Digital Lock with Easter Eggs
How it works
This project implements a 4-bit digital lock with additional "Easter egg" outputs for near-miss patterns.
Inputs
IN0 = Least significant bit of the 4-bit codeIN1 = Second bit of the codeIN2 = Third bit of the codeIN3 = Most significant bit of the code
Outputs
UNLOCK = Goes high when the entered code is exactly 1011EASTER0 = Goes high when the code is 1010 (one bit off)EASTER1 = Goes high when the code is 1001 (one bit off)EASTER2 = Goes high when the code is 0011 (different pattern)
Logic Implementation
- Purely combinational logic
- Uses 2-input AND gates and NOT gates
- Each output detects a specific pattern using AND/NOT combinations
- No clock or sequential logic is used
How to test
- Open the project in Wokwi.
- Toggle the input switches (
IN3 to IN0) to enter a 4-bit code.
- Observe the output LEDs or 7-segment display:
| Input Code |
UNLOCK |
EASTER0 |
EASTER1 |
EASTER2 |
| 1011 |
1 |
0 |
0 |
0 |
| 1010 |
0 |
1 |
0 |
0 |
| 1001 |
0 |
0 |
1 |
0 |
| 0011 |
0 |
0 |
0 |
1 |
| Other |
0 |
0 |
0 |
0 |
- Only the correct pattern should activate UNLOCK.
- The Easter outputs show “near-miss” patterns and should be low for the exact code.
