Microduino NFC Unlocks Computer
|Language:||English • 中文|
This system uses Microduino nRF24 module to set up network. The master system use the Microduino core module (Microduino-Core or Microduino Core+ or Microduino 32U4), Microduino nRF24, Microduino NFC, Microduino FT232R which build a gateway. Using the Miccroduino-Core, Microduino nRF24 and AVR-USB-HID made by yourself to build a network point. Every electronic tag has different ID, the gateway identifies different ID, then sends the command to it, otherwise waiting for electronic tag. After the network point received the command, trigger the AVR-USE-HID device to input the passward (actually simulate the keyboard to input the keyboard value), then unlock the computer immediately.
Bill of Materials
Microduino network point
Download UsbKeyboard library：https://github.com/suapapa/arduino_library_UsbKeyboard
Download RF24 library: https://github.com/maniacbug/RF24/
Download NFC library: https://github.com/adafruit/Adafruit_NFCShield_I2C
The voltage of AVR-USB-HID device must be in 2.8v to 3.6V. We will introduce one method which changed the Microduino power supply to 3.3v. You can change the power selection resistor 0 to 3.3v pin, then the voltage will match the requirement. If you don't want to change the Microduino, there is another method which uses an external Voltage regulator tube, detailed information, please refer to following link: http://www.microduino.cc/wiki/index.php?title=Lesson_5--Microduino_Simulates_Computer_Keyboard
Principle introduction: 1.Two 68Ω resistor play a current-limiting resistance and protection function, to prevent accidental damage the computer USB port or microcontroller port. 2.The 2.2kΩ pull-up registor use to identify the bus state. If it connects to D+ and +5v, that means it is a high speed USB device, otherwise connects to D- and +5v, will be used as slow speed USB device. In this experiment, the keyboard's speed is slow, so it will connect to D-. 3.The 3.3V voltage chip use to power the system which leads to the Microduino core's I/O port voltage will be 3.3v, easy to identify the USB device.
We set up two points, so will define two points in gateway program, uses the "x" to select the point. If the player want to add more points, only need add more cases and the value of "x" in program.
Power on the gateway, and point connects to computer by the AVR-USB-HID device, and then use the NRF to identify electronic tag, check the notepad's value if match with the password. If yes, then you start to control.
Set up the system, the gateway read the electronic tag 1, then the point 1 will input the password automatically to unlock the computer. The same as point 2.
Pay attention issue