  A single nitrogen-vacancy (NV) center in diamond is a prime candidate for a
solid-state quantum magnetometer capable of detecting single nuclear spins with
prospective application to nuclear magnetic resonance (NMR) at the nanoscale.
Nonetheless, an NV magnetometer is still less accessible to many chemists and
biologists, as its experimental setup and operational principle are starkly
different from those of conventional NMR. Here, we design, construct, and
operate a compact tabletop-sized system for quantum sensing with a single NV
center, built primarily from commercially available optical components and
electronics. We show that our setup can implement state-of-the-art quantum
sensing protocols that enable the detection of single $^{13}$C nuclear spins in
diamond and the characterization of their interaction parameters, as well as
the detection of a small ensemble of proton nuclear spins on the diamond
surface. This article providing extensive discussions on the details of the
setup and the experimental procedures, our system will be reproducible by those
who have not worked on the NV centers previously.
