TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: In manufacturing a sensor device (100; 200; 300; 400), the electronic circuitry (22) and the thermal sensor portion (21) are manufactured in the same functional layer (20). The electronic circuitry (22) and the thermal sensor portion (21) are manufactured with the same processing steps. The second functional layer (30) comprises a void (31) aligned with the thermal sensor portion (21), and/or where the third functional layer (40) comprises a void (41) aligned with the thermal sensor portion (21). The manufacturing process for manufacturing the second functional layer (30) is executed at a relatively low temperature, preferably less than 400 degrees C, so that the components in the first functional layer (20) are not affected by this manufacturing process. The third processing stage is performed following the second processing stage. The manufacturing process for manufacturing the third functional layer (40) is executed at a temperature lower than the temperature of the manufacturing process for manufacturing the second functional layer (30), preferably less than 300 degrees C, so that the components in the second functional layer (30) are not affected by this manufacturing process. The second functional layer (30) with battery and antenna is manufactured on the first functional layer (20), and where the third functional layer (40) with solar cell(s) is manufactured on the second functional layer (30). The second functional layer (30) with battery and antenna is manufactured on the first functional layer (20), and where the third functional layer (40) with solar cell(s) is manufactured on the second (12) of the main surfaces. The second functional layer (30) with battery and antenna is manufactured on the second (12) of the main surfaces, and where the third functional layer (40) with solar cell(s) is manufactured on the first functional layer (20). The third functional layer (40) with solar cell(s) is manufactured as outermost layer, and where a carrier plate (50) is arranged on top of this third functional layer, the carrier plate preferably being made from glass or polyimide. Preferred Device: In the sensor device, the thermal sensor (23) comprises a thin central body (610) and thermocouples (500) arranged along the edges of the central body (610); where the central body (610) is designed to be heat-absorbing; where all thermocouples are electrically connected in series while thermally being connected in parallel; and where the central body (610) and the thermocouples (500) are implemented as patterns in silicon. The thermal sensor (23) comprises four individual sensor portions (700), each sensor portion (700) comprising a thin central longitudinal body (710) and thermocouples (500) arranged along the opposing longitudinal edges of the central body (710). The thermal sensor (23) comprises a thin central longitudinal body (810) and thermocouples (500) arranged along the opposing longitudinal edges of the central body (810), with terminals (801) contacting the end thermocouples and also terminals (801) contacting at intermediate thermocouples, so that sensor signals can be obtained from different portions of the sensor.