18B20 Waterproof temperature sensor
Price in Sri Lanka

This is a 1 Meter Long Waterproof, sealed and pre-wired digital temperature sensor probe based on DS18B20 sensor. It is very handy for when you need to measure something far away, or in wet conditions. Because they are digital, you don’t get any signal degradation even over long distance.

These 1-wire digital temperature sensors are fairly precise (±0.5°C over much of the range) and can give up to 12 bits of precision from the onboard digital-to-analog converter. They work great with any microcontroller using a single digital pin, and you can even connect multiple ones to the same pin, each one has a unique 64-bit ID burned in at the factory to differentiate them. Usable with 3.0-5.0V systems.

The only downside is they use the Dallas 1-Wire protocol, which is somewhat complex, and requires a bunch of code to parse out the communication. When using with microcontroller put a 4.7k resistor to sensing pin, which is required as a pullup from the DATA to VCC line.

Cable specs:-

• Stainless steel tube 6mm diameter by 30mm long
• Cable is 36″ long / 91cm, 4mm diameter (1 Meter Long)
• Contains DS18B20 temperature sensor
• Three wires – Red connects to 3-5V, Black connects to ground and White is data.

DS18B20 Sensor Technical specs:-

• Usable temperature range: -55 to 125°C (-67°F to +257°F)
• 9 to 12 bit selectable resolution
• Uses 1-Wire interface- requires only one digital pin for communication
• Unique 64 bit ID burned into chip
• Multiple sensors can share one pin
• ±0.5°C Accuracy from -10°C to +85°C
• Temperature-limit alarm system
• Query time is less than 750ms
• Usable with 3.0V to 5.5V power/data