Hi,
I need a temperature reading within a small range (35-40°C). The most important aspect of this project is to log the relative changes. The absolute temperature is not very important (e.g. it is not important whether the temperature is 37 or 37.4, it is important whether the temperature increases or decreases by 0.1°C).
Can anybody give me an advice what kind of sensor I need?
thanks
lightbulb82
Check the DS18B20, a digital sensor that can operate in 12 bit with a resolution of 1/16 degree C. There is an excellent library for it - MilesBurton.com - with plenty of examples. The datasheet can be found at - http://pdfserv.maxim-ic.com/en/ds/DS18B20.pdf
Hi,
this was one of the sensors I already considered. The data sheet gives an accuracy of +/-0.5. I think this relates to the absolute temperature. However, I have no clue what accuracy this sensor has regarding his relative temperature. Has anybody tested this?
My other option would be the LM35.
cheers
lightbulb82
The DS18B20 DOES offer the high resolution you want...
If you can figure out how to make it do so!! Not trivial. Not impossible.
I don't know the library cited... it may make the above easy.
DS18B20 way to go because the LM35 is an analog device, with all of the weaknesses thereof, especially when you want such high resolution.
Yes... I THINK the 0.5 you saw was about how close the REPORTED tture will be to the actual tture. For what you want... which, thank you, you made very clear, the DS18B20 will be good.
Buying one or two is always a pain. Expect to pay "hefty" p&p... but you do have to make it worth the retailler's time, don't you? In the UK...
In the US...
They are also often for sale on eBay in small batches.
Be sure you are buying the DS18B20.... the "B" is important. Also, you don't want the DS18B22
try SE95 its i2c bus( very simple to use) got 13bit resolution (0.03125C)
its accuracy is +-1c from 0C to 100C
Hi,
thanks a lot. I think my next step is to order the DS18B20. I will keep you informed about the status.
thanks
lightbulb82