This is a simple electronic code lock. The output of the lock in this example is an LED that turns on when you input the right code. But you can replace the LED with a transistor and control a real mechanical lock too.
The Circuit
The NOT-gates and AND-gates are combined so that the output is true only if you input the code 1001 using the switches on the DIP switch.
Parts List
| Reference | Value |
|---|---|
| Battery | 9V |
| D1 | Light-Emitting Diode (LED) |
| R1 | 1k |
| R2 | 1k |
| R3 | 1k |
| R4 | 1k |
| R5 | 1k |
| SW1 | 4-position DIP Switch |
| U1 | CD4069 |
| U2 | CD4081 |
The Layout
