Interfacing a 12-bit temperatur sensor with ATMEL controller

Hi all,

I plan to build an air conditioning device for the entire house with each room controlling the temperature individually.

Since temperature differences of 0.5 degrees are already considered as a big difference by people I want to make control with an accuracy of 0.1 degrees. ATMEL controllers have A/D converters, but they just have a resolution of 10 bits which would result in an accuracy of 0.5 degrees.

Has anyone tried to interface a precision temperature sensor 12 bit or more to the ATMEL?

If so, I'd appreciate some hints how to manage that.

The MCU just has to manage one analog input and will return two logical outputs, one for cooling and the other one for heating (if necessary) and of course, an LC-display, one UP, one DOWN and one ENTER key.

Regards

Hans

Challenge your assumption that 0.1 degrees accuracy implies that you need 12-bits for 0.1C resolution/accuracy (not the same, actually). It appears to be based on a range of (4096 * 0.1) = 409 degrees. Consider adjusting the A/D input so it sees 0V at 15C, and 2V (511-512 bits) at 25C, and 4V (1023 bits) at 35C. You'll have (10/512) or about 0.02C resolution.

Your accuracy is determined by the sensor and the circuit that you use to scale the input, less so by the ADC.

Well...

Well,

Please see this thread: Yes i've got answer...

Regards,

Simran..