A Raspberry Pi OS–runnable Python 3 rover stack that:

1. Teleoperates via a simple Flask web dashboard
2. Scans obstacles using HC-SR04 mounted on an SG90 servo
3. Builds a local 2D obstacle map (occupancy grid + point overlay)
4. Estimates “possible human nearby” using Wi-Fi scanning (RSSI / device activity score)

GPIO12 is shared:

• Servo signal: GPIO12
• TB6612FNG LEFT motor PWMA: GPIO12

This code enforces an explicit PWM ownership lock so:

• Motors are fully stopped and motor PWM is disabled before sonar scanning begins
• Servo PWM exists only during scanning, then is stopped and released
• Motor PWM is re-enabled only after scanning completes
• Servo PWM and motor PWM are never active on GPIO12 at the same time

• Servo: GPIO12
• HC-SR04 TRIG: GPIO23
• HC-SR04 ECHO: GPIO24 (must be reduced to 3.3V with a voltage divider)
• TB6612FNG:
  • STBY: GPIO25
  • LEFT: PWMA GPIO12, AIN1 GPIO5, AIN2 GPIO6
  • RIGHT: PWMB GPIO13, BIN1 GPIO20, BIN2 GPIO21

1. Update packages:

sudo apt update
sudo apt install -y python3-pip python3-pil

2. Install Python deps:

pip3 install flask pillow

RPi.GPIO is typically preinstalled on Raspberry Pi OS.

Wi-Fi scanning via iw dev wlan0 scan usually requires root.

HC-SR04 ECHO must go through a voltage divider to 3.3V before connecting to GPIO24.

TB6612FNG requires proper VM motor supply and common ground with Raspberry Pi.

Always run with sudo for Wi-Fi scanning stability:

sudo python3 main.py

Open: http://:5000

If motors do not move:

Confirm TB6612 STBY is HIGH (code sets it when enabled)

Confirm motor power supply is connected and GND is shared

Confirm AIN/BIN pins match wiring

If servo jitters:

Ensure adequate 5V supply for servo (do not power SG90 from Pi 5V if brownouts occur)

Increase SERVO_SETTLE_S in config.py

If Wi-Fi scan is empty:

Ensure wlan0 exists: ip a

Ensure iw is available: which iw

Run as sudo

• config.py
• controllers/motors.py
• sensing/sonar.py
• mapping/occupancy_grid.py
• signals/wifi_scan.py
• ui/webapp.py
• main.py
• static/map.png (generated at runtime)

Forward motion is blocked when the latest scan indicates an obstacle <= FRONT_STOP_CM in the forward sector (angles 80..100).

Manual commands disable autonomous mode to prevent PWM contention on GPIO12.

1. Motor test

sudo python3 main.py --motor-test

2. Sonar scan test

sudo python3 main.py --sonar-test

3. Run main dashboard

sudo python3 main.py

Open: http://:5000