Network Connected Lock

thingiverse

This mechanism was designed to lock and unlock a door by mechanically turning the lock cylinder using a servo motor controlled by an Arduino. A wireless Arduino shield is used to allow for remote locking and unlocking from a mobile phone app through network connectivity established with a SmartThings hub via a Zigbee network. The prototype's mechanics is based on the Worm Gear Reducer, a design published by Mattheus on Thingiverse (https://www.thingiverse.com/thing:41161). This is an initial prototype using a simple HS-311 servo motor converted into a continuous rotation servo for improved performance. Mechanics remain simple and reliable while providing adequate torque to turn the lock with minimal current draw, making it feasible to be driven directly by the Arduino. The mechanism takes its time (over one minute) for a full turn of the key. This design intentionally sacrifices speed in favor of torque to use a relatively small and weak servo motor that can easily handle the task at hand without the need for any significant external current sourcing or specialized power supplies beyond the standard provided with portable USB chargers. Design files were generated using Sketchup. Links are available on 3D Warehouse so users can access the Sketchup models (e.g., to modify the design and adapt it to other lock types) at https://3dwarehouse.sketchup.com/model.html?id=u49c8e7b9-ba90-4d48-9280-3fb5b7a23cf7. **Printer Settings** **Printed Parts Details** - **Manufacturer:** RepRap - **Model Name/Type:** Prusa I3 Printing settings: - Rafts: No - Supports: No - Layer Thickness: 0.2mm - Infill Levels: 20%, 40% Assembly and Setup: I used ABS for all the printed parts, using a worm gear fill level of 40% while all other components utilized 20% infill settings at a standard 0.2mm layer thickness. **Bill of Materials** For completion: * Arduino Board * SmartThings Arduino Shield or similar connectivity solution * HS-311 Servo Motor * Portable USB Charger * Two Pushbuttons for local control and the removal of the necessity to rely on mobile apps. * M3 screws and corresponding nuts in a range of lengths to suit different assembly requirements (e.g., 50mm, 30mm). * Double-sided adhesive tape Some cable is required to ensure connections are secure. Printed servo adapters should be placed on the motor shaft tightly; they must have the right diameter. To get this correctly, you might need to use a drill with a diameter of 5.5 mm, once you’ve achieved the desired measurement you should screw these two m3X5 screws to hold it securely in place. Servo motors require modifications to be continuous rotation; please visit this website for instructions: https://www.flickr.com/photos/randomskk/2569969633/. Arduino sketch includes various parameters to fine-tune movement time, speed, and angle according to your specific lock mechanism’s requirements. These need adjustments so the assembly can be customized precisely for optimal performance in real-world use cases.