Hey

Mechatronics Engineering is a mix bread between mechanical,  electronic and electrical. 

So the engineer can work in mechanical,  electrical,  and electronic field. He includes robotics,  telecommunications,  control system,  AI. 

The mechatronics engineer can work in following field. 

1. Machine vision

2. Automation and robotics

3. Servo mechanisms

4. Automotive electronic

5. Industrial robot

6. Microcontroller 

7. PLC

Etc 

Basically he can design any mechanical systems and work on electronic on it and their after program it.