Hold the DS18B20 Digital Temperature Sensor with the 3.5mm Audio Jack Sleeve as the direction showed on the pic.

The circuit connection shows on the up pic,the 4k7~10k pull up resistor is optional.

Band the first leg of DS18b20 up to the sleeve as GND pin.

band the middle pin and plug it to the middle pad of audio jack.

Cut the third pin short and plug it to the short&middle hole of the audio jack. 

Solder all 3 pins like as shown on the pic.

Pull up resistor is optional,if need,u can solder an 4k7~10k resisitor between VCC pin and DATA pin.

Plug the PVC tube on.

Done!