Selecting Temperature sensor IC

[sam_kevin]

Hi, Could some one help me out in selecting a temperature sensor IC for my project.

I need to sense the temperature of the refrigerator which will drop to minus 30 deg Celsius, say the sensing range should be -30 to +40 deg Celsius.

The device that I am using has only one ADC pin, and the distance between my sensor and the device will be about 10meters long, Kindly suggest me sensor IC or guide me how to overcome the wire resistance as the wire length is 10Meters. the accuracy can be +- 2%.

I am new to electronics I am wishing to do this project by my own, Kindly guide me with better solutions. Thank you

Yours faithfully
Sam.

 

[CocaCola]

DS18B20

If you need to adjust for wire resistance simply do that in the firmware of the device reading the temp sensor...

As for accuracy you said 2%, 2% of what the entire range, or per degree? If +/- 0.5 degree isn't going to work neither is the chip I suggested...

As for others lots to be found in a simple Google search...

 

[sam_kevin]

D18B20 Ic is one wire Digital thermometer, I cant use this IC with my device, as my device has only one ADC pin, It is the GSM device with inbuilt UC where i can't program.

How about using AD22100 IC ?
,

 

[duke37]

The venerable AD590 gives a current out proportional to temperature so cable resistance (two wires) does not affect the reading. A resistor at the receiving end would convert this current to voltage for an ADC.

How does a one wire device work?

 

[CocaCola]

D18B20 Ic is one wire Digital thermometer, I cant use this IC with my device, as my device has only one ADC pin, It is the GSM device with inbuilt UC where i can't program.

You can you would just need to build a micro front end that does the DAC, and outputs to your device... This also allows you to adjust the output to the exact range your device expects to see for whatever temp swing, and even make any output changes to correct error due to the length of the wire if that is a problem...

At this point we really know nothing about what your device expects to see and what range it expects to see...

Example is +5V equal to +40 and 0V equal to -30? I suspect not, and this is why using a micro to adjust the single to your devices expected input range is beneficial unless your device is designed to work with a specific over the counter unit that you can simply purchase...