Color Combination Lock

Color Combination Lock
A rather diabolical color combination lock. Someone can watch you enter the combination, and then not be able to do it themselves. The combination appears different each time due to insertion of random color digits. The combination is not positional (the digit positions change every time).

This is a one-off build to experiment with the color lock concept. The lock control output doesn't connect to anything at this time.

Features

• 4 buttons, 7 possible colors each.
• Up to 10 combination digits.
• Observer Obfuscation logic.

Operation
This is a combination lock, not a puzzle. The combination is a number of color digits keys in sequence, for example red,green,blue.

• The locked display is all red; press any key to start.
• Press the next color in sequence if it appears; if it doesn't appear, press any color.
• When the combination is entered correctly, all will flash green for 30 seconds and the door latch output pin will go high.
• If the code is wrong, it continues to prompt randomly.
• To restart, press any two buttons simultaneously.

Changing the Combination
Use the serial monitor or other serial terminal (9600 baud). Enter "combination=x", e.g. combination=rgbw The color letters are r,g,b,w,m,a,y (red,grn,blu,whi,mag,aqua,yel).

Design Documents

Arduino Code	Arduino.ino
3D Print Files	Color Lock STL Files.zip

This is so simple that there is no schematic. It's just 5 wires to the Arduino:

• LED string to Pin 4
• Button 1 to Pin 5
• Button 2 to Pin 6
• Button 3 to Pin 7
• Button 4 to Pin 8
• And of course power to the Arduino and LED string

Bill of Material

• Arduino Pro Mini 5V/16MHz
• (4) Pushbutton Switches
• String of 30/m ARGB LEDs
• Perfboard
• 2.1mm Barrel Jack
• Shell (3D printed)
• Spacer (3D printed)
• Keys (3D printed)

Build Pictures

Top View

Perspective View

Interior

Assembly