Temperature Sensor - choice / reliabilty

[LukeW]

One of the downsides of the DS18B20 is that it's pretty expensive, if you don't need the multi-drop 1-Wire bus and you're only working at approximately room temperature. A thermistor or bandgap sensor would be far cheaper.

[jdraughn]

I really like the MAX31725, +/- .5ºC accuracy from -40ºC to 105ºC, and .00390625ºC resolution. It uses I2C. $1.48 each in quantities of one from DigiKey. http://www.digikey.com/product-detail/en/MAX31725MTA%2B/MAX31725MTA%2B-ND/3737668

[oilburner]

cool chip, thanks jdraughn!

[nctnico]

For measuing temerature around the 25c mark, off board at about 2 mtrs and to a resolution of 0.1c ,  wondered what device the professional designers  would choose for long term reliabily, a NTC or digital sensor like the DS18B20 ?

I'd choose the NTC because digital communication and chips are prone to noise. I have had SPI temperature sensors fail due to too much noise on the board. The SPI communication ran fine it was just the chip itself which crapped out.

[jdraughn]

cool chip, thanks jdraughn!

Here are the breakout board files I made in Eagle for the MAX31725 if anyone wants them. it's 80 cents for 3 boards from OSHPark.com.