  Understanding the transport characteristics at the atomic limit is the
prerequisite for futuristic nano-electronic applications. Among various
experimental procedures, mechanically controllable break junction (MCBJ) is one
of the well adopted experimental technique to study and control the atomic or
molecular scale devices. Here, we present the details of the development of a
piezo controlled table top MCBJ set up, working at ambient condition, along
with necessary data acquisition technique and analysis of the data. We
performed conductance experiment on a macroscopic gold wire, which exhibits
quantized conductance plateau upon pulling the wire with the piezo. Conductance
peak up to $\sim 20 G_0$ ($G_0 = 2e^2/h$, $e$ being the electronic charge and
$h$ being the plank's constant) could be resolved at room temperature. A
well-known test bed molecule,$4, 4^\prime$ bipyridine, was introduced between
the gold electrodes and conductance histogram exhibits two distinctive
conductance peaks, confirming the formation of single molecular junction, in
line with the previous reports. This demonstrate that our custom-designed MCBJ
set up is capable of measuring quantum transport of a single molecular junction
at ambient condition.
