Keypad mounted in keypad module box
Closeup of the keypad component installed in the keypad module.

This module uses an AVR microcontroller to interface a cheap numeric keypad. The PIN code is set by the user and stored in EEPROM. If entered correctly; a one second pulse is sent on either output 1 or 2, depending on the selected mode. A tamper pin will be shorted to 0V when the module is connected. This keypad module is not itself meant to control anything, but it provides trigger signals for other control modules to act upon. It has three LEDs (green, red and alarm) which can be used to convey messages from that other control module. Powered by: 5V.

Table of content



Mode 1

To activate mode 1 enter PIN + * (star), a one second green light indicates correct PIN and confirms command.

Mode 2

To activate mode 2 enter PIN + # (number sign), a two seconds green light indicates correct PIN and confirms command.

PIN code

Change PIN

To change PIN enter current PIN + 0 (zero), a yellow light indicates that a new PIN can be entered. The new PIN is entered and confirmed with #, a green light indicates a successful change. Any button other than # will reject the new code and keep the old one, a red light indicates this.

Wrong PIN

When the wrong PIN is entered you get a red light. If the wrong PIN is entered three times the panel will not be usable for one minute. The red light will flash during this period.



  1. PD2 Keypad R1
  2. PD3 Keypad R2
  3. PD4 Keypad R3
  4. PD5 Keypad R4


  1. PB0 Keypad K1
  2. PB1 Keypad K2
  3. PB2 Keypad K3
  4. PB3 Mode 1 signal
  5. PB4 Mode 2 signal
  6. PB5 Green LED indicator
  7. PB6 Red LED indicator
  8. PB7 Heartbeat signal

D-Sub 9-pin

  1. 5V
  2. 0V
  3. Mode 1 signal
  4. Mode 2 signal
  5. Tamper N.C (short to 0V)
  6. Heartbeat signal
  7. Alarm LED from other controller
  8. Green LED from other controller
  9. Red LED from other controller


Keypad internal connections and dimensions
Showing the internal connections and dimensions for a keypad.
  1. n/a
  2. K3
  3. K2
  4. K1
  5. R1
  6. R2
  7. R3
  8. R4

Schematic drawing

Security keypad circuit
Schematic drawing for the security keypad module; with AVR ATtiny2313.

Source code


Keypad with programmable PIN code, written with BASCOM-AVR.

Master Releases

0 0 0 v1.0 Visual Basic 5 months ago

Image gallery

Parts list

Project: Security keypad with programmable PIN by Thomas Jensen is licensed under CC BY-SA 4.0 with attribution required.

Similar resources

  •   Created Nov 16, 2007
  •   Last modified 5 days ago
  • Project status: Completed