Electronic code lock with the ability to rewrite the entry code. Usind Arduino Uno or Nano, OLED 128x64, I2C, SSD1306 driver and matrix 3x4 keypad. Can be used for entrance door, car door or a locker. Any number (0-9) can be used. Pressing the right code activates the relay for 2 seconds. To change the 4 digits code press 'Change Code' pushbutton and key 4 new numbers. The pushbutton has to be mounted in an area not accessible to the public. The 4 digits are stored in the chip's EEPROM, so the numbers are retained when the power is off.
The codelock can be used without the OLED. Ready LED is used instead of the OLED screen.