STM350U

STM350U is a dolphin temperature and humidity sensor module. This module that enables the realization of energy harvesting temperature and humidity sensors that communicate wirelessly using the EnOcean radio standard. STM 350 modules wake up at a rate of approx. once every 100 seconds to read the status of the integrated temperature and humidity sensor. If there is a significant change in measured temperature or humidity versus the last reported values then a radio telegram will be transmitted immediately. In case of no relevant change, a redundant retransmission signal (heartbeat) is sent after 15 minutes to announce the current values. Power is provided to STM 350 by means of a small pre-installed solar cell which works in conjunction with an integrated energy storage element in order to ensure operation in periods without ambient light. STM 350 additionally provides the option to connect an external 3 V backup battery to enable operation with little or no available light.

• 50 ohm helix antenna (on-board) antenna
• 902.875MHz ASK radio frequency and 125Kbps data rate
• Radiated output power (typ.) is +5dBm
• Operation time in darkness at 25°C is min. 10 days, if energy storage fully charged
• Sensor performance: temperature: ±0.5K across entire range, humidity: ±3% R.H.. between 20 to 80% R.H.
• Measurement interval is approximately once every 100s
• Transmission interval: every 7 to 14 measurements (affected at random)
• EEP: A5-04-03, SIGNAL 0x06 (energy level reporting), SIGNAL 0x0E (entering transport mode)
• Operating temperature range from -20°C to +60°C (absolute maximum)
• Operating and storage humidity: max: 0% to 93% R.H.., non-condensing