Guide by Tim; Fingerprint Scanner with Raspberry Pi Single Board Computer - Unlock with Biometrics!

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Hello Tim! I am getting these errors, could you help me out?

Hi Kou,

We’ll have to see your whole error stream to get a proper idea of what’s going on. You can access the forum via the web browser on your Pi, so could you copy the full message in between 3 backticks (`) into a post here?

That’ll help us troubleshoot this one :slight_smile:

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Hello James, here is the error

Traceback (most recent call last):
File “/home/kouma17/Adafruit_CircuitPython_Fingerprint/examples/”, line 22, in
finger = adafruit_fingerprint.Adafruit_Fingerprint(uart)
File “/usr/local/lib/python3.9/dist-packages/”, line 120, in init
if self.verify_password() != OK:
File “/usr/local/lib/python3.9/dist-packages/”, line 136, in verify_password
return self._get_packet(12)[0]
File “/usr/local/lib/python3.9/dist-packages/”, line 348, in _get_packet
raise RuntimeError(“Failed to read data from sensor”)
RuntimeError: Failed to read data from sensor

Hey Kou,

Seems that the Pi is having trouble communicating with the Fingerprint sensor. Try running:

ls /dev/tty*

You should see a list of available serial ports, including the one that the fingerprint sensor is connected to. If you do not see the sensor’s serial port, there may be an issue with the sensor or the connection.

If you can see it is recognised, ensure that the baud rate setting of the fingerprint sensor matches the baud rate setting of the uart object in your Python code. The default baud rate for the fingerprint sensor is 57600, but it can be changed using the set_baud_rate() method.


Hello sir,
i have a quick question about some parts
I’m using a capacitive fingerprint sensor and ttl usb adapter, and when i run the program, it doesn’t work.
Can i get a hint about what to change, please ?

My Error: AttributeError: module ‘adafruit_fingerprint’ has no attribute ‘Adafruit_Fingerprint’

This error can occur if you attempt to import the wrong file - Python does not distinguish between a script and a library module. What is the name of you script file?

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Hi Tim,

This is the error im facing.
And ttyS0 is listen in ls /dev/tty* command.
I don’t know how to set baud rate but im using default 57600 only.

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Hello, I have the same problem as Ali255702, do you have any idea what it could be?
I using and the fingerprint is ADA-751

It was a connection problem, use connecting pins or get the holes soldered

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