OmObi Bluetooth Robot Car: Arduino, HC-05 & Motor Shield – 3D Print Files (STL)

Description

OmObi Bluetooth robot car

The OmObi is a Bluetooth robot car built with an Arduino Uno, an Adafruit Motor Shield V1.2 (L293D) and an HC-05 Bluetooth module. You control it from your phone and the car drives around. Simple as that.

The chassis is 3D printed. Four geared DC motors drive the four wheels through the shield’s M1 to M4 terminals. The motor shield handles the motor drivers so you do not need an H-bridge wired up separately. The HC-05 receives commands over serial, and the Arduino translates those into motor movements: forward, backward, left, right, stop.

How the Bluetooth control works

The HC-05 pairs with your phone like any other Bluetooth device. The tutorial builds an Android app in MIT App Inventor that sends single-character commands; any serial Bluetooth terminal app works as well. The Arduino reads those characters and runs the matching motor function.

The code is straightforward, and the tutorial walks through it line by line. If you want to change the controls or add new commands, the code is easy to modify.

What can you do with this Bluetooth robot car?

The base project gives you a working platform. Some people add speed control by sending different values instead of fixed characters. Others add ultrasonic sensors to make the car semi-autonomous, avoiding walls while still accepting remote commands. A few people have used it as a starting point for a sumo bot.

You could also swap the HC-05 for a WiFi module if you want longer range, though the code would need some changes.

Printing and assembly

The chassis prints in PLA. The geared DC motors bolt to the frame with M3 screws; the Arduino holder carries the Uno with the shield on top.

What is in the package

• STL files for the chassis frame, lower and upper plate, Arduino holder, USB access cover and the cover that closes the ultrasonic sensor slots (6 files)
• Arduino code, wiring diagram and parts list: in the free step-by-step tutorial (link below)

Full tutorial: OmObi Bluetooth Robot Car Build Guide