C. An HC-05 Bluetooth module handles wireless communication. You send commands from a serial Bluetooth app on your phone, and the Arduino parses them to either drive the wheels or move a specific servo.

The code keeps driving and arm control separate so they do not interfere with each other. You can drive while repositioning the arm.

Printing the parts

This is a bigger print job than the other projects. The chassis, arm brackets, and platform add up to about 30 to 35 hours of print time, depending on your settings. I recommend PLA with 30% infill for structural parts. The arm pieces are the same STL files as the standalone arm project, plus extra parts for the chassis and the mounting platform.

STP files are also included if you want to modify the design in your own CAD software.

Assembly notes

Wiring this one takes patience since there are more connections than the standalone arm or the basic robot car. The wiring diagram covers every single connection. Budget about two to three hours for the full assembly once everything is printed.

What’s included

• STL and STP design files for all parts
• Arduino code for the drive base and robotic arm
• Wiring diagram and full parts list

Full tutorial: OmObiArm: Mobile Robot Arm with Bluetooth