Tutorial 12 — PPE Compliance Detection (Hard Hat & Vest) with Jetson

Automatically detect whether workers on a construction site or factory floor are wearing the required PPE — hard hats, safety vests, and gloves — and alert supervisors in real time when violations occur.

What you will learn

• How to train a custom PPE detection model (hard hat, vest, no-hat, no-vest)
• How to detect multiple PPE classes simultaneously in one inference pass
• How to trigger alerts only after a sustained violation (avoiding false alarms)
• How to send email or MQTT alerts with a snapshot of the violation
• How to log all violations to a database with timestamp and camera ID

Step 1 — Run the PPE compliance demo

cd ~/tutorials/12-ppe-compliance
python3 ppe_monitor.py --source 0 --show --alert-threshold 3

The system detects people and immediately checks whether they have a hard hat (shown in green) or are missing one (shown in red). If a violation persists for 3 seconds it triggers an alert.

Step 2 — PPE detection classes

PPE_CLASSES = {
    0: 'hard-hat',    # ✅ compliant
    1: 'no-hard-hat', # ❌ violation
    2: 'safety-vest', # ✅ compliant
    3: 'no-vest',     # ❌ violation
    4: 'gloves',      # ✅ compliant
    5: 'no-gloves'    # ❌ violation
}

for box in results[0].boxes:
    cls  = int(box.cls)
    conf = float(box.conf)
    if cls in [1, 3, 5] and conf > 0.7:   # violation detected
        trigger_violation_alert(cls, frame)

Step 3 — Sustained violation alert (debounce)

from collections import defaultdict
import time

violation_start = defaultdict(lambda: None)
ALERT_AFTER_SECS = 3

def check_sustained_violation(person_id, is_violation):
    if is_violation:
        if violation_start[person_id] is None:
            violation_start[person_id] = time.time()
        elif time.time() - violation_start[person_id] > ALERT_AFTER_SECS:
            send_alert(person_id)
            violation_start[person_id] = None   # reset
    else:
        violation_start[person_id] = None   # clear if compliant

✅ Next: Tutorial 13 — Face Blur Privacy Pipeline | Back to Jetson Kit