Template:UART-Fingerprint-Reader-FAQ

Question: Why is there no data returned from the fingerprint reader?

Answer: In normal operation, the module would echo corresponding characters after receiving a valid command. Here are some notices: The module may make a sound “beep” after powered up, indicating it is working well. The users can build communication between the module and the PC via a USB-to-UART interface. It is recommended to use the matching USB-to-UART module provided by Waveshare. For more information, please visit: CP2102_USB_UART_Board_(type_A) and PL2303_USB_UART_Board_(type_A) Select a appropriate Baud rate (Default: 19200) The serial ports should be in common-ground connection.

Question: What is the MINI USB interface on the fingerprint reader used for?

Answer: This MINI USB interface is used for firmware upgrading, but not power supply. In normal operation, this interface should be keep unconnected.

Question: What is the pin BL on the fingerprint reader used for?

Answer: The pin BL is used for controlling the backlight on the fingerprint collector and reading the backlight state. In most applications, this pin can be unconnected, since the module can control the backlight automatically itself and the external system does not need to control this pin.

Question: The system shows that the new fingerprint has been added successfully, but the fingerprint matching for the new fingerprint is failure, and no new user is added. How to deal with it?

Answer: In the test, you should deselect the option upload eigenvalue. Because the eigenvalue(s) will be uploaded to the PC but not written into the fingerprint reader, if the option upload eigenvalue is selected.