3.CPU and RF Layer: The CPU and RF layer hosts the local ARM Cortex M3 microcontroller unit (MCU)
EFM32G230F128, as well as the Bluetooth Low Energy (BLE) transceiver (Tx/Rx) nRF8001. This is
considered the core layer, which cannot be replaced.
4) Harvesting Layer: The energy harvesting layer is responsible for scavenging ambient energy from the
environment and converting it into usable electrical energy. Multiple energy harvesting sources can be
utilized such as wireless power transfer (WPT), which is also used for remote wakeups, and vibration energy
harvesting (VEH) [5].
5) Custom Layer: an application dependent custom layer can be added as necessary. This will allow
customization to be packaged inside the rugged housing. Most customizations can also be accomplished
using attachable modules
6) Backup Battery: In some situations, energy harvesting might be scarce, unavailable, or excessively abundant.
Having a backup battery allows the platform to run exclusively from the battery when energy harvesting is
low, or recharge a small coin battery, such as ML-2020, when excessive energy is available.
7) Patch Antenna: the antenna is an important part of the platform. Sprouts utilizes a flat patch antenna, seen in
Figure 1 D, which also serves as a cover for the metallic package. The unique advantage of patch antennas is
the bottom ground layer which allows the platform to be mounted on metal without effecting reception. In
addition, patch antennas are flat and do not exhibit any mechanical moving parts making them better suited
for harsh industrial environments.
8) Packaging: Sprouts uses a cylindrical aluminum, copper, or steel packaging 23mm in diameter and only
10mm in height, allowing the package to be light and robust.