How to Select Micro Gear Motors for Smart Door Locks

# How to Select Micro Gear Motors for Smart Door Locks The motor is the single most critical component in a smart lock. It determines reliability, battery life, security, and user experience. Here's how to choose the right one. ## The 4 Critical Factors ### 1. Battery Life Smart locks operate on 4×AA batteries for 6-12 months. Your motor must draw minimal current. - **Target:** <80mA no-load, <400mA stall - **Recommendation:** N20 Metal Spur, 6V winding ### 2. Noise Nobody wants a loud lock on their front door. - **Target:** <50dB at 30cm - **Recommendation:** Precision-ground metal spur gears ### 3. Anti-Tamper Security Can an attacker push the bolt back from outside? If your lock mechanism can be back-driven, you have a security vulnerability. - **Solution:** Worm gear self-locking motor — cannot be back-driven by design - **Recommendation:** N20 Worm Self-Lock, 200:1 ### 4. Cycle Life Hotel locks need 100K+ cycles. Residential locks: 20K-50K. - **Standard:** N20 Metal Spur: 50K+ cycles - **Extended:** N20 Planetary: 100K+ cycles - **Maximum:** N20 Planetary + premium lubrication: 200K+ cycles ## Quick Selection Table | Lock Type | Recommended Motor | Key Reason | |:---|:---|:---| | Residential fingerprint (cost-sensitive) | N20 Metal Spur 100:1, 6V | Best value, proven | | Premium fingerprint (smooth, quiet) | N20 Planetary 64:1, 12V | Low backlash, premium feel | | High-security deadbolt (anti-tamper) | N20 Worm Self-Lock 200:1 | Cannot be back-driven | | Hotel lock (high cycle) | N20 Planetary 64:1 + Hall Encoder | 200K+ rated, position feedback | [Explore smart lock motor solutions →](/solutions/smart-lock-micro-motor-solution)