In this instruction I will present you design of omni wheel mobile robot controlled via wi-fi. The essential difference compared to conventional control like bluetooth or radio control is that the robot is connected to local area network (LAN) and can be used as mobile IoT device. The heart of the system is Arduino Mega 2560 and Dragino Yun Shield. Dragino Yun is based on OpenWrt Linux and gives a few useful functionalities. One of them is the ability of over the air code upload to Arduino board. It can be also managed by Web GUI and SSH, and has built-in web server.
In this project I used 4 continuous rotation servos controlled by Mini Maestro 12-channel servo controller. By the way I wanted to test movement of robot with omni wheels, so I used four 40mm Dagu omni wheels. This mobile robot is equipped with two power sources. One for supplying the servos (Power bank 10000 mAh) and the other to supply Arduino and Dragino (Li-Po battery 1800 mAh).
To build the robot chassis I've used a piece of steel plate with a thickness of 2 mm and a piece of pvc plate with a thickness of 5 mm. Then I joined the two plates with screws for construction reinforcement. Additionally I've glued the servos to the base using adhesive tape.
Components of the project:
Arduino Mega 2560 is connected with Dragino Yun Shield, but firstly you have to disconnect the uart connection between mega2560 and mega16u2 as shown in this link.
The next step is wired connection between Arduino Mega and Mini Maestro 12 as shown in the picture above.
1. Arduino Mega 2560 -> Mini Maestro 12
2. Battery 5V (Power bank) -> Mini Maestro 12
3. Servos -> Mini Maestro 12