CMM2: DS18B20 Temp sensor problem

Author	Message
Paul_L Guru Joined: 03/03/2016 Location: United States Posts: 769	Posted: 02:40am 14 Aug 2020         lizby said     bigmik said   What is the zero degrees issue? Paul_L once suggested to me that a very good way of testing/comparing perhaps dodgy waterproof DS18B20s was to put crushed ice in a glass, pour in a modest amount of chilled water, wait a few minutes for the ice to bring the water to very close to freezing, and insert the probes. That should be very close to 0C if you have the mix right, and a well-established universal calibration point. Funny thing about standards -- most of them aren't standardized -- except for the ice point of water. It works best if you use distilled water (filtered rain water?), use an insulated coffee mug, ice chips not big ice cubes, stir the ice water for 30 seconds before inserting the probe, and insert the probe in the center of the mug without touching the sides or bottom. You should be able to achieve within 0.2°C of a true 0°C easily. Paul in NY