Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

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#78025 Good morning Today I received the "rfid 7941E v.3" reading module from aliexpress. The reader reads em4100 tag at 125khz. I do not have much experience and I would like to ask you some connection ideas with arduino or esp8266. Can you help me? thank you
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By QuickFix
#78073 I'm not sure about this one (I've got different boards), but if it also is just emitting the RFID keyfob numbers in a RS-232 formatted serial way, you can just connect it to the RX (GPIO3) of the ESP (don't forget to include a level-shifter if needed) and read the data as is.

Of course you need to make the connection removable so you can (re-) flash the ESP as needed.

As I understand, this board outputs Wiegand (so not only the serial of the fob in plain format) in the following format:
  • Data Head = 0x02 (fixed byte)
  • Length = 0x0A (total length of the packet is 10 bytes for 125kHz fobs)
  • Card Type = 0x02 (EM4100 = 125kHz chips)
  • Card Serial = SN0~SN4 (5 bytes)
  • BCC Check = XOR Check (Except Data Head And Data End)
  • Data End = 0x03 (fixed byte)