  Detecting compact objects by means of their gravitational lensing effect on
an observed companion in a binary system has already been suggested almost four
decades ago. However, these predictions were made even before the first
observations of gravitational lensing, whereas nowadays gravitational
microlensing surveys towards the Galactic bulge yield almost 1000 events per
year where one star magnifies the light of a more distant one. With a specific
view on those experiments, we therefore carry out simulations to assess the
prospects for detection of the transient periodic magnification of the
companion star, which lasts typically only a few hours binaries involving a
main-sequence star. We find that detectability is given by the achievability of
dense monitoring with the required photometric accuracy. In sharp contrast to
earlier expectations by other authors, we find that main-sequence stars are not
substantially less favourable targets to observe this effect than white dwarfs.
The requirement of an almost edge-on orbit leads to a probability of the order
of $3 \times 10^{-4}$ for spotting the signature of an existing compact object
in a binary system with this technique. Assuming an abundance of such systems
about 0.4 per cent, a high-cadence monitoring every 15~min with 5 per cent
photometric accuracy would deliver a signal rate per target star of $\gamma
\sim 4 \times 10^{-7}~\mbox{yr}^{-1}$ at a recurrence period of about 6 months.
With microlensing surveys having demonstrated the capability to monitor about
$2 \times 10^{8}$ stars, one is therefore provided with the chance to detect
roughly semi-annually recurring self-lensing signals from several compact
compacts in a binary system. If the photometric accuracy was pushed down to 0.3
per cent, 10 times as many signals would become detectable.
