🤖 mBot2 Sumo Robot

Autonomous sumo robot programmed in Python (MicroPython) for the Makeblock mBot2.

How it works

The robot operates in 3 states that switch automatically based on sensor input:

• 🔵 SEARCH — Spins slowly until the opponent is detected by the ultrasonic sensor
• 🔴 ATTACK — Drives forward at full speed to push the opponent out of the ring
• 🟠 ESCAPE — If the black edge of the ring is detected, backs up and turns 180° to return to the center

Repository structure

mbot2-sumo/
├── mbot2_sumo.py              # Main sumo program
├── README.md
└── tests/
    ├── test_ultrasonic.py     # Reads and prints ultrasonic distance
    ├── test_line_sensor.py    # Reads and prints line/edge sensor status
    └── list_sensor_methods.py # Lists all available methods on the line sensor

The tests/ scripts are optional but recommended. mBot2 firmware versions vary, and some sensor functions (get_value, get_grey, get_color_sta, etc.) may or may not exist depending on your unit. Run these first to confirm which functions work on your robot before trusting the main program.

Required hardware

• mBot2 (CyberPi + Chassis)
• Ultrasonic sensor (port 1) — detects the opponent
• Quad RGB sensor (port 1) — detects the black edge of the ring

Step-by-step: how to upload the code

1. Install mBlock (desktop app) if you haven't already: https://www.mblock.cc/en-us/download
2. Connect the mBot2 to your computer via USB cable
3. Open mBlock and make sure the device is detected in the bottom-left device panel
4. In the top toolbar, switch from Live mode to Upload mode — this is critical. Live mode only runs code while connected to your PC; Upload mode saves the code permanently onto the robot so it works standalone in the ring
5. Click the Python tab (not Blocks) in the code editor
6. Paste the full contents of mbot2_sumo.py
7. Click Upload and wait for the confirmation
8. Disconnect the USB cable
9. Place the robot inside the sumo ring
10. Press the A button on the CyberPi screen to begin the 3-second countdown
11. The robot starts fighting automatically

If you get sensor errors

If the screen shows something like 'module' object has no attribute 'xxxx', your firmware version uses different method names. Upload the scripts inside tests/ one at a time to discover which functions actually exist on your unit, then update mbot2_sumo.py accordingly.

Adjustable parameters

Parameter	Value	Description
VEL_ATAQUE	100	Attack speed (0-100)
VEL_BUSCAR	40	Search rotation speed
VEL_ESCAPE	80	Speed when escaping the edge
DIST_RIVAL	40	Distance in cm to detect the opponent
CONFIRMACIONES_SIN_RIVAL	40	Readings without opponent before returning to search (~2 sec)
CONFIRMACIONES_BORDE	3	Consecutive black readings before escaping

Line sensor behavior

The quad RGB sensor returns the string "black" when it detects the ring's black edge. Three consecutive confirmations are used to avoid false positives on white flooring.

Notes

• The code was developed and debugged live by testing each function directly on the robot, since the cyberpi and mbuild libraries only exist inside the mBot2 firmware — they cannot be run or linted on a regular computer.
• The correct functions for motor control are cpi.mbot2.forward(), backward(), turn_left(), turn_right().
• The ultrasonic sensor is read with mbuild.ultrasonic2.get(1) using a numeric port.
• The line sensor is read with mbuild.quad_rgb_sensor.get_color_sta(channel, port).