A Bluetooth Module Maker based on Nordic nRF53 & nRF52 Solution (nRF5340 nRF52840 nRF52833 nRF52832 nRF52820 nRF52810 nRF52811 nRF52805), Bluetooth Specification Version: BT5.2 & BT5.1 & BT5 & BT4.2
https://devzone.nordicsemi.com/f/nordic-q-a/16133/nrf51822---poor-rf-performance-on-custom-pcb
https://raytac.blog/tag/iot/
https://www.minew.com/bluetooth-module/?gclid=Cj0KCQjwz8emBhDrARIsANNJjS5pqebdqT4dV0eSQ91Wch2oww4DWVq2bkihAA540Pwqubzq3rmmEjYaAirgEALw_wcB
https://www.renesas.com/us/en/application/key-technology/bluetooth-low-energy
https://predictabledesigns.com/review-of-bluetooth-low-energy-ble-solutions/
https://developex.com/blog/best-modules-shields-and-boards-for-ble-usage-on-arduino/
https://en.wikipedia.org/wiki/Bluetooth_Low_Energy
https://punchthrough.com/android-ble-guide/