# wiegand Module | Since | Origin / Contributor | Maintainer | Source | | :----- | :-------------------- | :---------- | :------ | | 2020-07-08 | [Cody Cutrer](https://github.com/ccutrer) | [Cody Cutrer](https://github.com/ccutrer) | [wiegand.c](../../app/modules/wiegand.c)| This module can read the input from RFID/keypad readers that support Wiegand outputs. 4 (keypress) and 26 (Wiegand standard) bit formats are supported. Wiegand requires three connections - two GPIOs connected to D0 and D1 datalines, and a ground connection. ## wiegand.create() Creates a dynamic wiegand object that receives a callback when data is received. Initialize the nodemcu to talk to a Wiegand keypad #### Syntax `wiegand.create(pinD0, pinD1, callback)` #### Parameters - `pinD0` This is a GPIO number (excluding 0) and connects to the D0 data line - `pinD1` This is a GPIO number (excluding 0) and connects to the D1 data line - `callback` This is a function that will invoked when a full card or keypress is read. The callback will be invoked with two arguments when a card is received. The first argument is the received code, the second is the number of bits in the format (4, 26). For 4-bit format, it's just an integer of the key they pressed; * is 10, and # is 11. For 26-bit format, it's the raw code. If you want to separate it into site codes and card numbers, you'll need to do the arithmetic yourself (top 8 bits are site code; bottom 16 are card numbers). #### Returns `wiegand` object. If the arguments are in error, or the operation cannot be completed, then an error is thrown. #### Example local w = wiegand.create(1, 2, function (card, bits) print("Card=" .. card .. " bits=" .. bits) end) w:close() # Wiegand Object Methods ## wiegandobj:close() Releases the resources associated with the card reader. #### Syntax `wiegandobj:close()` #### Example wiegandobj:close()