A sensor data transmission system includes a central processor, first and second sensor assemblies, and first and second conductors. The sensor assemblies each include a sensor, a processor and a relay. The sensor is configured to detect a condition. The processor is configured to receive a condition detected signal from the sensor and open the respective relay at least once indicative of the condition and within a pre-determined time interval. The first conductor is electrically in contact with the processors of the first and second sensor assemblies and is interposed by the relay of the second sensor assembly. The second conductor is electrically in contact with the central processor and the processor of the first sensor assembly and is interposed by the relay of the first sensor assembly.