  We introduce a systematic method to spectrally design quasi-one-dimensional
crystal models described by the Dirac equation in the low-energy regime. The
method is based on the supersymmetric transformation applied to an initially
known pseudo-spin-1/2 model. This allows extending the corresponding susy
partner so that the new model describes a pseudo-spin-1 system. The spectral
design allows the introduction of a flat-band and discrete energies at will
into the new model. The results are illustrated in two examples where the
Su-Schriefer-Heeger chain is locally converted into a stub lattice.
