Hi, A short and long explanation to start with:
<short>I have 2 ds18b20 sensors connected to 2 diferent pieces of hardware</short>
<long>I have already for quite some time a ds18b20 temp sensor directly connected to my pimatic-RPi.
3 days ago I put a minorly modified rfbox-ds18b20.ino sketch (from here or here) in an arduino and connected a ds18b20 sensor and put it on a 5V feed. I want to modifiy this one and use one of the 2 popular low-power libs to run it on batteries.
Just out of curiosity I put the sensors next to each other about 0.5 cm apart.
There is a constant difference of 0.6 to 0.64 degrees between the two sensors. Based on the specs the accuracy is ±0.5°C from -10°C to +85°C, so completely in range and completely according specs.
Nevertheless it bothers me that they do not give the exact same value and I’m tempting to calibrate them (lots about that on the web).
But my real questions are:
- Do you guys/girls calibrate your ds18b20 or dht21/22 sensors?
- If you reconnect them, or change something in the hardware setting (for example the resistor or other wiring) do you (need to) recalibrate?