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Sensors Expo 2018: Solar Power for Indoor Sensor Systems

It seems that everywhere you go these days people are talking about IoT. Whether it’s smart light bulbs that respond to your voice or sensors that transmit data, these devices are everywhere. While IoT growth is staggering it will undoubtedly run into some future issues.

One of the major barriers to mass deployment of wireless IoT sensors is battery lifetime. Depending on power requirements, a primary battery will last a few months to a few years.  Short battery life adds significant cost to a system over its lifetime. The batteries themselves may be inexpensive, but labor and repeated replacements can add significant costs over a product’s lifecycle.

For example, a Bluetooth light/temperature sensor for HVAC/occupancy monitoring that sends data about once per second will consume about 1.5 mWh of power each day. If a common CR2032 battery (225 mAh, 675 mWh) is used to power the system, then the system will operate for about 14 months. This assumes that the battery will supply the full rated capacity, which will probably not be the case since the battery is rated at a 0.2 mA continuous discharge and the peak radio transmit current is over 10 mA.

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