The linear-to-rotary actuator includes an elongated drive member constrained to linear movement, and a rotary member constrained to rotary movement. The elongated drive member has a coupling end and an engaging member that projects from the coupling end. The rotary member has a track defining an Archimedean spiral. The track is adapted to receive the engaging member. The engaging member is constrained to slide in the track such that linear movement of the elongated member effects rotation of the rotary member. The track may be a slot, a groove, or other guide. Alternatively, instead of a track defined directly in the rotary member, the actuator may include a linking member (such as a disk or rectangular bracket) attached to the rotary member, the linking member having a track defining an Archimedean spiral defined therein, the engaging member being slidable in the track to convert linear motion into rotary motion.