Introduction
The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. In addition, the DS18B20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply. Datasheet.
KY-001
I got a KY-001 Arduino Temperature Module or here as part of a kit with 40 modules. The youtube video KY-001 Temperature sensor DS18B20 Arduino introduces both the breakout board (from Keyes) and the component. The KY-001 board include a pull-up resistor of 4.7 kOhm that is required for generating the correct data signal.
Waterproof and cabled
Several different online shops sell the DS18B20 temperature sensor encased in watertight metal and with a waterproof cable. I got mine form pchbutik.se. Most of these modules do not contain the 4.7 kOhm pull up resistor. Thus you must include that in the wiring, explained in the project page for the DS18B20 sensor.
