https://www.youtube.com/watch?v=WA6GCwnS570

Version 1:
code (3dataSendingToClock) for BMP280, DS18B20, si7021
Depending on pcb wiring, works in 5V or 3v3
This version mounted in 5v, 16Mhz internal, powered by a small solar panel. Transmits every 40 seconds

version2:
code (nrf North) for ds18b20 in sleep Mode
3v3 wiring
Wakes up Transmits every 4 minutes and falls asleep again
On niMh battery in 3v3. Q external 8Mhz