From Apple Watch, BlueTooth is connected to TI SensorTag CC 2650 to acquire sensor information.
After installation, iPhone is unnecessary, and communicate directly between Watch and SensorTag.
The sensor type is
1. Ambience temperature in ° C/° F
2. Object temperature in ° C/° F
3. Humidity in % RH
4. Barometer in hPa
5. Illuminance in Lux
You can select.
Sensor update interval 1 sec
Once you setup complication, you can start it immediately.

For the operation of this software,
AppleWatch Series 3 Watch OS 4
TI SensorTag CC 2650 is required.