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arduino-knock-knock-door-access-system-f3f178-en.md

I was watching Stranger Things Season 2, there was a scene where one of the characters in the show was using a secret knock on the door to let the other person in the house know it was him.

At this point, I know I have a peculiar interest in making very 'puzzling' projects haha 🤣

Then I recalled I have a digital/analog sound sensor lying around. Hence, this project was created in a span of three days!

I really hope someone could implement it much better than I do since I have very limited resources (and space in the house) to do this.

Do watch the video below to see how it works!

Watch this video to see how it works!

EXPANDED TECHNICAL DETAILS

Acoustic Pattern Recognition

This biometrically-inspired lock identifies users based on a secret rhythmic sequence (a "Secret Knock").

  • Vibration Sensing: Uses a Piezoelectric transducer attached to the inside of the door. The Arduino monitors the analog voltage spikes; each "Knock" creates a spike that is recorded with a microsecond-precision timestamp.
  • Pattern Matching Logic: The firmware compares the intervals between knocks rather than the volume. If the rhythm matches the secret code stored in EEPROM within a 10% timing tolerance, the door unlocks.

Physical Actuation

  • Solenoid Drive: Upon a valid match, the Arduino triggers a 12V Solenoid Deadbolt via a logic-level MOSFET or Relay.
  • Feedback Loop: Includes a multi-color LED; blinking yellow for "listening," green for "access granted," and a long red pulse for "incorrect rhythm."

ข้อมูล Frontmatter ดั้งเดิม 

title: "Arduino 'Knock Knock' Door Access System"
description: "Use 'secret knocks' to enter a room!"
author: "c010rblind3ngineer"
category: ""
tags:
  - "audio"
  - "security"
views: 1583
likes: 0
price: 1120
difficulty: "Intermediate"
components:
  - "3x Resistor 220 ohm"
  - "1x Breadboard (generic)"
  - "3x 5 mm LED: Green"
  - "1x Tactile Switch, Top Actuated"
  - "1x KY-037 (Digital/Analog Sound sensor)"
  - "1x I2C 16x2 Arduino LCD Display Module"
  - "1x Resistor 10k ohm"
  - "1x Jumper wires (generic)"
  - "1x Arduino UNO"
tools: []
apps:
  - "1x Arduino IDE"
downloadableFiles:
  - "https://github.com/c010rblind3ngineer/Knock2DoorAccess.git"
  - "https://github.com/c010rblind3ngineer/Knock2DoorAccess.git"
documentationLinks: []
passwordHash: "d5bc600fc5ebd125faba6c88fc5157742968b477e837cfb054e942e5932c4612"
encryptedPayload: "U2FsdGVkX1+d86UN5ecZxMqX8PksxA4W3dMEMmaCcutq8jrtgjNlmFAqecXdN/l1HOTYL1/x45fCXEFl2lp3YJYW0VL6JEFqs3c2624g9u0="
seoDescription: "Create an Arduino Door Access system using 'secret knocks'. Secure your room with custom patterns and DIY hardware."
videoLinks:
  - "https://www.youtube.com/embed/PStRo1I2_PE"
heroImage: "https://cdn.jsdelivr.net/gh/bigboxthailand/arduino-assets@main/images/projects/arduino-knock-knock-door-access-system-f3f178_cover.jpg"
lang: "en"