Micro-solid oxide fuel cells (SOFC) sensors prepared via depositing a thin film BYCF (10 wt% [Ba0.95FeY0.05O2.8] + 90 wt% [Co2O3]) – GDC20 (Gd0.20Ce0.80O1.95) cathode and NiO-GDC20 (Gd0.20Ce0.80O1.95) anode on a GDC20 electrolyte layer were operated at 800 °C. The structure, which receives only biogas, was formed into 15-mm pellets with only one side for detecting methane (CH4). The detection of 40% to 99.99% CH4 provided a high level of accuracy compared with 10% to 30% CH4. The biogas (60% CH4) from the Oil Palm Industry and Rubber Cooperative Fund, Thailand, increased remarkably at voltage levels of 20 to 21 mV. The electrical signal from the micro-SOFC sensor corresponded to the quantity of CH4, with the chemical reaction of the dry reforming activities (NiO and Co3O4) highly catalyzed and transformed from CH4 to H2, thus generating electrons. It was concluded that the micro-SOFC sensor is suitable for detecting methane measurements at intermediate temperatures, with the ceramic structure offering low degradation compared with metal sensors.