230 Digital padlock
230 : 0b 011 100 110 : Digital padlock
- Author: Jean THOMAS
- Description: A 4-digit electronic padlock
- GitHub repository
- Wokwi project
- Extra docs
- Clock: 100 Hz
- External hardware: Four push buttons, cabled as active high with hardware debounce circuitry.
How it works
Each buttons press is detected by a rising edge detector, and each button press is decoded into a binary code. That binary code is stored in a shift-register which is continuously checked against a reference value (’the padlock code’).
How to test
Connect a clock generator to the clock input, connect all four buttons with a debounce circuit - the buttons should act as active high.
IO
| # | Input | Output |
|---|---|---|
| 0 | clock | none |
| 1 | Button A | none |
| 2 | Button B | none |
| 3 | Button C | none |
| 4 | Button D | none |
| 5 | none | none |
| 6 | none | Button press detected |
| 7 | none | Code valid |