Generic R503 DC12V Low Power Consumption Ring Fingerprint Access Control Board - STM8 Processor

The R503 board is designed to operate from a 10 to 24 Volt DC power supply. This wide range allows it to be powered by common 12V security system power adapters or directly from a 24V industrial DC bus. Ensure your power source can provide stable voltage within this range for reliable operation.

To enroll a fingerprint, apply power and long-press the SET button for 3-4 seconds until the blue LED blinks. Place the finger to be registered on the optical sensor and wait for five audible beeps before removing it. The module can store multiple fingerprints; you can add more during the enrollment period before the LED stops blinking and the module returns to verification mode.

Yes, the relay activation duration is fully adjustable from 0.5 seconds to 13 seconds. Use a small screwdriver to turn the onboard multiturn potentiometer clockwise to increase the time or counterclockwise to decrease it. This allows you to tailor the pulse length for different locks or mechanisms.

No, the R503 is a standalone control board. The integrated STM8 microcontroller handles all fingerprint processing, enrollment, verification, and relay control internally. You only need to provide DC power, connect the relay output to your lock or device, and use the onboard button and sensor for operation.