A fingerprint activated doorlock that maintains key functionality (basically unlock door with finger but key still works if power goes out).
Prototyped with Shiv G. in Fall 2021 ECE 120 Honors lab.
v1.0 Apparently fingerprint sensor doesn't like 5V, it needs 3.3V. I read the documentation for the wrong sensor. Need 3.3V reg and decoupling caps for motor.
v1.1 Added the 3.3V regulator, decoupling caps, seperated logic power from servo power with diode. Added test points and pin 13 led to help with debugging.
Used a gear with an hourglass cutout to drive the lock spindle. The hourglass cutout gives the spindle enough space to lock and unlock using the key without hitting the gear. However, if driven past the clearance, the gear will still rotate the spindle.