The zigbee spec is freely available, I fail to see how BLE would be any more "open source".
I think it's just that every smartphone, tablet, laptop, etc now has BLE integrated, so it's easy to make a widget like a soil moisture sensor and connect it to your phone. Also, the newer LE version of bluetooth is quite power efficient so it can run for a while on a CR2032 if you take care to put the MCU in sleep mode between measurements, and whatnot.
Comments
The zigbee spec is freely available, I fail to see how BLE would be any more "open source".
I think it's just that every smartphone, tablet, laptop, etc now has BLE integrated, so it's easy to make a widget like a soil moisture sensor and connect it to your phone. Also, the newer LE version of bluetooth is quite power efficient so it can run for a while on a CR2032 if you take care to put the MCU in sleep mode between measurements, and whatnot.