Arduino project · Smart doors and home · Easy
Bluetooth Door Latch
The ON button unlocks the latch (green) and OFF locks it again (red).
What you will learn
- How to control a latch from a phone
- Why pairing and a password matter
- How feedback LEDs help
How it works
The servo starts locked at 0 degrees. A command ON moves it to 90 degrees and lights the green LED. OFF moves it back and lights the red LED.
Try this next
- Add a second button for a different latch.
- Make it close automatically after 10 seconds.
- Think about what would make this safe for a real door.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
A door with an electronic lock
When the right card, finger, code or button opens the lock, the door in the real scene swings open and the green light shows.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Servo = the door lock
- Green LED = access allowed
- Red LED = door locked