Wireless Module for Capacitive Soil Moisture Sensor v1.2.

Running on cr2450 battery (500mA).

Used the MySensors library

Operating mode - 8 mA Sleep mode - 2.2 microamperes

GitHub - https://github.com/smartboxchannel/EFEKTA_E73B_PWS_MODULE (links, gerber, cod, bom, foto)

Cost of the assembled device - $12

Video: