The pyroelectrical response of infrared sensor dodycylbenzene sulfonic acid (DBSA) doped polyaniline (PANI) and polyvinylidene fluoride (PVDF) blend films was reported in this work. Modulation frequency dependence of the pyroelectric response of PANIDBSA/PVDF blend films with different weight percentages (0, 10, and 20) of PANI has been investigated using the proposed an electrical chopped circuit. The electrical chopped circuit is composed of computerized Arduino board to generate the chopped frequency and shielded with the transmitting circuit, infrared sensor blend film, and the amplification circuit. The PANI-DBSA/PVDF blend film with 10 wt.% of PANI showed the optimum the pyroelectric response. The voltage responsivity (Rv) of PANIDBSA/PVDF with 10 wt.% of PANI was 158 V/W at 0.2 Hz and the noise equivalent power (NEP) of was 2.8×10-7 W/Hz1/2 at 100 Hz. The results indicated that the PANIDBSA/PVDF blend film with 10 wt.% of PANI are suitable as an active material for pyroelectric infrared sensor.