This is a great project but I need some help with the power supply. I have used the same Adafruit fingerprint sensor and a solenoid to open the lock.

The fingerprint sensor works fine to switch on LEDs when the correct fingerprint is detected.

I can easily open the solenoid straight from the Arduino (with or without the relay) provided the fingerprint sensor is not connected.

So, there does not seem to be enough power to power open a 5v solenoid (motor) and to run the fingerprint sensor at the same time, even when I connect a 5V relay and try to open the solenoid from a separate power source. The signal from the pin13 is just to small to switch the relay. Does anyone have any suggestions. I am not sure why such a tiny voltage is sent to the OUTPUT on detection of the correct fingerprint.

Perhaps I do not understand the total power output of the Arduino well enough. I am running the Arduino off a 9V battery.

Please can someone advise what to do.