Reference Design Silicon Labs ENERGY-HARVEST-RD
Energy Harvesting with Wireless Sensor Node
Detailed Description
The Energy Harvesting Reference Design illustrates how to use an Si1xxx wireless microcontroller in an extremely low power wireless sensor node application.
Wireless Sensor Node for Energy Harvesting
The wireless sensor node is powered by a solar cell array.
The power that is produced by solar energy is stored in a thin film battery. The wireless MCU measures temperature, charge level on the thin battery and light level. This data is then sent wirelessly to a USB adapter that is connected to a PC. The PC runs a GUI that displays the information graphically.
The Sensor Node operates at 919.84 MHz and is powered by a solar energy harvesting power supply. When the wireless Sensor Node is not transmitting data, the Si1012 wireless MCU can remain in a low-power state where it only consumes 50 nA. The leakage current of the energy harvesting supply, when enabled, is approximately 3 µA and is cancelled out by as little as 50 lux shining into the solar cell. This allows the energy harvesting supply to power the system for approximately 7 days in a dark closet (in the ON position) or indefinitely if there is a periodic light source that replenishes the lost energy. The system works both in indoor lighting (200 lx) and outdoor lighting (10,000 lx) conditions.
The Si1012 Wireless MCU is used for the sensing and RF transmission functions of this reference design. In sleep mode, the Si1012 supply current is approximately 50 nA. When the MCU is awoken from sleep mode using the push button switch, it samples the current temperature using the on-chip temperature sensor, the remaining charge in the thin film battery, and the amount of ambient light at the solar cell. The temperature and remaining charge are transmitted over the RF connection once per button press. The light level is transmitted once a second for three minutes.
Energy Harvesting Reference Design Software
The ENERGY-HARVEST-RD reference design includes software that is loaded on PC to display the quantities that are measured by the microcontroller in the wireless sensor node:
- Temperature (measured from the on-chip temperature sensor on the MCU)
- Light level (measured from the voltage across the solar array)
- Charge level (the amount of charge remaining in the battery)
Kit Contents
- Si1012 Energy Harvesting Wireless Sensor Node
- EZRadioPRO USB Dongle
- ToolStick Base Adapter
- 3-foot USB extension cable
Energy Harvesting Reference Design Schematic Diagram
Other Names:
ENERGYHARVESTRD, ENERGY HARVEST RD
