After having had continuous and numerous problems with end devices compatible with Home Assistant, I decided to create these devices from scratch, in order to have total control over them. I then created a radio to MQTT bridge that makes use of a NodeMCU (ESP8266) Wi-Fi module [NodeMCU - Wikipedia] with a NRF24L01 + module [https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf]. I also created door sensors and vibrations sensors with a PIC16LF1829 chip + NRF24L01+ (used as radio transmitter).
Unfortunately the Microchip licenses do not allow me to publish the sensor project on the PicMicro with an open source license (such as MIT, GPL etc.); however I am happy to publish at least the bridge, which is universally compatible with any transmitter based on NRF24L01+. In addition, with a few code changes you can make the bridge work with another radio module (let me know if it might be useful to add changes to the code).
As you will experience, it is very easy to build this device. Just connect a NodeMCU to a NRF24L01+ module and install my firmware. There is no need for anything else. I would be happy if someone contributed to the project by creating very low consumption end devices with mcus (connected to NRF24L01 + modules) that are compatible with open source licenses. Any feedback is really welcome, and I hope this project grows and becomes more and more useful to the Home Assistant community.