  It is shown that mean value of any observable with bounded spectrum can be
uniquely determined from binary statistics of the measurement performed on {\it
single} qubit ancilla coupled to a given system. The observable structure is
fully encoded in the corresponding POVM. The method is generalised to the case
of distant labs paradigm and discussed in the context of entanglement detection
with few local measurements. The results are also discussed in the context of
quantum programming.
