Batteryless sensing utilizing ambient lighting at Lapland UAS

For over three months, an ambient light-based energy harvesting (EH) system has been operating at Lapland UAS. This setup uses an EH solution developed by Epishine to power a low-power Bluetooth Low Energy sensor—specifically, a RuuviTag developed by Ruuvi. The system draws energy from both indoor office lighting and natural outdoor light.

The graph shows the system's voltage over time. Gaps in the data indicate periods when the device ran out of power, typically during the night. As ambient light has increased over time, these gaps have become shorter, showing that daylight hours are getting longer here in the North. For instance, in February, the system stayed online for about 12 hours each day using only outdoor ambient light. By early May, it was running for up to 22 hours daily under the same conditions.

The sensor takes measurements every few seconds and sends them to a Ruuvi Gateway, which forwards the data every minute. These measurements include ambient air pressure, relative humidity, temperature, data from a 3-axis accelerometer, and the sensor's battery voltage.

The system is enclosed in a 3D printed enclosure for some added protection. The RuuviTag is placed at the back of the case, while the Epishine EH solution is housed above.